Honda-SOHC
SOHC.co.uk Forums => CB750 => Topic started by: Pauarc on June 11, 2023, 10:02:58 AM
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Should you soak new clutch before you install them
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It's reccomended
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I have now fitted new EBC clutch plates (ck1133). I have also checked steel plates for Warpage (I lay them on a sheet of glass) no Warpage I could measure with a feeler gauge. Also have put putoline S4 mineral oil 10w40 in bike.The clutch still drags I have adjusted bolt in then out 1/4 turn 25 mm free play on leaver I have even tried adjusting bolt with no slack clutch plates seem to be sticking together any ideas
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There's not that much margin to lift the plates clear on them, every little bit counts in reality.
Suggest a set routine to put everything toward maximum lift to see what you get;- disconnect cable first, turn centre adjust screw all the way in to feel it touch down on the lift mechanism, then back out just a fag paper amount to only just "untouch" it if that makes sense.
That should have the operating arm at about 7/8 o'clock point without the cable connected to it.
Now fit cable and set slack at lever to 10mm at lever end, check that you can feel no tension in cable when released to make sure it's not now holding the operating mech in contact with plates.
Try it now to see what it does.
If the clutch heats up during use, then the thrust bearing moves away from the mechanism (you get more slack in the lever) so that's not a risk.
If, when, the plates wear though it will move clutch pack closer to mechanism and may eventually slip if not checked periodically through bedding new plates in.
In other words, if this is successful, go back and check again mech clearance with that centre screw in reasonable mileage to avoid it being just a little too tight.
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I will try that at weekend I have tried it in different ways but will have a go that way
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Just a thought could it be the oil any suggestions on that
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Just a thought could it be the oil any suggestions on that
Difficult to answer, and of course there are many opinions too ;D
The oil is, in an ideal world, trying to cling to components, but the clutch is designed to get it out of the way. As the clutch closes it's designed to squeegee the oil out from the friction area via the various slots in the fibre plates and with centrifugal dispersion to evacuate the oil and take torque drive through it.
When you open it with lever the oil will obviously go back in again, if oil is cold then the viscosity will increase the drag on the plates, one to another. Worth checking if there's a difference stone cold in comparison to up to temp/hot running.
If different, you could attribute that to viscosity change, but not much you can do about it. It would give you a reason partly though. A thinner oil could be used potentially, they are designed to run 30 viscosity hot from their tolerancing, in purest design terms. When contemporary though, my experience was to run them on 20/50 as using it pretty hard, also big que into race meetings they'd get very hot. That's allowable in Honda specs too, but didn't give any memorable problems in regard to clutch operation.
The method I've given above should give the absolute maximum lift attainable within the components used. It'll be a worthwhile benchmark to at least see what you think of it then.
Interesting to hear if that method gives you anything in the way of measurable improvements.
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Do you have a double steel plate in the stack ?
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I have no double steel plate what would this do
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It was an upgrade that was fitted to all K6's. Maybe you don't have a K6 clutch and it is from another 750 ?
Is your clutch fitted with the correct springs ? Two types of springs used on the 750K ;)
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Do you have your inner and outer located correctly. It should fit together like this
[attachimg=1]
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If it is fitted a quarter of a turn, then it is wrong as per picture
[attachimg=1]
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And your last plate has wider tabs than the rest of the plates and this is a picture of the last friction plate.
[attachimg=1]
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My bike is a Honda CB750k2 1975 all straight plates
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This was before I fitted new chork plates
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So you have a K2 clutch that was fitted to the UK K2 from 1972 to 1974 .
Your bike must have been registered in 1975 but, was it manufactured in late 1974 ? If so the clutch components you have in the picture are correct.
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Now we are getting somewhere. Your springs should be 35.50 mm to 36.00 mm in length and those steel plates need a good clean, if you haven't already done so. ;)
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Before I fitted new plates I put the steel plates in a ultrasonic cleaner springs are new
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The steel plates have a covering of dimples, these dimples trap oil and need to be very clean.
