Clutch Drag When Cold

[Commuter]

A post script: I took the sump plate off and found that I literally had to split the gasket so that both mating surfaces were left with gasket stuck to them.... that took some really careful cleaning off. The screen itself was absolutely trashed and may as well not have been there at all since it would have been bypassing through the holes in it. Oh happy days!The clutch was undamaged and cleaned up ok , the plates werent warped in any way. I did find that someone might have "race tuned " it since the springs free length was in excess of 37mm. I am not certain what new ones are but old ones need to be 34mm minimum. 3mm seems an aweful lot of shrinkage. This might tie in with the over jetted carb and the 31 tooth back sprocket. On the plus side, everything about the bike does tie in with the low miles on the clock. The swing arm spindle comes straight out , has no play on it at all and has the original bushes in it.

Having reassembled everything and made sure that I use the right grade of oil, The situation with the clutch operation and the clutch drag was very slightly better but still not right. I dropped the oil again and took the clutch to bits. I could find nothing at all wrong with anything and so I started to look at my clutch springs. They appeared to be quite short and not very "squashy" I also looked very carefully at the plain plates and pressure plate whereupon I noticed that although they were quite flat and not warped ,there was slight effects of uneven wear concentrically. With the clutch in pieces but everything else roughly where it should be( ie tank and cable location), I tried the clutch lever operation and found that there is very little or no roughness or resistance meaning that the cable is routed correctly and not damaged or trapped internally. I ordered new plain plates and friction pales and new springs. The new springs are a revelation: they are about 45 mm free length and made out of 2mm wire instead of the old ones being 2.6 mm wire and just 37mm free length. They are also more squashy. Having reassembled everything with new plates, and springs, having soaked the friction plates for 24 hours beforehand, I ran up the engine and for the first time ever , managed to put the bike in and out of first gear and into neutral with total ease. The clutch operation is much lighter too. I guess that what had happened was that there had been this concentric wearing of the clutch plates sometime ago and possibly someone using the wrong oil and the clutch had slipped and so somebody fitted "racing " clutch springs. No need for a hydraulic clutch, over adjustment of cable orusing the engine kill to select neutral. Putting the bike into gear from neutral is no longer accompanied by a crunching noise since the clutch now releases. I think that had I not chased these issues with the clutch quite so relentlessly, I wouldnt have realised that the issue was a combination of issues. rather than just one thing.
Handlebar cable adjuster bent out of true by around 5 degrees.
Clutch cable kinked and not routed properly
Clutch worm over adjusted to minimise any cable play
Friction plates appear to be contaminated by use of the wrong oil
Plain plates worn concentrically but not axialy warped
Clutch springs overly heavy for street use.

The new clutch plain plates have a micro- dimpled appearance which the suppliers claim is for oil retention. The new clutch springs must need to be pushed into position in order to get the threads to engage with the clutch drum. The clutch centre and the clutch drum showed very very light slotting wear which I was able to dress out with a needle file and the clutch bearings are all sound.

Overall, my early 650B now has the same clutch operation as my later 650S had and so I am happy.

 

[bosco659]

Having reassembled everything and made sure that I use the right grade of oil, The situation with the clutch operation and the clutch drag was very slightly better but still not right. I dropped the oil again and took the clutch to bits. I could find nothing at all wrong with anything and so I started to look at my clutch springs. They appeared to be quite short and not very "squashy" I also looked very carefully at the plain plates and pressure plate whereupon I noticed that although they were quite flat and not warped ,there was slight effects of uneven wear concentrically. With the clutch in pieces but everything else roughly where it should be( ie tank and cable location), I tried the clutch lever operation and found that there is very little or no roughness or resistance meaning that the cable is routed correctly and not damaged or trapped internally. I ordered new plain plates and friction pales and new springs. The new springs are a revelation: they are about 45 mm free length and made out of 2mm wire instead of the old ones being 2.6 mm wire and just 37mm free length. They are also more squashy. Having reassembled everything with new plates, and springs, having soaked the friction plates for 24 hours beforehand, I ran up the engine and for the first time ever , managed to put the bike in and out of first gear and into neutral with total ease. The clutch operation is much lighter too. I guess that what had happened was that there had been this concentric wearing of the clutch plates sometime ago and possibly someone using the wrong oil and the clutch had slipped and so somebody fitted "racing " clutch springs. No need for a hydraulic clutch, over adjustment of cable orusing the engine kill to select neutral. Putting the bike into gear from neutral is no longer accompanied by a crunching noise since the clutch now releases. I think that had I not chased these issues with the clutch quite so relentlessly, I wouldnt have realised that the issue was a combination of issues. rather than just one thing.
Handlebar cable adjuster bent out of true by around 5 degrees.
Clutch cable kinked and not routed properly
Clutch worm over adjusted to minimise any cable play
Friction plates appear to be contaminated by use of the wrong oil
Plain plates worn concentrically but not axialy warped
Clutch springs overly heavy for street use.

The new clutch plain plates have a micro- dimpled appearance which the suppliers claim is for oil retention. The new clutch springs must need to be pushed into position in order to get the threads to engage with the clutch drum. The clutch centre and the clutch drum showed very very light slotting wear which I was able to dress out with a needle file and the clutch bearings are all sound.

Overall, my early 650B now has the same clutch operation as my later 650S had and so I am happy.

That’s great you’ve solved your problem. Interesting comments on the dimples on the plates. Did you buy OEM plates or aftermarket?

 

[Commuter]

That’s great you’ve solved your problem. Interesting comments on the dimples on the plates. Did you buy OEM plates or aftermarket?

Aftermarket