AJS & Matchless Owners Club

Could anyone advise how tight the clutch centre nut should be please, 1964 G12 CSR. Many thanks

Sorry not really an answer, you should be able to find standard torque settings by bolt on the internet, mine are just done very tight (in know, a useless measurement) with a large spring washer and thread lock.

Half grunt for me

According to the service manual, one should avoid over-tightening the mainshaft nut.
Normal torque setting for a 5/8" bolt is 60 lbs-ft. I sugget using 50% of this value.
Clutch centre rides on conical splines and there is no hard restraint. Pushing the clutch centre up on the conical splines doesn't give the same feedback as prestressing a bolt, hence the caution.

- Knut

Over tightening of the centre nut will squash the stop-ends on the clutch centre splines which are relatively soft compared with the g/box shaft, which in turn means the nut will come loose and the clutch centre will eventually start to rub up against the gearbox out -put shaft. This is a common problem because of constant over tightening of the centre nut. The next time A clutch assembly is removed a check should be made of the clutch centre for any witness marks indicating the above problem has occurred. A classic sympton of the above is difficult gear changing similar to clutch drag. The clutch centres are quite an expensive item ( probably because of the machining involved) but the old centre can be dressed back to usability on a lathe. Worked for me.

Thanks to all for the replies. It has been overtightened and the centre was binding on the sleeve gear. The replacement centre has been machined differently and looks far more substantial, it gives a positive 'bottomed out' feel when fitted. New spring washer and nut fitted and torqued to 30 lbs-foot. Fingers crossed.