Clutch pressure plate uneven lift

Started by Steve_M90, September 03, 2018, 07:15:56 PM

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singleminded

#3
I looked at the clutch plate and found that a 3 degree misalignment between the centre bearing face and the outer part of the plate that bears on the top friction plate gave me 80 thou difference low to high,about 2mm.
I thought about how to check this on the bike and came up with the following which I knocked up out of scraps.
I found that the clutch was completely free at 70thou lift..
Larger photos are in the gallery under the general section.John

singleminded

Mine always lifted square as fer as I could tell..The thrust bearing I fitted has just cut it's way out of the plate though..I have seen another one that warped and the top of the bearing dome was not parallel to the plate which would cause uneven lifting..Have you tried assembling the plate/bearing and worm off the bike to see if the worm is squre to the face of the plate.. Or maybe the inside of the dome has worn unevenly..John

Steve_M90

I have a 1932 Model 90 with the clutch operating mechanism on the left hand side. Having reassembled my clutch, it is dragging. When I measure the lift (through the holes for the clutch stops) I have 3mm of lift at the top and <1mm at the bottom. I get these measurements whatever the orientation of the clutch sprocket. Everything looks normal - spring tension, plates, operating mech. The only thing which has changed is the thrust bearing. The cage of the one in situ (original?) has just failed by breaking into four equal pieces. I have bought a replacement which has same ID, smaller OD, same race diameter but smaller balls. It's not clear what caused this failure so this could be linked to my issue.

I think that the plate is being pulled out of true but I cannot find a reason. Any similar experiences or advice?

Thanks, Steve