Did you put all the steel plates in with the flat side to the engine and the beveled edge facing out ?
Just because the springs fitted are new, there are two types so, you need the correct length ones as mentioned before ;)
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I just checked the old ones they are 31.5 mm the new ones are 31.9mm I made a note and yes flat side in and bevelled side out.
this is the length off springs in the manual I have
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The shorter spring was used in the 750K0, K1, and some early K2's. Then it was superseded to the longer spring with a smaller diameter coil. Early spring at the top later at the bottom in the picture. The longer one just means a smoother clutch.[attachimg=1]
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spend a bit of time putting together a K2 clutch so you can see the stack measurements. Much easier to build the clutch up on the bench and then put it in the engine. You should end up with a stack at 37mm
You can pull the clutch together using washers on the springs and then you can see what is going on.
[attachimg=1]
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[attachimg=1]
[attachimg=2]
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One thing i forgot to ask, what was wrong with your clutch in the first place ?
Do you have a thin washer behind the basket ? and the thick keyed washer in front of the basket ?
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The clutch drag a bit before and gear change was clunky old plates were hard not any better with new plates no thin washer that I can remember but there was a thick washer
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I have just set central nut as you suggested have not tried yet as out today
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Some good details and specifications there from Graham.
Adjustment looks reasonable from arm position, it's just trying to bring maximum lift that can be attained with the lever/cable etc by adjustment to very small gaps in each stage.
Lever end free movement is in the manual at 10~25 mm, with that set to minimum @ 10mm it should reach the largest lift space possible on the plates/clutch pack and give the least drag in operation.
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Some good details and specifications there from Graham.
Adjustment looks reasonable from arm position, it's just trying to bring maximum lift that can be attained with the lever/cable etc by adjustment to very small gaps in each stage.
Lever end free movement is in the manual at 10~25 mm, with that set to minimum @ 10mm it should reach the largest lift space possible on the plates/clutch pack and give the least drag in operation.
There is something strange going on. I have built a shed full of K2 clutches over the 32 years in the engine business and it is one of the easiest ones out of the 750 range. ;)
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If the fin washer is missing behind basket could this effect the clutch I can’t remember seeing it
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I would not know as i have never fitted a clutch without one. It is listed as a thrust washer 90458-506-810 ;)
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When you fit keyed washer should it have be loose on shaft I have douts the fin washer was there I think I am going to take the clutch out to find out if it’s there
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Just when for a test run to try clutch adjustment a bit better cold but worse when hot 🥵 could it be the oil getting to sticky when hot in the 70s I used 20/50? Any thoughts it has putoline s4 mineral oil 10w40 in now
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Just when for a test run to try clutch adjustment a bit better cold but worse when hot 🥵 could it be the oil getting to sticky when hot in the 70s I used 20/50? Any thoughts it has putoline s4 mineral oil 10w40 in now
The oil gets thinner when hot, would be unusual to have a change in that to make it worse as ordinarily the clutch works more consistently when warmed.
It may be wise to remove, inspect and quantify the thrust washers etc to establish if anything is out of order there as characteristics seem odd.
Before any removal it would be worth pulling and pushing the clutch assembly in and out in order to assess if there's any/much end float on there. This is what the thrust washers etc are trying to control to give repeatability in clutch operation.
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Now I have decided that I’m going to remove clutch and see if I can find something I will see if there’s any end float
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I have removed clutch today before I undone central bolts there was slight in and out movement so took out plate stack which 36.5mm in total also springs out 35.5 long most have noted down wrong so in front of basket the spiled washer I can’t find a thing washer where should it be I have put back together maybe a little better no free play in central nut just to try
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The thin thrust washer is between the bearing and the basket.
[attachimg=1]
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I am trying to work out where on the shaft that is have I got to remove central shaft where the basket sits on?
