Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Martin6 on March 15, 2023, 09:28:37 AM
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Hi,
As mentioned in a previous topic, Im looking into why my new 750K6 is reluctant to tickover and run, particularly no.4, along with a stiff throttle that won't return on its owm. The ignition / timing looks ok. Plugs will be replaced.
I've removed and cleaned the carbs and fuel lines. I found 2 things;
-Floats were set at around 30mm above the bowl rim. So maybe it was lean? I've put it to 26mm and will watch out for leaks!
- I was unable to see through two of the slow jets (one was no.4). Hopefully, now all clean.
I'm not familiar with Keihin, nor multi carbs set ups. Im used to single Amals! At this stage, I only cleaned what I could get to from the float bowl without dismantling them from the gantry system. I'll replace the fuel, the tank is very clean.
I'll crack on this morning. A couple of questions:
I know the carbs were not synch'd prior to taking them off. Is there a good method to getting a base setting on all 4, before re-installing? I have vacuum guages for once it's running (that will no doubt, be fun and games!).
The issue with the throttle not springing back remains a mystery. Cable run is smooth arcs. They were a little, very slightly, stiff. I don’t think this was the issue. I've flushed them through with silicon lube. They are now nice and light. Off the bike, the throttle movement on the carbs gantry is very stiff. Im not able to shift it manually. On the bike, once the cables were removed, they did operate and spring back. The springs look ok. Should I be lubricating something, or easing any clearances? Is there perhaps a 'usual cause' for this?
Thanks, Martin
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Hi Martin, I’ll give it my best shot until someone that has more knowledge comes along. With the idle adjust screw backed off to ensure fully closed sliders, viewed from the intake side of carbs use a plastic WD oil delivery tube or similar ad Nurse Julie suggests and set each slider in turn to get uniformity accross the four. This is the tried and tested bench sync method which can be tweaked with bike running and a vacuum sync.
The carb throttle stiffness, have you disconnected throttle return spring to see where the problem lies? Make sure all clean and no binding with the air intake sliders.
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A very basic thought is the twist grip nice and free, the one on my 500 was quite stiff when I removed the twist grip the tube was split causing binding.
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Accurate bench synchronisation of the carbs is easily as good as later "gauge" methods, they don't hold superiority over diligent setting in the first place. Once you have set them off the bike, made sure that you can close the slides fully by turning down the master tickover screw (the big one that controls idle rpm ) confirmation that you can modulate right down to zero on the carb bank, then that's good enough to run.
It holds advantage in diagnosis too, in that if there's fault of ignition or jets impaired/worn then it allows you to see that error rather than chase your tail by adding inappropriate adjustment to carb balance.
Worth stating the purpose of any multi carb balancing, that is to ensure the slides and hence air volumes are the same under full load, it's not a method for trimming idle smoothness, just coincidental that the idle should be smoother when the slides are set at parity.
Individual cylinder denand AT IDLE is emphatically set by adjustment of the low speed mixture circuit AFTER the slides have been correctly set. There's clear information and routine in Honda's manual that describes this schedule.
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Thank you. All very encouraging :)
The WD40 spray tube suggestion, im thinking all adjustment just done with what the manual calls the 'adjuster screw' above the top of each carb?
I checked the handlebar throttle tube, the action seems fine. That's all back together awaiting carbs to connect up the cables. Before connecting the cables, pushing on the 2 large U shape castings on the gantry, it seems to open and spring closed OK. Maybe just needed the cables lubing. I'll try it, before I get new cables.
Edit: With the master tickover screw fully out, all slides are fully down, as I raise the tickover screw, the slides all seem to start moving in unison. A WD40 straw is a fraction too large to fit into the cutaway on the intake side. I'll adjust the tickover screw to allow that and start the bike from there. Just have to get them back on now!
Cheers, Martin
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Silicone oil or grease only for the cables, else you'll get problems.
There needs to be enough slack in pull cable such that it doesn't go tight when turning the steering from full lock to opposite. Seems loose in absolute terms, but needed to avoid a conflict between the two cables that will also make throttle action difficult.
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Yes, silicone used. I will adjust the lower cable for initial slack. Thanks.
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Strange. As soon as I connect the throttle opening cable, the carbs don't close. Also, the return / close cable seems far too short. As soon as it is connected even at its loosest, it is not allowing the throttles to fully close, even manually. There's not enough cable length.
Ive rechecked routing and the bar mechanism. I'll have another look tomorrow, I may be adjusting it all wrong. I've ordered new cables anway.
So, that was the dull bit. I was naughty and removed the return cable and went for a short ride. Fantastic. Handles better than I expected, sounds great. The bike is starting, ticking over, running on all 4. Idle below 1500rpm is lumpy but smooth above that and I sense it wants to pull more at 4-5,000rpm. Pretty sure a carb tune would sort it. However, the rear brake pulses badly. So that's next on the list ::)
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Is your K6 a UK model with lower handlebars or a USA model with the high bars? Have you got a photo of the bike?
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It's a UK bike. Registered June 1977. K6 engine and frame numbers. Lower UK bars. The standard cables should work.
At the bar end, the throttle tube looks old, but undamaged. It rolls smoothly.
I think the gantry is ok. At the gantry end the max slide lift is about right (just under 33mm) and the 'overcross stop adjustment' is in spec at about 3mm. The springs are strong and look fine.
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OK. If you need any photos, cable routing etc, just shout as we have a UK K6 here.
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That's very kind, thank you.
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I might have found the issue for the cables. Reading the manual, there was a throttle grip adjuster on the underside of the righthand switchgear. This was discontinued from K4s. Mine has the screw adjuster, so it may be an earlier switch set. Does that mean the cables will need to be different?
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I might have found the issue for the cables. Reading the manual, there was a throttle grip adjuster on the underside of the righthand switchgear. This was discontinued from K4s. Mine has the screw adjuster, so it may be an earlier switch set. Does that mean the cables will need to be different?
No, the cables will be the same. Make sure the screw isn't wound in to tight thus causing impingement
Just a thought, has someone glued the throttle tube on, as this can cause stiffness as the glue will be pushed down to the end. Don't ask how in know this 🙄🙄🙄🙄
Edit, forgot to ask if you have the cable routing correct for a UK model as its different to a USA model.
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I've taken a photo, this is our UK K2 but the routing is the same for the UK K6.
