Author Topic: 4 Spring Clutch, my worst subject !!!  (Read 227 times)

Offline A10 JWO

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4 Spring Clutch, my worst subject !!!
« on: 04.05. 2019 16:07 »
Took the primary chain case off as the clutch had stuck fast on my new 500 acquisition ( the bike had been stored for several months ). Found a complete brand new four spring clutch with an alloy cover plate similar to the SRM one in my 650. The chain case was full of automatic gearbox fluid.  I stripped the clutch and  gunked all the plates and washed them in hot soapy water to remove the said oil. This clutch has probably done 600 miles. No sign of wear or damage anywhere. All re-assembled and do you think I can get the clutch to engage evenly, it looks like a dustbin lid rolling down the road. I will state that I have put this together totally dry at this stage. Should I have bathed it all in fresh SAE 20 before I installed it or am I missing something, def' my worst subject.
Thanks.

Online Billybream

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #1 on: 04.05. 2019 17:04 »
Try petrol to remove the oil on the friction plates, and yes assemble dry.
Check both friction and plain plates are totally flat and the splines are burr free.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline A10 JWO

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #2 on: 04.05. 2019 17:33 »
Thanks Billy, will pull it down again and have a look, it has 6 metal plates and 5 corked, don't know what make it is but going by the rest of the bikes it won't be a cheap one. The adjustment nut is at it's limit as if the push rod is a bit short, it may be the thickness of the billet cover.

Just found this in another posting from last July, talks about friction plate goes in first, not metal, see below which I cut and pasted.

had my clutch apart last couple of days, my SRM plate is not machined as pictures here also has Devimead cast in it, on re-assemble I consulted SRM site (just don't trust my memory these days, guess some of you are similar) and lo and behold I had a plate to many, I had a steel plate first, SRM say friction plate first, so put it together that way, seems fine , one spring turn showing, one finger operation.

Online Billybream

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #3 on: 04.05. 2019 19:11 »
Another trick is to cut the push rod in half and insert a suitable sized ball bearing which will give you more adjustment.
Devimead were the original BSA tuning experts and  I think SRM took over there business.
It is best to try and set the clutch pressure plate up running true to within a few thousands of an inch, people tend to use a dial indicator rigged upremotely, this effort is well worthwhile.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Offline worntorn

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #4 on: 04.05. 2019 20:18 »
Are you certain these are cork friction plates and not some modern material like Kevlar?
Barnett makes Kevlar plates for some old Brit bikes.
I installed a set in my Commando, it's a beautifully smooth operating clutch now. The preferred primary oil for the Kevlar plates is ATF type F.


Offline ironhead

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #5 on: 05.05. 2019 11:31 »
Hi JWO.
If it has the standard A10 4 spring clutch center ( with the lip) a steel plate goes in first.
If the center has no lip like the unit trihards & later A65's , a friction plate goes in first & sits up against the sprocket, then all the thrust from the spring pressure against the plates pushes up against the sprocket.
This is why a thrust washer is fitted between the bearing hub & sprocket on later bikes. If you don't have a modified hub doing things this way will cause the sprocket to grind away on the bearing hub. ( hope this makes sense)
Cheers Steve.
SA

Offline A10 JWO

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Re: 4 Spring Clutch, my worst subject !!!
« Reply #6 on: 05.05. 2019 16:02 »
Thanks for replies, transpires I had two different size springs fitted which I did't bother to check, I just chucked them in the parts washer. Lesson learn't.