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Pic from manual
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It just goes on shaft first before putting the clutch basket on, located between back of clutch and bearing.
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Don't believe a manual. It is number 18 in this link >>> https://www.cmsnl.com/honda-cb750k2-four-england_model14363/partslist/E18.html
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I have added some pictures I must be missing something I have a 25mm shim
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I am not sure what the washer is in picture number 3 you have posted. Can you post a picture of that washer on its own and not on the shaft.
I have just fitted a shaft to a set of crank cases and the thrust washer i was on about is the other side of the bearing so, forget about that one as, you will not even see if on a clutch change
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Shim washer
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Have you got this fitted?
https://www.cmsnl.com/honda-cb750k2-four-england_model14363/washer-spline25mm_90432300303/
There is also this fitted between the clutch basket and the bearing.
https://www.cmsnl.com/honda-cb750k2-four-england_model14363/thrust-washer_90458506810/
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Shim washer
I am not sure were this shim washer has come from. Once everything is in you have a bevelled washer with outside stamped on it, then the clutch locking washer and then the locking nut.
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This is the clutch that should be fitted to your K2 >> https://www.cmsnl.com/honda-cb750k4-four-1974-usa_model482/partslist/E++09.html
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Why would a K4 clutch be fitted in a K2?
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I just can’t workout where you would fit a 25mm shim wash I only put it there to try to find where it would go I have the keyed washer that goes where I tried that shim washer
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Part 18 on this diagram
https://images.cmsnl.com/img/partslists/honda-cb750k2-four-england-transmission_bigma000039e18_1229.gif
Why Honda decided to list it on that diagram is beyond me, surely the clutch page would have been far better.
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Part 18 on this diagram
https://images.cmsnl.com/img/partslists/honda-cb750k2-four-england-transmission_bigma000039e18_1229.gif
Why Honda decided to list it on that diagram is beyond me, surely the clutch page would have been far better.
That washer is deep inside the engine Ken and it is not a K2 engine it is a K2 bike with a K4 engine.
[attachimg=1]
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I just can’t workout where you would fit a 25mm shim wash I only put it there to try to find where it would go I have the keyed washer that goes where I tried that shim washer
I can not see why you would have this washer in the clutch area. Assemble the clutch back in the engine without it and see if it makes a difference ;)
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This is my cb750k2 clutch 1975
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Has this engine been apart ? And this shim washer is from inside the gear box ?
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No not the bottom end that I know off I have done top end
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Only got shim because it was I thought it was missing from clutch shaft?
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No not the bottom end that I know off I have done top end
OK, that shim washer looks to be all silvery and new. Most washers in the gearbox and clutch have a black coat to them.
All i can suggest to put the clutch back in without that shim washer .
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Only got shim because it was I thought it was missing from clutch shaft?
Why would you put something in that should not be there .
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I am going to put it back together as it was with no shim I will see how clutch is with smallest clearance
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Clutch seems to be working better now did about 30miles seem to get worse when it gets hotter could it be oil what oil do people use is it worth trying 20w50?
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Nope, stick to 10w40, you need the thin at cold to lube the top end
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I always run 20/50 high zinc in the summer ;)
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What does the high zinc do
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What does the high zinc do
Zinc "zddp" is only really active when the oil film breaks down due to very high pressure. It protects against cold weld/spalling in metal to metal contact areas such as cam lobes and followers, also gear teeth faces etc.
Not so relevant to crankshaft, pistons etc.
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Too much Zinc can clog the engine oil paths in the right concentration it helps protect camshaft parts.
STP contains zinc.
Millers Oils recommends an optimum amount between 1000 – 1400 ppm of ZDDP. Too little won't offer enough anti-wear protection, and too much will not provide increased levels of protection, but can actually create friction and increase wear due to the 'over-plating' of components.
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Can you add zinc to the oil
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Can you add zinc to the oil
STP would do it in the correct proportion trouble is you do not know the base content before you add it - in reality all good branded oils probably have the right amount as part of the oil specification.