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So, that was the dull bit. I was naughty and removed the return cable and went for a short ride. Fantastic. Handles better than I expected, sounds great. The bike is starting, ticking over, running on all 4. Idle below 1500rpm is lumpy but smooth above that and I sense it wants to pull more at 4-5,000rpm. Pretty sure a carb tune would sort it. However, the rear brake pulses badly. So that's next on the list ::)
Assuming the carbs are balanced, the low speed setup is essentially the same as your "single Amal" in that the routine for idle mixture adjustment is to wind the screw to give highest rpm, then a bit more to see that cylinder start to falter as it gets too lean, finally back it down (richer) to give 100 rpm drop and that's the set point. You've just got to do that 4 times, one after another to set the low speed mixture as manual describes, they can be different one to another rather than set them all to X turns out . Its all fairly simple in reality.
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I've taken a photo, this is our UK K2 but the routing is the same for the UK K6.
Thanks for the photo. That's interesting. The route is the same, but my current throttle opening cable is much longer and curves out further. I have replacements on order.
Looking at the DS parts, the part no.s are different for the closing cables between K3 and K6, so I assumed they are different? Be great if they're the same. I ordered the K6 versions, so I'll give them a try. If they are wrong, I wonder if I can cut a section of the outer sleeve, to increase the bare cable length, "cut'n shut"!
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Assuming the carbs are balanced, the low speed setup is essentially the same as your "single Amal" in that the routine for idle mixture adjustment is to wind the screw to give highest rpm, then a bit more to see that cylinder start to falter as it gets too lean, finally back it down (richer) to give 100 rpm drop and that's the set point. You've just got to do that 4 times, one after another to set the low speed mixture as manual describes, they can be different one to another rather than set them all to X turns out . Its all fairly simple in reality.
I've only balanced them off the bike. The gent I bought the bike from has given me the 4x vacuum guage kit for 'Dynamic balance'. I have an itch to use it, but it could be a maze I get lost down!
All 4 are set at 1 turn out of the pilot screw, so that will need checking when I get it warmed up next. Hopefully it is fairly obvious when one of 3 cylinders starts to falter. I don't follow the 100rpm drop bit in bold? On the Amals it's also an air screw. Bike fully warmed through and I wind in until it falters then back out until stable (revs rise) and leave it there. = the point of richest smooth running.
Thanks for your help. Appreciated.
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New throttle cables have arrived and I've installed them. What I've found is the right hand side handlebar switchgear is not seating cleanly. I think the two wires that connect to the starter button are being squashed against between the handlebar and the swirch casting. As a consequence, the two halves of the switchgear casting don't come together evenly. There could be extra pressure on the throttle slider, which may be enough to resist the throttle returning by itself, possibly. Plus, the wires are getting damaged from being pinched.
That said, I can't see how they could be routed differently. The manuals are silent!
Does anyone have (for a K6) a photo or diagram of how the wires are soldered onto the starter button?
Struggling to explain this. The starter button pushes a pin (which is inside a tiny spring). There's a white plastic part with a brass insert, that the pin pushes onto. A wire is soldered to the top of that brass piece. That is the wire that seems to be trapped when I try to screw the two halves of the switchgear housings together. On mine, the soldering looks old, but not factory. So im wondering if an old fix has introduced a problem? Should the wire be soldered to the top of the brass piece? If it is, I can't see how it can leave enough room to cleanly clamp the two halves of the casting together.
Thanks, Martin
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Martin, I think you've already said as your K6 is a UK model, your handlebars are the UK style, being lower than the USA model ones. Do you have UK K2 switch gear fitted and are the cables you've bought the short type needed for UK models and not the longer cables needed for USA models. USA model K3-K6 parts are different than UK model K2 parts and the parts aren't interchangeable.
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Julie,
Bike is UK. My bars are UK. I fitted the new cables yesterday. They are also UK and seem fine.
You are right, I'm not sure about my switchgear. I may be confused... If a UK K6 has the sprung screw under the bottom half of the switchgear (which screws up into the throttle tube housing), then it might be right. I had read that this was discontinued on K6s?
My [current ::) ] problem seems to be the wires for the starter button not having enough space to get from the switch to inside the bars. The red/yellow is the main problem, although the black is also tight. I suppose, possibly wrong switch for the bar holes, but I'm suspecting it will work, if the soldered connection is right.
I'd like to somehow check that the red/yellow is soldered correctly on to my switch.
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We have our UK K6 on the ramp for it's yearly service. The UK K6 has the sprung screw fitted to the switch.
I have taken some pictures of the switch and a switch that has been taken apart so, you can see how the Yellow/Red and the black are connected .
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Good job Julie. Looks like could do with a bit of a clean.😜
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Darned sight cleaner than mine!
Thank you very much Julie. I think that's my switch and I think the joints are currently different. Will double check this morning and crack on.
Thank you for your help. Really brilliant. :)
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Interesting. My red/yellow is where your black is and vice versa. Doesn't matter, but shows mine has probably been repaired before. Except, where your black goes in from the underside, mine (R/Y) is soldered to the top. This is causing my problem. Just not enough space to route between the bars and the switch. So, if there's enough wire, I will change that. Fingers 🤞.
Thanks again.
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Assuming the carbs are balanced, the low speed setup is essentially the same as your "single Amal" in that the routine for idle mixture adjustment is to wind the screw to give highest rpm, then a bit more to see that cylinder start to falter as it gets too lean, finally back it down (richer) to give 100 rpm drop and that's the set point. You've just got to do that 4 times, one after another to set the low speed mixture as manual describes, they can be different one to another rather than set them all to X turns out . Its all fairly simple in reality.
I've only balanced them off the bike. The gent I bought the bike from has given me the 4x vacuum guage kit for 'Dynamic balance'. I have an itch to use it, but it could be a maze I get lost down!
All 4 are set at 1 turn out of the pilot screw, so that will need checking when I get it warmed up next. Hopefully it is fairly obvious when one of 3 cylinders starts to falter. I don't follow the 100rpm drop bit in bold? On the Amals it's also an air screw. Bike fully warmed through and I wind in until it falters then back out until stable (revs rise) and leave it there. = the point of richest smooth running.
Thanks for your help. Appreciated.
To clarify as its doing the same thing, but possibly different interpretation.
Starting with the adjustment screws as you've set them (1 turn out) turn further out and revs should rise as it will get leaner on these carb. Keep turning very slowly and small increment, then that cylinder should go too lean and you'll just hear it start to falter/miss a little (this confirms you're at balance point of decent mixture) now turn the screw back inwards slowly until the revs just start to drop (honda say this should be 100 rpm drop) which makes it's just a little richer to finally set the position there.
Each carb can have a different final set to give even cylinder burn, this is the low speed synchronisation method for these carbs.
If you now put the vac gauges on them, they should show as in tolerance noted in the manual, not needing any more adjustment.
