I know nothing about M20's if that's the bike you have but on most bikes the clutch centre nuts are usually torqued to about 70lb/ft or just very tight. Could you fit a tab washer or spring washer under the nut? You could use loctite nut-lock if it still comes loose.
I had the same problem a couple of times with my AJS a while back and did just what Horror is suggesting. I fitted a thin spring washer under the nut and used plenty of thread lock solution just for good measure, it's never happened since.
Hi Jacco..It will stay done up if you tighten it sufficiently...Put the bike in gear, apply the back brake as hard as you can and then tighten it up. I've never experienced any problems with this nut using the method described.(I don't loctite them or use any other form of locking)..Ian
It's important that everything is in good condition. The thread on the mainshaft is unlikely to be damaged but the nut needs to be in good condition internally and not sloppy on the thread. Make sure that it's an original high-tensile part and that it isn't burred on the underside - worth flatting if that's the only problem, otherwise replace.
Ok....problem seems to be solved.had my first drive and stings seemed ok.....although i could not get the gearbox in 1st and 2nd ??......that was 1 , seconds....my chain came off. Opened new topic for that as I'm challenging the rear axle shaft setting now....do i miss some parts??
Cheers Jacco
Pls see new topic.
Thanks for the tool offer....Im in Netherlands....have a look later.
the clutch on one of mine came loose just managed to get it home with no clutch it turned out the taper in the clutch hub was worn a nos one cured the problem