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Shouldn't be any real need to add anything to a decent spec oil for these engine, theyre not too demanding in the various different aspects of protecting all the components.
By far the most critical is oil condition, specifically dilution by excess fueling from too much choke and short runs. Other than that, you'll be very unlikely to run into any problem.
For assurance, start by finding out what the zddp level is of the oil you've used.
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Not sure if it has zddp
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Difficult to find a spec for that oil that says much, either way in respect of zddp presence.
It's definitely a frustrating part of how oil companies promote their product.
Very loosely speaking, any oil used or specified for modern engine that have anything in tbe way of exhaust gas treatment will usually involve lowered content of zinc formulation. This because of longevity in those component with regard to sensitivity to zinc byproduct. They do seem to miss though that a good engine can burn very very little engine oil, making it's presence in exhaust likely extremely low.
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Not sure if it has zddp
Most branded modern oils will contain Zinc as a base line ingredient if you go for something like Miller, Manol, Shell, Castrol, Motul, Mobil, Elf, Silcolene, possibly even Comma they all meet the modern specifications even when not fully synthetic.
Or buy cheap Asda Mineral then add STP as per instructions on the can.
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I have now changed oil to motul 3000 20w50 so much better now
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I have now changed oil to motul 3000 20w50 so much better now
I did advise 20/50 mineral high zinc weeks ago :o
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I have now changed oil to motul 3000 20w50 so much better now
That's what I'm putting in my bike tomorrow after I've painted a couple of parts first.
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Yes trigger should have listened
the putoline 10w40 was no good for my CB750k
Just now I like to get tikover down to about 1000 steady?mainjet 120 slow 40
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I have now changed oil to motul 3000 20w50 so much better now
That's what I'm putting in my bike tomorrow after I've painted a couple of parts first.
No good in a 400 engine. You need to use 10w/40 or 15w/40 mineral oil ;)
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Yes trigger should have listened
the putoline 10w40 was no good for my CB750k
Just now I like to get tikover down to about 1000 steady?mainjet 120 slow 40
1000 rpm is too low and why have you got 120 main jets in ?
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No good in a 400 engine. You need to use 10w/40 or 15w/40 mineral oil ;)
Thanks for this Graham. Next time I'll get that instead, surely nothing will go bang using it in one change though? :-\
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No good in a 400 engine. You need to use 10w/40 or 15w/40 mineral oil ;)
Thanks for this Graham. Next time I'll get that instead, surely nothing will go bang using it in one change though? :-\
Too thick for a 400 gear box pump ;)
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Too thick for a 400 gear box pump ;)
I'd best go on hold a couple of days until I get some then! BTW I've been using any old four stroke M/C oil these past five years, hope I haven't done any harm. :o
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Yes trigger should have listened
the putoline 10w40 was no good for my CB750k
Just now I like to get tikover down to about 1000 steady?mainjet 120 slow 40
1000 rpm is too low and why have you got 120 main jets in ?
Trigger,
This is an interesting post and got me searching through the Honda workshop manual. 120 jets were on the 750s K0 to K4. K5 no mention of a change, but K6 are specified as 105 main jets. Are the carbs different on a K6? Do you know how they differ?
I have my idle set higher on my old bikes. I don't have any justification. It just feels kinder to avoid chugging and get a bit more oil pressure. My CB750K6 is set at between 1200 and 1400rpm. But the Honda manual does say 850 to 1,000rpm. Could you explain why you would avoid 1,000rpm?
Thank you.
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The Main jets on a 750K started out at 125 and then Honda dropped them to 120 on the early 750K0's. I have lost count on how many different carb numbers that were fitted to the 750's over the 10 year period.
The early 750's had 300 exhausts which have less back pressure than the 341's so, the jet range was 125 down to 120 but, some had 110 in the K1. Then the 341's were fitted to the K2 onwards that had 110 as standard in the UK. And the K2 was sold in the UK from August 1972 to 1975. Don't know about the K3, K4, K5 as these were USA bikes.