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Thanks everyone. Switchgear's all back together and a nice snap on the throttle. Now for a quick run, so i can tweek the carbs. :)
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Happy with the run :D. Not happy with the corroded spring on the starter button. A Google search took me to Julie's ebay store. Replacement on order. :)
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My starter button was very loose and wobbly and the starter actually came on when I pulled out from getting fuel. It was ok if I pulled it back out, not a long term solution. On inspection, the spring around the button's brass plunger was in several pieces inside the switch and doing very little. A new button and spring arrived today (thanks Julie).
I've spent about 6 hours trying to get the starter switch back together. It looks like the one in Julie's picture and the button is identical to the original, so the new parts are right. I cannot get the two contacts into the switch whilst the button and spring are in there. I've managed to break the solder joints a couple of times trying to get it assembled. How I laughed...!
Is there a knack to this?
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Are you trying to do it with the switch gear still on the bike? The knack is to take the switch gear off the bike and do it at the kitchen table with a cup of tea 😁😁😁😁
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Yes, switch still on the bike. I really don't fancy taking the wiring out of the 'bars. Seems to make it a bigger job, as I'd have to remove the wiring from the top of the switchgear too and get into the headlight bowl?
I actually dreamt about this last night ;D
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So it's not just me who goes to bed and dreams of how much is involved in fixing something! 🤔🤔🤔
I am an overthinker so sometimes see a load of problems rather than the outcome / solutions.
Once you get into the headlamp bowl take plenty of photos & make notes on wiring colours and if a connector is male or female. Once you have identified the switch cable wires and disconnected them you can pull that small bunch out of the headlamp & refit the bowl to keep it in place.
Pulling out the wires from the bars is pretty easy you can attach a piece of string at the end so when the wiring is out you have a length of string in place. You can carry out the repair as Julie has said so much easier in the house or on a garage bench.
When fitting back might be easier to loosen the bars so you can rotate them to see your wires as they start to exit the bars - I used some surgical forceps to tease the ends out.
An alternative is to use a length of old nett curtain rail spring as a lead - it works a treat.
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Yep, I'm going to have to pull it off. I've packed it back up a few times and turn the ignition and the starter kicks straight in. Maybe the plastic retainer might not be holding the copper earth firmly enough, so the spring pushes it onto the positive plate..it does look ropey. Or maybe a short in the wiring, after all my attempts.
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We have our UK K6 on the ramp for it's yearly service. The UK K6 has the sprung screw fitted to the switch.
I have taken some pictures of the switch and a switch that has been taken apart so, you can see how the Yellow/Red and the black are connected .
Julie,
Can i ask a question on your photos?
Your 3rd photo shows a metal plate angled away from the starter switch, underneathe it? Screwed into the bottom of the switchgear case. I don't have that, but I do have a metal pin in the hole next to it in your photo, which locates into the handlebar, to stop the switchgear rotating. Do i need that angled metal plate? Or is it just a different version?
Many thanks,
Martin.
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We have our UK K6 on the ramp for it's yearly service. The UK K6 has the sprung screw fitted to the switch.
I have taken some pictures of the switch and a switch that has been taken apart so, you can see how the Yellow/Red and the black are connected .
Julie,
Can i ask a question on your photos?
Your 3rd photo shows a metal plate angled away from the starter switch, underneathe it? Screwed into the bottom of the switchgear case. I don't have that, but I do have a metal pin in the hole next to it in your photo, which locates into the handlebar, to stop the switchgear rotating. Do i need that angled metal plate? Or is it just a different version?
Many thanks,
Martin.
Hi Martin. I have absolutely no idea what that bit is, or what it does, I just found that switchgear to show you the start button on a twin wire system. My thought on it though is that it's an earth tab as the switchgear obviously needs to be earthed. If your switch gear has the pin to locate into the handlebars, that would be the earth point.
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I believe it's the ramp to tension against the throttle screw on the throttle control - you can see the silver screw in the picture (second picture) - it gives you idle speed adjustment on the handlebars ?
They fall out of position easily when you undo the clamp.
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We have our UK K6 on the ramp for it's yearly service. The UK K6 has the sprung screw fitted to the switch.
I have taken some pictures of the switch and a switch that has been taken apart so, you can see how the Yellow/Red and the black are connected .
Julie,
Can i ask a question on your photos?
Your 3rd photo shows a metal plate angled away from the starter switch, underneathe it? Screwed into the bottom of the switchgear case. I don't have that, but I do have a metal pin in the hole next to it in your photo, which locates into the handlebar, to stop the switchgear rotating. Do i need that angled metal plate? Or is it just a different version?
Many thanks,
Martin.
That's a cable clamp Martin, the wires pass beneath it and would account for why yours are fouling the bars and getting trapped.
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My switches are apart right now if you want a pic of how the starter button looks dismantled.
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My switches are apart right now if you want a pic of how the starter button looks dismantled.
Further pictures would always help.
- I think it will be crucial to get the angle right on the wiring, so it routes into the bars without getting trapped.
- Also be good to see the assembled white plastic piece a bit clearer. I can’t currently see how that is sufficient to stop the copper tab it holds from being pushed into the positive connection in the switch.
Thank you.
I have the wiring out, headlamp loom all labelled up and string through the bars. I can see the insulation on the two switch wires has opened up where the wires were entering the bars, so possibly they were shorting. I also have a concern that the plastic piece that holds the copper negative (earth) tab steady against the spring on the button spindle, may be too worn to stop the spring from pushing the earth tab onto the positive contact patch. Will have to think of a way to hold it, if that's the case. Will hopefully be easier to check in the kitchen.
I will try to pull some length of R/Y and Bk through the sheath to get to sound wire for the starter switch. But may have to cut it open. Shame, because the sheath looks ok.
Thanks for your comments and help.
Martin
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I am not sure why you refer to a earth wire ? As the pictures that i have already posted have no earth wire ::)
Earth is the switch to handle bars. Black is live to the button and Yellow / Red is to the solenoid. The button is the connection between Black and Yellow sending a live signal to the solenoid .
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Yep, my mistake. Thanks. I do mean the copper tab with the black wire attached. Guess I'm no auto electrician! :-[
I'm wondering if the connection is wrongly being made by the 'live' tab, because that tab is only held back against the pressure of the button's spring by the white moulding it sits in. My white moulding looks a bit mouldy! :)
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It's really daft, to my embarrassment, I'm still struggling with this darned starter button. I have it off the bike, wired and assembled as per Julie's photos.
As soon as I place the live tab into the switch, even though the button spindle goes through the little hole in the tab nicely, the tab is pushed by the button's spring against the R/Y contact. So, the circuit is always complete. I've tested it on my meter and as soon as the button is pressed once, that's it, the tab remains pushed against the contact.
I think the plastic piece that holds the tab is what is intended to hold the tab away from the contact. It must be worn.
Options:
- get a new one. No longer available.
