cb550k3. Its alive after 26 years of snoozing.

[nairb]

So having done battles with the carbs for weeks I decided it could go for an mot.  Its not registered as historic vehicle yet so it helps with the paperwork at the GPO to have an MOT.
Well it did make it to the mot station but it was plain that all was not well.  The speedo became stuck at 20 mph and slowly went back to zero when stopped.  The rev counter also had very limited range.  So these will need to visit a clock repairer.

The major issue seems to be that the revs seem to be high compared to the speed.  There does not seem to be any obvious clutch slip as you pull way but by 5th gear the speed is about 40mph and the engine is revving too high for the speed.

I have had the bike from new so I know all the history.  Its done 42k miles on the original clutch.  I am wondering if I should replace the clutch plates and/or springs.  I cannot take all of the slack out of the clutch cable anymore either by adjusting the engine end or handlebar side.  Maybe after sitting unused for all those years the clutch plates are not serviceable anymore.

Is it clutch change time??
Ta
Nairb

[Johnwebley]

Not yet.

It should do about 11mph per thousand revs.

So at 60 it will be just over 5k.

Remember they have 4 small pistons whizzing up and down and in a typical Honda style need to rev.

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[McCabe-Thiele (Ted)]

I agree the clutch springs might be weakened but in my limited knowledge if the clutch has some free play then the only way to account for higher revs than expected at a given speed is due to clutch slip.

That said if the speedometer & rev counter are not reliable then you might not have any clutch slip - as you are no doubt aware it's usually easily felt by applying some power low down in the torque band and feeling if the acceleration matches the revs. I'm assuming you have not used fully synthetic engine oil that might just be too slippery for the wet clutch to operate as designed.

Not sure how much use the bike has had but am amazed it had not stuck through  lack of use  or has it been dismantled by your good self? Have you had to free off a stuck clutch after 26 years - the clutch on my XJ900 would stick over the winter 4 months of standing.

[K2-K6]

I've a "standard issue test" for clutch wear and ability to transmit:-

Get it pulling in third gear with throttle quite wide and give the clutch lever a little "ping" just so it lets the revs rise. It should immediately be able to grab and hold the torque as the clutch plates and springs try to bite again.

If it won't hold that then it's most likely too worn.

But you also need to check all the operating mechanisms are free and adjusted well first.

[McCabe-Thiele (Ted)]

I've a "standard issue test" for clutch wear and ability to transmit:-

Get it pulling in third gear with throttle quite wide and give the clutch lever a little "ping" just so it lets the revs rise. It should immediately be able to grab and hold the torque as the clutch plates and springs try to bite again.

If it won't hold that then it's most likely too worn.

But you also need to check all the operating mechanisms are free and adjusted well first.

I like that simple test with explanation.