And then the K6 came out in the UK with 110 or 105 jets.
I have also lost count on how many different needle numbers across the 750 range and can be a struggle to find the sweet spot sometimes. My own K6 runs sweet with 110 with a little discolour on the plugs, pulls well and gets a little scary over 110 mph.
I always set the RPM at 1150 rpm as this puts less strain on the engine. Never had a 750 that was happy at under 900 rpm.
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Thanks for explaining Trigger.
I recently replaced 2 of my K6's carbs with better condition ones, bought as a bank off ebay, complete with gantry. I replaced the brassware, so all 4 were consistent with 105 mains. Relived the jetting is the only difference on the later bikes.
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Thanks for explaining Trigger.
I recently replaced 2 of my K6's carbs with better condition ones, bought as a bank off ebay, complete with gantry. I replaced the brassware, so all 4 were consistent with 105 mains. Relived the jetting is the only difference on the later bikes.
Are the carbs all the same number stamps ? No need to replace the brass, just used the original brassware once cleaned .
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No good in a 400 engine. You need to use 10w/40 or 15w/40 mineral oil ;)
Thanks for this Graham. Next time I'll get that instead, surely nothing will go bang using it in one change though? :-\
Too thick for a 400 gear box pump ;)
Ultimately detrimental to hi-vo type drive chain primary too.
Natural development state of 5 viscosity oil, survive in these engines at outer limits with thicker oils with functioning and compromised lifing because of this.
Related to flushing of internal bearing surfaces via oil throughput to replenish oil film, take away heat and not fail the shear properties of the oil. Used in much higher torque installation with ATF oil in plsce, will easily reach 200,000 miles or more, but lucky to see 50,000 in these engine for practical service life.
No suggestion to use ATF ;D but you can see the balance being struck with the specified engine oil they ask for.
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Interesting comments about multi grade oil
I always thought the lowest number was for cold viscosity,
And as such would get pumped around a cold engine easier to get oil to bearing during initial start,
The larger number is the hot running thickness,
But, am I correct??
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Essentially yes but viscosity is not quite the same as thickness the term iirc only applies to fluids.
Thickness is an easy visualisation if you compared water with treacle.
The visual comparison starts to fall apart when you see how much thinner oil is when draining from a hot sump.
I think of the higher figure being a measurement of the oils ability to perform as a lubricating film at high engine temperatures - the lower figure being the performance at lower temperatures.
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Thanks Ted,so for an old worn motor, like a 1960s Mini,a 50 grade is OK
For a modern tight clearance motor, a 5 is OK for cold starts
So,would a 5 x 40 be ideal for our sohc motors?
If no,why?
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I think for 500s it's the same as 750s, the lowest viscosity recommended by Honda, is 10W40. So you risk the oil being too thin as the motor warms up, particularly during warm weather.
I take the view, oil is cheaper than a re-build.
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Honda recommend 10/40 or 20/50 on the CB750 ;)
As your decal states >>> https://www.ebay.co.uk/itm/193883042558?hash=item2d245472fe:g:iVIAAOSwBLlU-OiF
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Thanks Ted,so for an old worn motor, like a 1960s Mini,a 50 grade is OK
For a modern tight clearance motor, a 5 is OK for cold starts
So,would a 5 x 40 be ideal for our sohc motors?
If no,why?
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In old Minis we used the old spec oils like Duckhams 20/50 as the engines like a motor cycle have to lubricate the engine, gearbox & diff so an oil that worked at high temperatures was essential.
It was a common thing that if you drove a Mini on long motorway distances like I did from Derby to Bradford they would sometimes become stuck in top gear - even on models with oil coolers - the problem would go away if you had a cuppa at the services.