- Try to modify it?
1. I could put insulating tape on the face that is touching the R/Y contact, with hole in it, so the button pin can still go through and complete the circuit on the contact. Perhaps not a long term solution?
2. Glue a spacer on the bottom of the tab, to keep it away from the contact? Would have to be very thin and it might not be possible to get it into the switch, as it's already very tight.
Any suggestions? :)
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Hi Martin! You are certainly being tested to the limit there!😡😡. Having done a couple of these fitted new spring and button as well as general cleaning and refurbishment. I’m finding it difficult to visualise what is going on there. I’m quite sure if it’s fitted correctly and the spring is pushing the button out again it should disconnect the circuit. Double check against photos sent with switch gear internals to ensure proper assembly. It can be a little fiddly to put together, but I’m sure you don’t need any glue unless there’s something broken. Sorry! If this isn’t that helpful, but good luck anyway.
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If all else fails https://www.ebay.co.uk/itm/185407260951
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If all else fails https://www.ebay.co.uk/itm/185407260951
Bit of a cop out Ted! Good shout all the same.😂😂
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Hi Martin! You are certainly being tested to the limit there!😡😡. Having done a couple of these fitted new spring and button as well as general cleaning and refurbishment. I’m finding it difficult to visualise what is going on there. I’m quite sure if it’s fitted correctly and the spring is pushing the button out again it should disconnect the circuit. Double check against photos sent with switch gear internals to ensure proper assembly. It can be a little fiddly to put together, but I’m sure you don’t need any glue unless there’s something broken. Sorry! If this isn’t that helpful, but good luck anyway.
Hi, thanks for your reply. Yes, the spring is pushing the button back out.
It is difficult to explain in writing: the spindle in the button goes through a hole in the 'live' tab. The spring around that spindle pushes against the live tab. By 'live tab' I mean the right angled piece of copper that has the black wire soldered to the top and a hole for the button pin to pass through. The action of the spring against the live tab is enough to force that tab against the RY contact, so it is closing the circuit, whether the button is pushed or not. I think the white nylon / plastic piece that screws the live tab to the switchgear housing, should hold the live tab firmly, so it doesn't move. Not the case on mine.
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If all else fails https://www.ebay.co.uk/itm/185407260951
Thanks. Unfortunately, the K6 also has the lights switch on this RHS (the P/H slider).
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If all else fails https://www.ebay.co.uk/itm/185407260951
Thanks. Unfortunately, the K6 also has the lights switch on this RHS (the P/H slider).
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So its this one just in case.https://www.ebay.co.uk/itm/184159105630?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D247414%26meid%3D11c778b6b451483cad2b1e56e37d375a%26pid%3D101195%26rk%3D3%26rkt%3D12%26sd%3D294090172332%26itm%3D184159105630%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV4V5V6ItemNrtInQueryAndCassiniVisualRankerAndBertRecall&_trksid=p2047675.c101195.m1851&amdata=cksum%3A18415910563011c778b6b451483cad2b1e56e37d375a%7Cenc%3AAQAHAAABYBEC%252B8HimpTF6XPanG8lCeF3G6jifrewDlLoKJMPz0RnJH8s%252BUBlIo2cSQSdgSGvSW%252BiypWzATNrgsi2agxJDshTUcICtN84koFIxBjyT3J0Yv2cJO9SxJpCd6oLiUW1WFpLF3ZtVHQyxywf3rDdRkKNWEEBcurfD3jE2Tlfu7RbjZKX%252BgX%252FevqzJ97KPLwVqmhsRrMSTOvtjBZbvNmisHdOTXmxNv%252BCAJ4JJTFyR0P%252B%252FSqOMdsJooTa5p%252FV%252Bf2YEv0oNUwYpxQhRFZTjU3aVWEDOHt%252B0BXNtvHBzkyIdmCvDH6NBIR3Z1sQduvdSIUyVK1XJhUb91bLPVXu5%252BbyUMia4eBxQPfflZ8XORAxWVkMj%252FD5Uo5KRw4QMJFrP4X2NX70M%252B79Ze%252B4ia1N3L1RGKmCEVP64vz2z%252B8fl7zUJerxUoPmD7irtknkzDKgHZdUsIgEjJzvSwjMocyX8SCLjn8%253D%7Campid%3APL_CLK%7Cclp%3A2047675
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If all else fails https://www.ebay.co.uk/itm/185407260951
Thanks. Unfortunately, the K6 also has the lights switch on this RHS (the P/H slider).
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So its this one just in case.https://www.ebay.co.uk/itm/184159105630?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D247414%26meid%3D11c778b6b451483cad2b1e56e37d375a%26pid%3D101195%26rk%3D3%26rkt%3D12%26sd%3D294090172332%26itm%3D184159105630%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV4V5V6ItemNrtInQueryAndCassiniVisualRankerAndBertRecall&_trksid=p2047675.c101195.m1851&amdata=cksum%3A18415910563011c778b6b451483cad2b1e56e37d375a%7Cenc%3AAQAHAAABYBEC%252B8HimpTF6XPanG8lCeF3G6jifrewDlLoKJMPz0RnJH8s%252BUBlIo2cSQSdgSGvSW%252BiypWzATNrgsi2agxJDshTUcICtN84koFIxBjyT3J0Yv2cJO9SxJpCd6oLiUW1WFpLF3ZtVHQyxywf3rDdRkKNWEEBcurfD3jE2Tlfu7RbjZKX%252BgX%252FevqzJ97KPLwVqmhsRrMSTOvtjBZbvNmisHdOTXmxNv%252BCAJ4JJTFyR0P%252B%252FSqOMdsJooTa5p%252FV%252Bf2YEv0oNUwYpxQhRFZTjU3aVWEDOHt%252B0BXNtvHBzkyIdmCvDH6NBIR3Z1sQduvdSIUyVK1XJhUb91bLPVXu5%252BbyUMia4eBxQPfflZ8XORAxWVkMj%252FD5Uo5KRw4QMJFrP4X2NX70M%252B79Ze%252B4ia1N3L1RGKmCEVP64vz2z%252B8fl7zUJerxUoPmD7irtknkzDKgHZdUsIgEjJzvSwjMocyX8SCLjn8%253D%7Campid%3APL_CLK%7Cclp%3A2047675
I owe you a pint! Switch ordered.
I hate to concede defeat, but 2 1/2 days on that bl***y switch is enough. Long lead time for delivery, but I have a back wheel to build anyway.
Thank you again Ted and thank you to everyone who has pitched in.
Martin
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That's a copy switch Martin, in case you didn't know.
