Carbs Install

[K2-K6]

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. 

[Martin6]

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"!

[Martin6]

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.

[Martin6]

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

[Nurse Julie]

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.

[Martin6]

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.

[Nurse Julie]

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 .

[Johnny4428]

Good job Julie. Looks like could do with a bit of a clean.😜

[Martin6]

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. 

[Martin6]

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.

[K2-K6]

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.

[Martin6]

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. 

[Martin6]

Happy with the run  . Not happy with the corroded spring on the starter button. A Google search took me to Julie's ebay store. Replacement on order. 

[Martin6]

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?

[Nurse Julie]

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 😁😁😁😁