When Vauxhall built the first of the FWD Cavaliers & Astras gearbox layshaft rattles were an issue that were solved by using ATF in the gearbox instead of the normal gear oil. I understand that they did modify the gearboxes in later builds but the fix did work.
Many modern cars use 0W/30 engine oils. With ATF's it is pretty much accepted that the modern ATF oils are backward convertible so a gearbox designed to use Dexron 2 can now use Dexron 3 or 4 even. With ATF's vehicle manufacturers were very specific about using the manufacturers brand e.g. in a Nissan model use AT-Matic J only stating that deviation would invalidate any warranty. Happily this sort of Pseudoscience is a thing of the past with a bit more honesty about the ingredients with multi use fluids by well regarded manufacturers.
For some reason acceptance of a modern synthetic diesel engine oil being suitable for a diesel engine designed back in 1985 is met with scepticism.
I do not have enough knowledge & long term experience of sohc engines to advise you if a 5W/40 oil would be suitable - I suspect that grade would be fully synthetic so probably no one has done the testing & research to find a true answer based on rigorous testing.
In reality my experience on different oil brands/grades is anecdotal - we read the adverts & technical specifications and are swayed with a term like contains Zinc or PTFE etc we make choices that suit our wallet and personal preference's. As has been said before any oil is better than none.
Reverting back to original Honda engine oils as per old handbooks etc is based on technology that is now 50 or more years old but no one I suspect has explored if a more modern oils are better or backwards convertible across the range.
The idea that a modern synthetic engine oil is worse for your engine than one designed on synthetic technology I find very hard to accept.
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I used to use BP VF7 back in the day, loved that oil. It had so much cleaning detergent in it that working inside the engine was a treat, completely clean inside, no staining of the alloy inside at all, whereas engine run on Duckhams were black inside, never a big fan of Duckhams, preferred Castrol GTX if I couldn't get VF7.
Seem to recall VF7 was either 5/30 or 10/30.
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When working in the 70's we used silkolene, which we got from Popes in Bristol who were a pushbike shop but also the main Suzuki spares dealer for the sothwest and used to buy an artic load of oil at a time in 5 gall drums
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When working in the 70's we used silkolene, which we got from Popes in Bristol who were a pushbike shop but also the main Suzuki spares dealer for the sothwest and used to buy an artic load of oil at a time in 5 gall drums
Back in the 1970's Silkolene oil based in Belper was good value for money - all made from waste oil collected from mostly local garages - early re-cycling in action.
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I have. been thinking of changing the main jets to 110 they turned up today
Exhaust are hm341, carbs are 657b, needle set in middle, compression all around 160psi has just had top end rebuild new rings valves re ground, dynas ignition so no points
Carb sync with carbtune pro main jet was 120 slow 40 air screw 1and 1/2 out
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I have. been thinking of changing the main jets to 110 they turned up today
Exhaust are hm341, carbs are 657b, needle set in middle, compression all around 160psi has just had top end rebuild new rings valves re ground, dynas ignition so no points
Carb sync with carbtune pro main jet was 120 slow 40 air screw 1and 1/2 out
A little low psi. Was it rebored ?
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160 psi sounds pretty healthy to me - what is the original 150-170 psi?
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Did you remember to open the throttle fully when do the compression test?
A lot forget or don't know to do that.
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No rebore std rings bore was ok
carb not on bike when checked
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Engine cold?
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Yes cold and no oil
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Thanks Ted,so for an old worn motor, like a 1960s Mini,a 50 grade is OK
For a modern tight clearance motor, a 5 is OK for cold starts
So,would a 5 x 40 be ideal for our sohc motors?
If no,why?
Sent from my SM-A546E using Tapatalk
.........
I do not have enough knowledge & long term experience of sohc engines to advise you if a 5W/40 oil would be suitable - I suspect that grade would be fully synthetic so probably no one has done the testing & research to find a true answer based on rigorous testing.