How can you tell? Very easily. The original switch doesn't have the dot coloured in red next to the P and H, the copy does. I don't think the quality matches the original Honda switches but it does the job and looks the part. If you want the throttle control system just drill the small lug on the bottom between the cable outlets 4mm, tap out to 5mm and fit the sleeper ramp inside the switch and the thumb screw and spring on the outside, I have them all NOS if you're interested. Comes in very handy on the motorway, just wind it in till the throttle sticks and you can avoid all that wrist stress of keeping it open, you can still operate the throttle if needed, it's just a bit heavy until you wind it back out again.
I've just done my switch halves again last night at 3am, filling in all those little letters etc. I often wondered why Honda left some unpainted but filled in the others, I did them all on my 2 R/H switches, even went further and did the run and it's corresponding dot in green as I think that's appropriate, green for go and red for stop seems to make sense to me. Just need to clean up the overpainting and they are ready to reassemble.
(https://i.postimg.cc/Dyw8zB9z/IMG-3104.jpg) (https://postimg.cc/8sx1KBP8)
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Just had a thought Martin, if the R/H switch you have is going spare I'd be interested. I'm trying to get a collection of broken switches and see if I can get some complete ones out of them, a little work and they'll be better than new and back into the community again.
Do something like this. Have them ceramic coated, repaint the letters, restore the interior parts and contacts, repair any wires that need doing, re-sheath the wires and then offer them to owners of our bikes.
(https://i.postimg.cc/T1CgLzZh/IMG-3106.jpg) (https://postimg.cc/644yFm6N)
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Looks good.
The red dot by the P is there on my current ones. They are very faded, like the anodising had been sunbleached. I assumed they were original. Maybe in the past someone has painted in the dot. :)
Bit disappointing if they are copies, the ebay ad stated NOS. Hopefully, they'll work fine. 🤞
As folk may have gathered, my bike is not concours! At this stage I just want to get it back on the road and some miles on it.
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Nice work on the switches there Ken! They are looking good!
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Just had a thought Martin, if the R/H switch you have is going spare I'd be interested. I'm trying to get a collection of broken switches and see if I can get some complete ones out of them, a little work and they'll be better than new and back into the community again.
Do something like this. Have them ceramic coated, repaint the letters, restore the interior parts and contacts, repair any wires that need doing, re-sheath the wires and then offer them to owners of our bikes.
Odd job, I'd be happy to do that. First I'd just like to check the ones that are coming, to make sure they work / I'm happy with them. Do you also do this with other parts for these bikes?
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I do it with almost everything I can. I like to see if I can reclaim stuff that would end up in the landfill otherwise.
The switch is 100% a copy, the wires are wrong for a start, Honda didn't use that colour bullet connector, plus they have over a hundred of them, no way there is still over 100 original switches out there, I doubt there is 100 NOS originals in the entire world never mind one supplier. That's one of the drawbacks in buying copies, they can get connectors wrong, wire colours wrong etc.
For instance, on the original switch wiring, which I have in front of me, there is a male brown/blue wire, can't see that on the pic, male yellow/red which is there, male black/red which is there, there are 3 male blacks and there looks to be 4 on the pic, there is also a female black/white and that's missing as well. That's for the kill switch BTW.
Lots of switches these days have been repainted so it's no surprise to find your red dot is there, look at the CMS pic of an original switch, check the wiring, note the missing red dot. https://www.cmsnl.com/honda-cb550f2-super-sport-550-four-1977-england_model17121/swassy-statkill_35150377013/ Check out that price!!!!!!!!!!!!!! Now the copy switch from the same supplier, he has 2 versions, this one gets the wires right but has the red dot, https://www.cmsnl.com/honda-cb550f2-super-sport-550-four-1977-england_model17121/swassy-statkill-non-oe_35150377023p/ this one also has the red dot but note he doesn't show the wiring, they look ok BUT he's hiding them behind the switch so you don't know if the female black/white is there, https://www.cmsnl.com/honda-cb550f2-super-sport-550-four-1977-england_model17121/swassy-statkill_35150377013p/
Coming on Johnny, busy fixing the switches together as we speak.
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Sorry Martin, just realised yours is a 750K6 and I've been posting links to the 550F2 switch, same switch, just longer wires.
K6 switch, https://www.cmsnl.com/honda-cb750k6-four-england_model14383/switch-starter_35150341600/ looks to be the same 7 wires. Except they are shorter as yours go into the headlight and the 550F2 go under the tank so need to be longer. Oddly is does have the red dot. https://www.ebay.co.uk/itm/295536686286?hash=item44cf5bf4ce:g:O9sAAOSwtCNePTcK&amdata=enc%3AAQAHAAAA4NJHm%2FISXriuA0Bw47xIdnukoYeTLBAFf8r807pD3RIwDTIIybRsIF0XWx6KjFwJ96HEW2GeM9e6RmUpuotpwc2gslndU0KrVVwePRkT928E0owFLJOD8L5cobh94WVJjHPaJMEeSE%2FEntZJWKxgOqZPQOk0Iyi569PKNtZCABQMWHU6yI8NedtauaDUBg6j%2Bngl3owaqn0QQkx9E6sAq1lrGpdmyl%2BpeDh0bCzUNupPfVT13YfP5L214AOQezK0ZcdqqwhLUY71hSODb2fruIJFDQNuCoNn3mo2BT2q6tRC%7Ctkp%3ABk9SR76KvM7iYQ
Check out that price!!!!!
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Thanks. Yes, a K6. I could always paint a black dot :D
I'll be interested to see what connectors and wire colours arrive. Guess, if not clear, I may have to open up the kill/light switches to continuity check and label them up. I can x-ref against my current switch to help.
Hopefully, there's enough room inside the headlamp bowl to fit any extra length of wire!
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I've just reassembled all 3 of my switches and 2 of them were R/H ones. I must say they were fairly easy to do and the starter button was pretty easy, it's just getting it fitted in the right order.
Just in case you feel like having another try I'll describe how it's done. First fit the horn button, after greasing the spring up really well so it doesn't rust in the future, the horn button has a flat side on the flange, this goes uppermost inside the switch, if you can read the TEC writing on the button from the outside it's in the right way. Next fit the yellow/red connector plate, this is shaped so there is a curve at the bottom, it slides into a recess in the switch housing, the next bit was slightly tricky but not even remotely hard, slide the white housing down into place whilst holding the horn button back with a small flat bladed screwdriver, you may have to pull the spring back a little, push it into place and secure with screw whilst holding the white box hard up against the wall of the housing, it has 2 flanges which push against the front wall. There should also be a shaped plate which screws into the housing which holds all the wires from the upper part of the switch in place inside the bottom part of the switch. I'll post a pic later today showing how it should look. That's it mate. Easy peasy. All I need to do on mine now is test all continuity when the switches operate and make sure they are no shorts, easy to do when you've unsoldered the kill switch plate, it's very close to the body when assembled.
