AMC clutch query

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AMC clutch query

Postby MalcW » Thu Jan 02, 2020 9:49 am

Hi

Happy New Year to you all.

A friend of mine has recently bought a 1960 650 twin,alternator model. It started and ran fine, with good compression, but had 2 problems. Firstly, it was pumping oil into the chaincase, gradually filling it. The gauze/felt filter at the front of the engine was filthy, and I've got him to wash it out in petrol, and dry it thoroughly. The ball bearing is moving freely on its spring.Could this be the problem, or should we look elsewhere?

Secondly, the clutch had rotational play on the gearbox shaft. Initially I thought it might be destroyed shock absorber rubbers, but on removing the clutch retaining nut, the clutch cane straight off with no need of the puller. It seems very slack on the splines; the gearbox shaft looks fine, but there is evidence of wear in the clutch. I've never taken one apart before, other than clutch plates: do you think a new centre web should fix it, renewing the rubbers at the same time?

The owner of the bike is new to British classics, and I've told him he needs to join this club, which he will. But I'm trying to give him a head start in getting it fixed ready for the Spring.

Thanks,

Malcolm

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Re: AMC clutch query

Postby Mick D » Thu Jan 02, 2020 10:43 am

Hi

A blocked crank case filter could be the cause of the chain case filling with oil and now your pal has cleaned it out and is assured the check valve is functioning I'd suggest running the bike to see if the over oiling has been cured - if it hasn't I'd suggest you look at the breather.

The clutch centre should have very little rotational play on the main shaft when the retaining nut has been loosened - was the retaining nut loose when you observed the play?

A new centre will improve the situation but you may also need to examine the main shaft for both radial and axial damage to the splines, (axial wear at the inboard ends of the splines affects the clamp up of the centre to the main shaft).

Have Fun Mick

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Re: AMC clutch query

Postby MalcW » Thu Jan 02, 2020 11:14 am

Mick D wrote:Hi

The clutch centre should have very little rotational play on the main shaft when the retaining nut has been loosened - was the retaining nut loose when you observed the play?


Hi Mick

Someone on the past had changed the nut from the correct undersized one to something else, so he had a job finding a box spanner to fit. As a result, I don't know how tight the nut was - when I looked at it before he managed to remove it there was appreciable play and no obvious in/out play.

Cheers, and Happy New Year,

Malc

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Re: AMC clutch query

Postby Mick D » Thu Jan 02, 2020 11:24 am

Hi Malc

Fingers crossed then - he might be lucky and get away with just a new centre shock absorber, rubbers, retaining nut and lock washer.

Regards Mick

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Re: AMC clutch query

Postby 56G80S » Sat Jan 04, 2020 9:12 pm

Memory may be failing me but I thought the spark plug spanner (I use a box spanner) fits the clutch centre nut? Sure I had to do this when it came undone many years ago. Yes, I know it should be a Burman but the AMC my preference.

Johnny B

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Re: AMC clutch query

Postby MalcW » Mon Jan 06, 2020 9:37 am

56G80S wrote:Memory may be failing me but I thought the spark plug spanner (I use a box spanner) fits the clutch centre nut? Sure I had to do this when it came undone many years ago. Yes, I know it should be a Burman but the AMC my preference.

Johnny B


Yes, I believe that's correct if the clutch has the original undersized nut. This one has been changed at some point in the past.

Malc

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