In reality my experience on different oil brands/grades is anecdotal - we read the adverts & technical specifications and are swayed with a term like contains Zinc or PTFE etc we make choices that suit our wallet and personal preference's. As has been said before any oil is better than none.
Reverting back to original Honda engine oils as per old handbooks etc is based on technology that is now 50 or more years old but no one I suspect has explored if a more modern oils are better or backwards convertible across the range.
The idea that a modern synthetic engine oil is worse for your engine than one designed on synthetic technology I find very hard to accept.
Ted, I'm a member of the Access Norton forum. Some research was done on oils. See the link: https://www.accessnorton.com/Oil-Tests/NortonOil.php
Even if you only look at the first table, half way down, you can see the difference between Royal Purple HPS 20W50 and their HPS 10W40, is an increase in friction and heat, as tested. Just makes me wary of using oil outside the original spec.
I'm not a scientist, nor engineer, so I tend to play it safe. The key thing I find persuasive is, motors manufactured in the '70s used the design, materials and mass manufacturing technologies of their day. Modern oils may well be better manufactured and have superior additives, but the 1970s engines (even before allowing for 50 years of wear) have run for their lives happily using oils in the ranges specified by the manufacturer and were designed using materials, oil pressures, temperature ranges and moving parts tolerances specifically for those oils.
Only my view, I wouldn't be anti synthetic or semi-synth oil use in a freshly (properly) rebuilt motor, provided it is the right spec (viscosity and for use in wet / semi wet clutches), e.g. 10W40 MA01. I'd personally, be a bit more wary of using synthetic in an unknown / high mileage motor (sadly, mine is in that category!). My concern would be whether there's any risk the detergents pull out a few decades of sludge and do damage, before being filtered out. I wouldn't use 5Wxx.
So, I play it safe, stick to the Honda recommendation and listen to the corroborated, long term experience of other owners. But, I'm not knowledgeable or rich enough to experiment myself. :)
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Yes cold and no oil
👍
So will be higher, especially once run in. Did you do the engine work yourself or use someone? I may need someone this winter.
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Yes I have always worked on all my bike since the 70s away Honda (cb250,cb360,cb400,cb550 cb750 k7 cb750f2n and now CB750k2)
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👍
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In the 70s and 80s I used Duckham 20/50 or Castrol GTX20/50 and had no problems
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Thanks for explaining Trigger.
I recently replaced 2 of my K6's carbs with better condition ones, bought as a bank off ebay, complete with gantry. I replaced the brassware, so all 4 were consistent with 105 mains. Relived the jetting is the only difference on the later bikes.
Are the carbs all the same number stamps ? No need to replace the brass, just used the original brassware once cleaned .
Trigger, where do I find number stamps? Can't see anything on one of the carbs I removed!
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Thanks for explaining Trigger.
I recently replaced 2 of my K6's carbs with better condition ones, bought as a bank off ebay, complete with gantry. I replaced the brassware, so all 4 were consistent with 105 mains. Relived the jetting is the only difference on the later bikes.
Are the carbs all the same number stamps ? No need to replace the brass, just used the original brassware once cleaned .
Trigger, where do I find number stamps? Can't see anything on one of the carbs I removed!
Just by the port screw
[attachimg=1]
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Trigger, where do I find number stamps? Can't see anything on one of the carbs I removed!
Just by the port screw
So, I now have 2 x '086A', which came with the bike and are on cyls 2 and 3. My replacements were 2 x '657B'. They are on cyls 1 and 4. If I've got the same jets and needles across all 4, should I be ok?
I've done over 500 miles with them so far. Cyl 4 seems to be running spot on (perfect spark plug). Cyl 1 is a bit sooty though, but I was thinking this is due to my head leak, which I'm aiming to fix this winter. I could go with the 657B carbs on all 4, but the two 086As I swapped out, are beyond redemption. Any knowhow on what the difference is between the two sets of carbs?
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It's OK. Answered my own question. They are interchangeable.