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Odd job,
Yes, I understand that, the issue I have is that the white plate you mention was separate from the copper live tab (what the black wire is soldered on to). So even when fully assembled, white housing screwed down, the pin of the button nicely through and sliding into contact with the yellow/Red plate, the copper live tab was just pushed against the Y/R plate by the button spring and starter remained on.
I must have assembled it half a dozen times on the bike, but when I took it off, I could see no way to stop the live plate from moving under the springs pressure into the Y/R plate. I assume that live plate should be firmly fixed in the white holder, so they were a single unit holding it firmly against the spring pressure. Mine had separated, broken. So that 50p part caused my problem!
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There have been two beneficial side effects of my nearly 3 days on the starter button:
1. Getting the headlamp off to release the switchgear wiring was the prompt to investigate the pilot light, which wasn't working. No bulb inside the mounting was the cause! New bulb fitted, should be good to go.
2. As I rotated the bars to ease the wiring through, brake fluid started oozing out of the m/c banjo. Why did I feel the urge to pull the brake lever to see if it was brake fluid! A 20 minute general wipe down and clean up followed. Luckily, it was only loose and I could feel the bolt crushing the washers home as I tightened it. So far fine after bleeding some air out. I'll keep an eye on it.
I did know some of the fixings were loose, one of the front mudguard stay bolts came adrift when I trailered the bike home, prompting some general checking (lower rear shock bolts were also loose). But I'd missed the brake line fittings. I'll check top to bottom again.
The joy of old machinery ;D
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Odd job,
Yes, I understand that, the issue I have is that the white plate you mention was separate from the copper live tab (what the black wire is soldered on to). So even when fully assembled, white housing screwed down, the pin of the button nicely through and sliding into contact with the yellow/Red plate, the copper live tab was just pushed against the Y/R plate by the button spring and starter remained on.
I must have assembled it half a dozen times on the bike, but when I took it off, I could see no way to stop the live plate from moving under the springs pressure into the Y/R plate. I assume that live plate should be firmly fixed in the white holder, so they were a single unit holding it firmly against the spring pressure. Mine had separated, broken. So that 50p part caused my problem!
Sounds like someone tried to re solder the wire on and it got too hot, which melted the plastic.
The switch you have is very rare and hard to find, only fitted to UK / european K6's. Trigger has loads of switch gear parts here. If you send me your old rare switch, i can fit some parts and it will be as good as new FOC.
It would be a shame to lose a original part for the sake of one small part and 10 minutes work.
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Hey, good on you Julie👍
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Sounds like someone tried to re solder the wire on and it got too hot, which melted the plastic.
The switch you have is very rare and hard to find, only fitted to UK / european K6's. Trigger has loads of switch gear parts here. If you send me your old rare switch, i can fit some parts and it will be as good as new FOC.
It would be a shame to lose a original part for the sake of one small part and 10 minutes work.
What an amazing offer. Very kind. I have a replacement on order, which I don't mind using. But, if it is not correct, I will take up your kind offer. 👍 I'll find out in a week or so.
It may well have been my fault, that bottom wire retaining plate was missing and the wire was hanging on by a couple of strands and I did try a repair in situ. That probably damaged it. Lesson learned (again!).
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Sounds like someone tried to re solder the wire on and it got too hot, which melted the plastic.
The switch you have is very rare and hard to find, only fitted to UK / european K6's. Trigger has loads of switch gear parts here. If you send me your old rare switch, i can fit some parts and it will be as good as new FOC.
It would be a shame to lose a original part for the sake of one small part and 10 minutes work.
What an amazing offer. Very kind. I have a replacement on order, which I don't mind using. But, if it is not correct, I will take up your kind offer. 👍 I'll find out in a week or so.
It may well have been my fault, that bottom wire retaining plate was missing and the wire was hanging on by a couple of strands and I did try a repair in situ. That probably damaged it. Lesson learned (again!).
👍👍👍
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The aftermarket switchgear arrived and was surprisingly decent. The only issues were:
- different wiring colours, but several of the black wires had thin tracer lines and I was able to match them;
- the wire length is longer, suitable for US bars. I pondered cutting and reattaching the connectors, but chickened out. It is currently coiled within the headlamp bowl. I'm hoping there is sufficient space to avoid it pressing any connections apart.
I took the bike for a short warm up ride, then failed to dial the carbs in any better on just the pilot screws.
- still lumpy idle below 1500rpm
- slight hesitation opening the throttle from low revs, then pulls ok.
I think my cam chain is still loose. At low revs there's a bit of chain lash noise. So gasket needed and I'll remove the tensioner to check if it is free. Hoping desperately it's not the primary chain, but with 40,000 miles on the bike, i guess it could be.
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I would appreciate more advice, please. I thought I'd give it another go on the carbs. I did a 25 mile run, to warm it up on the whole, a nice little ride. But, hesitation on a light throttle, before it pulls and idle is lumpy below 1500rpm.
So, I tried to adjust the carbs. I don't really detect a sweet spot on the pilot air screw. I started at 1 turn out and hesitation is apparent gently rolling on the throttle (less then 1/3 throttle). At 3/4 turns out of the air screw, the hesitation was worse, but the idle initially seemed, 'perhaps' smoother but very difficult to be sure. I can turn the screw all the way in on individual carbs and not really notice much difference at idle. Idle seems lumpy below 1500rpm even with the screw out from 3/4 to 2 1/2 turns. I think it is running on all 4cyls.
Any thoughts?
Slide adjustment? I'm wondering if the slides may not be seating fully. I thought they were when I had the carbs off to clean. I hear a clack from them going back down and it seems to be in unison.
Float height or stuck float(s)? I measured and adjusted to service manual spec. I measured from the rim just inside where the gasket seats, to the float, at the float position when the needle just gently starts to seat. There is nothing coming out of the carb overfow pipes. But might this be connected to the oil level issue below?
Pilot jet blocked again? But it does idle and starts OK without throttle when warmed up.
One other significant finding. The bike had just had an oil change. When I checked the oil, the level was fine and it was clean. I checked it again after my run and it is now half an inch over the upper line, with a slight emulsion and an odour not quite of pure oil. It seems thinner, but it was hot. There was dripping from the end of the valve cover breather pipe, which seemed almost clear, not really oily. Could this be fuel contaminating the oil? What could cause this? I did forget to turn the fuel tap off when I filled the tank and paid. Maybe 5mins at most.
Appreciate advice / commiserations/ encouragement! :)
P.s. my tyre stayed up, the back brake now works, as does the starter button! :D
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Are you comparing the change of oil levels whilst on the center stand on level ground on a cold engine?
