AMC Clutch - M31. What the ........????

[Greybeard]

A quick update. After ordering all the parts needed I stripped the G80 by way of preparation. The rubbers in that clutch look fine and I reckon could be left to carry on until well after my 'sell by' date As the new parts are cheap enough to be regarded as practically service items and the jobs already half-done, the new ones will be fitted anyway.
Out of interest, I've used ATF in this chaincase since I restored the bike way back in the early 90s. Perhaps its kinder to rubber than other oils As Bigwol says, it could well be just natural ageing, some rubbers lasting better than others - elastic bands never seem to last as long as they used to, though knicker leg elastic appears to be as resilient as ever
If the Spares folk work with their usual, excellent level of efficiency, everything should be back to normal by tomorrow evening and I'll have to find another job to do. I suppose I could make a start on fitting the new rear plunger springs to the Golden Flash - theyve been on the shelf for over a year now

Steve

[Mick D]

Hi

If there's nothing wrong with the existing rubbers I'd be tempted to leave well alone, you can be fairly sure they are compatible with ATF, not something you can say about any replacement ones.

Regards Mick

[robcurrie]

Steve, if you're looking for something to do while you wait for the rubbers, you can make a tool to fit them. 😁

Rob C

[Pharisee]

I replaced the rubbers in my AMC clutch last year as they looked a bit 'soggy' (not as bad as yours, though!). Having cleaned all the old rubber out and having got a new set of rubbers from AMOC Spares, I set about replacing them. I didn't have a spare main shaft to hold the centre part so I cut a piece of steel 'gauge plate' to fit in the splines so I could hold it in the vice. I thought I was being clever and lubricated the centre hub and rubbers with red rubber grease. That was a mistake... As I compressed the big rubbers to get the final small rubber into place, the whole lot suddenly shot out into the air. I cleaned all the grease off and started again with dry rubbers. It needed a lot of torque to compress the large rubbers sufficiently enough to get the small rubbers into place, even though I'd had them simmering in boiling water for a few minutes to soften them. I had to use a length of tube on the locking tool handle and ended up with a significant twist on the piece of gauge plate but the job was a good 'un, finally.

[Greybeard]

Mmmm. I had thought of using a smear of red rubber grease. Perhaps I'll change my mind. A similar experience fitting BSA fork slider circlips led to the purchase of several spares. I never did find the bugger that went into orbit
Thanks very much for the pics of the fitting tools. Theyre very helpful - the manual makes it sound so easy. I shall go and have a rake around to see if I have a spare clutch plate I can use.
I'll see what sort of job I have getting the new uns in the AJS before removing the G80's rubbers. Not that I'm windy of course

Steve

[Greybeard]

After seeing Pharisee's inspirational pics I sloped off into the workshop again to see what I could dig up. The only spare clutch plates I had were Ariel ones so were of no use. Whilst raking about at the back of the cupboard I came across a 1/2" thick slice of large diameter brass bar that I'd been given years ago and never found a use for. It just goes to show that hoarding useless 'junk' for that one day when it might come in handy does pay off eventually

I surfaced it off on the lathe and then milled a couple of flat sides which would enable it to be held in a vice. It was then a question of machining a central hole the same diameter as the inner spider's rear end to provide a secure locating 'bearing surface' for it. Three M8 holes drilled and tapped allowed the outer shell to be firmly bolted to the brass plate. I found that a length of Whitworth hexagon was a very nice snug fit inside the spider and so would allow a spanner to be used on it without fear of anything bending or slipping. I then got to thinking about the hexagon/spider tilting under pressure, so machined up a deeper bearing which I glued (using green Loctite) into the back of the brass plate along with a suitable 'peg' on the end of the hexagon.

cush drive tool 1.jpg

cush drive tool 2.jpg

cush drive tool 3.jpg

I have probably, as usual, wildly over-engineered a tool for a one off (or maybe 2 off) job, but at least it's kept me out of the way for the afternoon, for which the EPO (Enjoyment Prevention Officer) is extremely grateful

I'm now looking forward to the challenge of squashing rubber

Steve

[Pharisee]

Excellent job, Steve... If your new rubbers were anything like mine, you'll need a socket and and a long 'breaker' bar on that hexagon steel. The rubbers do soften a little in boiling water but don't burn your fingers!! An extra pair of hands would help. I had to lean on the tool with my body to keep the rubbers compressed while using both hands to fiddle the final rubber into place.

[ChrisTheChippy]

Looks like a great bit of fabrication . Expect to sweat and maybe blaspheme a bit . They really are b****ers to get in .
Regards Chris

[Greybeard]

Sounds like I should spend the rest of the evening brushing up on my profanities just in case I'll have a look through the TV channels, there may be some politicians being interviewed that I can practice on.

Steve

[dave16mct]

I think I'd have a go at removing those ridges before I go any further. You'd have a much smoother clutch action!
Dave.