Breather pipe might just be doing it's job venting off from a warm engine?
I would not panic just yet.
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Have you checked the float level height?
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Are you comparing the change of oil levels whilst on the center stand on level ground on a cold engine?
Breather pipe might just be doing it's job venting off from a warm engine?
I would not panic just yet.
It's a 750 Ted, it's a dry sump system, it has a seperate oil tank. You check level when engine hot. On a cold engine, there is a higher possibility the oil has sumped and not returned up to the oil tank.
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Forgot about the tank system - just trying to ascertain if the oil levels were checked in identical circumstances. If I do an oil change I fill it close to level, fire it up to ensure filter is full of oil then check it again & top up if needed.
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Yep, the oil checks were done on the centre stand. Sumping is a possibility. But I checked it first time within only a couple of days of it last being run. I'll change the oil before I start it next and see what it looks like. :)
Is it possible fuel can drain into the head without troubling the overflow pipes?
Odd Job, yes, I scrupulously checked the float heights, then rechecked, before reassembly. I could be doing it wrong, but I followed the two YouTube videos posted by Spanner Rash, on his CB750, which helped me understand the procedure in the Honda manual.
I think another carb cleaning day is in store...
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We did have a member here a while back who accidentally left his fuel tap on - the petrol drained into the sump iirc causing damage when he tried to start it.
I assume the petrol went into the inlet manifold via an open valve into the cylinder head / piston area - drained into the engine. Are you sure your fuel tap is closing fully?
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Ted, Yes, the tap seems OK, no leaks when I have the tank off. I did leave the tap open for about 5 minutes, when refuelling.
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Might be worth disconnecting the outlet - fitting some pipe to check if the valve is passing internally overnight.
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"Pilot jet blocked again? But it does idle and starts OK without throttle when warmed up."
Two elements to this circuit that can run you round in circles.
Assuming that the fuel jet isn't blocked, it can just flow full to that capacity without impediment. Its mitigated by the air supply which is modulated by the screw.
If this air route is blocked, then you'll see no response to changing positions, just that the idle mixture is fixed at any speed according to venturi vacuum only, so not full rich when starting but not low like it should be.
So it'll work in a fashion but without the idle mixture graduation it should be able to use in smooth tickover as will be permanently rich, not seen as you get higher revs as it acts normally there (idle jet is maximum flow) but lumpy when you try and let it idle.
This also forces you to use more slide lift just to keep it running (to counteract the rich idle mixture) and again keep chasing your tail with this in never being able to set a competent position for general running.
So very detailed clean and blow through/verification of air passages should bring these to working correctly.
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What kind of tap is fitted Martin? The double outlet with the small bowl underneath?
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"One other significant finding. The bike had just had an oil change. When I checked the oil, the level was fine and it was clean. I checked it again after my run and it is now half an inch over the upper line, with a slight emulsion and an odour not quite of pure oil. It seems thinner, but it was hot. There was dripping from the end of the valve cover breather pipe, which seemed almost clear, not really oily. Could this be fuel contaminating the oil? What could cause this? I did forget to turn the fuel tap off when I filled the tank and paid. Maybe 5mins at most."
Possible the fuel has diluted it, smell it to see and compare with fresh oil in can, smell wise. Unburnt petrol is easily picked up in aroma.
See also my post on idle jets, if run too rich there it'll soon wash some down the bores to give dilution too.
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For oil level on the 750, you can check it running as that's the true system level. If it shifts significantly after being left off overnight that would confirm "sumping" and need attention to oil pump seals. Not difficult on these as it's just sump off to get to the pump.
Dry sump system are usually checked this way generally.
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What kind of tap is fitted Martin? The double outlet with the small bowl underneath?
Hi, It is a single outlet pipe. Looks original.
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K2-K6, thanks.
I will take the carbs off and try again. I think i was too lazy first time round, not dismantling the upper part of the carbs. I've also bought David Silver's carb refurbish kits. I will compare with the current hardware in the carbs. I'd prefer to keep the original needles and jets, but after 46 years, I guess there's no guarantee they're original anyway. At 40,000 miles, if they are original, they're possibly due a change, but I won't rush into that if the existing parts look good.
After a day and a bit, there's no sign of the oil level dropping. May be too early to be certain. My Commando takes a couple of weeks. It smells oily. It seems thin, but I'm used to the Norton's 20W50! I'll check it against the 10W40 I bought today. I got a gasket set, so I can do the sump and look at the oil pump, if it starts to sump. I'll also now have a gasket for the cam chain tensioner, to check if that's actually moving.
Appreciate your input.
Martin
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On the first carb, I've removed the main jet and jet holder, but the needle jet is stuck in the carb body. How do you get the needle jet out?
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Needle jets need to be tapped out from the top with a pin punch the correct size.
Change the needles and needle jets with original Honda items and you'll cure the lumpy running below 1/3 throttle.
Good luck
Skoti.
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Martin, you probably are doing it correctly but I thought I'd ask anyway, you are setting the float heights with the bank of carbs standing upright in the vertical position, like a flag pole?
Non 750 carbs I know but the theory is the same on all CB SOHC/4 carbs I'm my attached link below.
http://www.sohc.co.uk/index.php/topic,23233.0.html
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Needle jets need to be tapped out from the top with a pin punch the correct size.
Change the needles and needle jets with original Honda items and you'll cure the lumpy running below 1/3 throttle.
Good luck
Skoti.
Thanks.
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Martin, you probably are doing it correctly but I thought I'd ask anyway, you are setting the float heights with the bank of carbs standing upright in the vertical position, like a flag pole?
Non 750 carbs I know but the theory is the same on all CB SOHC/4 carbs I'm my attached link below.
http://www.sohc.co.uk/index.php/topic,23233.0.html
Thanks for this. I was setting mine with a Vernier, carbs angled so that the tang just touched the valve, but didn't move it down. So I think the same result, but I'll check with your method this time.
On my 750 K6 carbs, the bowl rim casting is a different shape to your photos. They have a lip for a strong compression of the rubber bowl seal, plus a small flange at the side within that. I set the vernier tip on that small flange, rather than the seal lip. No idea if that's right. Makes just under 1mm difference.
So far I'm only on no.1 carb. I've found:
- The air screw didn't have a spring on it. It hadn't moved though, so not likely that's my issue.
- This time I've taken the carbs off the gantry. No.1 slide is stiff after the first 1/2 of its movement. There was a small patch of corrosion inside the slide cylinder (of the carb body). I've gently polished that area with Autosol. That's improved it a little. Am I OK to give it a little more of a polish. I'm holding off, as I'm concerned I may interfere with the 'vacuum' seal if I over-polish it, but a little more may give a smoother movement to the end of its run. The slide movements of the other 3 carbs are fine.
Thanks.
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Yes, on the 750 carbs the measurement is taken on the inner flange, not the outer lip.
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Thanks. 👍
You've all been very helpful. The manuals are OK, but it's great to get experienced input. I appreciate it, thank you.
Martin
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I've hit a problem on carb #4. I've been replacing the needles. On my version of the Keihins, this requires a 'stay plate' to be removed, so the plunger and top of the carb can be pulled out, revealing the needle. The stay plate is held in with two small x-head screws. One of these is seized. I have the right screwdrivers, but I now have very little grip on the head remaining. I soaked overnight with penetrating oil, but still no joy. I'm reluctant to clamp the slide in the vice, as this could distort it. There's no space to clamp the screw head. Out of ideas. Please, any suggestions?
The bike seems to be fighting me at the moment! ;D
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Any chance of boring a hole into wood block such that you can stand the sllide down into that, then you can really lean on the screw to get traction.
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Any of the screw sticking out of the bottom of the slide? I seem to recall they are slightly too long, if that's the case you could if all else fails drill the top off the screw and try and use a pair of pliers to turn the screw out from the bottom, the problem is probably the bottom of the screw has gone rusty, this won't allow the screw to go through the threads in the body, doing it from the bottom should mean the threads inside the body, which are usually clean will then just turn out of the body. Try and tighten the screw a little beforehand so any rusty threads are out of the body.
Other than that buy another slide.
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Maybe try a bit of gentle heat?
Could do with heat gun but probably safest in the oven.
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Heat gun, you want the surrounding metal to get hot, not all of it. If the screw expands faster than the slide it would stick harder.
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None of the screw is showing out the bottom. I didn't know I could still get hold of just the slide. Will look at that.
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They'll be a few members around with broken 750 carbs, I'm sure one will be able to source one if you ask. Just make sure you quote the number printed on the base, usually
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I put a punch upside down in the vice, sat the screw head on it, then drilled the screw out from the underneath face, tapped it for a larger screw and opened the stay plate hole a fraction. So that bit is sorted.
However, the carb's slide cylinder is quite badly corroded. It is a really stiff slide. Really stiff. So I have found the reason for my stiff throttle and unwillingness to self return. I touched it with some emery cloth and autosol and not much difference. So i hit it a bit harder. Better, but still quite a bit stiffer than 1-3. I've no idea if I've damaged the vacuum / air seal, could well have done. I took off as little as i could, but it was quite bad. I'll crack on at the weekend and then see if it runs OK.
I may need a new carb after all :-\ , I really hope not.
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They'll be a few members around with broken 750 carbs, I'm sure one will be able to source one if you ask. Just make sure you quote the number printed on the base, usually
Thanks. Hoping not, I'll soon find out!
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Ask on the site in the desperately seeking section and see if anyone has a spare carb body for that cylinder, you'll need the carb model number which will be stamped into the body somewhere, on the 500/550 it's on the mounting flange, usually 3 numbers and a letter. If you want cylinder 4 for example you must ask for number 4 carb to replace your existing one.
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👍
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In my carb rebuild kit there is a small o-ring and small washer. Can't for the life of me see where they go. Any ideas?
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In my carb rebuild kit there is a small o-ring and small washer. Can't for the life of me see where they go. Any ideas?
Carb sync port hole screws?
Edit... Or on the top of the carbs? Can you post a photo?
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Hope this comes through.
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Is there anything on the air screw, there's usually something on them but the parts book doesn't show it.
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Float bowl drain oring and inlet manifold vacuum screw? The prize is mine.
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Float bowl drain oring and inlet manifold vacuum screw? The prize is mine.
Thank you. Is that the screw that plugs the hole used for vacuum guages?
The prize is a trip to Essex to balance my carbs :D
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Except the float bowl sealing ring is shown as being alloy in the parts book.
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The carbs will be similar weights.😁 Apologies, overlooked it was a 750.
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👍
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Took the bike for a 20 miles spin. All went very well. I replaced the oil, and had removed and cleaned up the cam chain tensioner, which was seized, while the carbs were off. Properly adjusted, the bike now seems happy to idle at 1200rpm without clatter and so far as the carbs are concerned, it isn't hunting at idle at 1 turn out of the air screw and it pulls cleanly, rolling on the throttle. I changed the needle position to mid point (from 2nd groove up) and this has removed the hesitation. No sign of no.4 running any different to the other 3, but its slide movement is a little stiffer. Can live with that. The twistgrip now self returns to idle, not a snap back, more a smooth 1/2 second meander, but not a problem.
Bonus: I enjoy riding the bike. That's a huge relief! :)
Thanks for the advice. 👍
Martin
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Well done Martin, enjoy.
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Well done Martin, enjoy.
Thank you :)
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Nice one Martin! Very satisfying to get to the bottom of the niggles and get her running good. I still say with these old classics we are the carers, and modern bikes the owners.😀
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Nice work and good when you get a decent progression for your thinking and time spent working on it.
I really like the 750 motor for the torque it makes, especially the low down grunt just off idle. Very nice to ride I feel.
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It's the handling that's surprised me. From press reviews I was expecting soggy and vague. Not at all, so far. The rear is a bit under-sprung (I'm 170lbs). Even on max preload. The rear shocks were replaced a couple of years ago. Plus, I'm trying to work out some front end tramping. But dynamically, it goes where pointed with decent feedback. Inspires confidence.
Probably handles a little better than my '75 850 Commando, which has new Hagon shocks. The impression is it's not as quick accelerating. Possibly, that might only be because it is a smoother motor.
Comfortable riding position too. Very pleased, even if it's been making me work for the privilege!
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In my opinion anything handles better than an 850 commando, that elastic mounting system was a real dogmess
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It's funny that such store was given when I was originally riding these, with many work colleagues calling them crap etc, never thought they were bad handling as often projected that a brit framed bike was ultimately superior.
Key to many of these is to make sure the swing arm and headstock bearings are lubricated effectively and, if replaced, using the best solution available to give the least resistance and best locating methods.
Pretty nuetral in my view and experience, even when pushed as far as possible in their performance.
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The old Norton featherbed frame was way better than thesingle downtube Triumphs and BSA of the time hence the number of Tritons and such but when Triumph had the twin front tube they got a lot better as long as you kept the swingarm pivots good.
I went from an Enfield 250 of about 7hp to a 1959 T110 to a 62 T120 then i saw the light, literally, and went Honda 500 four, also worked in the bike trade from 75ish so watched the Japanese takeover, whilst the biggest breakthough was electrics the woked and oil that stayed inside reliably predictable handling was also there, probably due to consistency of parts