The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: Gavin on 22.01. 2012 13:34

Title: Clutch rebuild
Post by: Gavin on 22.01. 2012 13:34
I am currently rebuilding a clutch and have removed all the indentations from wear on the basket where the outer dogs catch against it. while it looks a fine job, all true to centre and so on.. when I put the new (Bonded) plates in, not all 8 dogs contact the leading surfaces matching them. i imagine this is going to lead to a shorter clutch life. can you guys confirm that I need to file away the current contacting edges of the basket until all 8 are making contact?

Seems I'd rather look silly, than go silly and regret it later... Appreciate ya help. Thanks.
Title: Re: Clutch rebuild
Post by: orabanda on 22.01. 2012 14:15
It doesn't matter; don't panic.
You owe me a feed of crabs for that!
The Kalgoorlie Kid
Title: Re: Clutch rebuild
Post by: Gavin on 22.01. 2012 14:45
Oh man, these Orabanda oracles say nothing and expect food to be coming outa their ears !!!!

see ya Australia day mate.
Title: Re: Clutch rebuild
Post by: RichardL on 22.01. 2012 17:07
I, wisely, avoid debate with The Kalgoorlie Kid, having gotten so much good info from him that I would buy the face-to-face crab were I in his area of WA. I guess I'm safe on that, for now. I recently did some research that tells me that Perth is about as far away on earth as one can get from where I live, while still being on land. However, Kalgoorlie, not being Perth, puts Richard conveniently closeby to Chicago.

In any case, it seems that by the strictest concept, one could say that an unusual amount of force is applied by those tabs that do touch and, therefore, the basket is likely to get slightly more worn at those spots. While I also think it must not matter very much, if it were easy to get a perfect result one might try it. Unfortunately, it doesn't seem that easy. One would need to confirm that the leading edges of the tabs on the stamped plates were all perfectly 45 degrees apart. Then, the chainwheel would need to be adressed for the same quality.  So, after you've removed any bindy little ridges, like the man says,  best to go with "it doesn't matter."

Richard L.

Oops, edited. The inner tabs don't really matter with respect to the outers, but the same issue could be considered for the inners.
Title: Re: Clutch rebuild
Post by: muskrat on 23.01. 2012 08:03
 Yep throw'em in. BUT, as I do, any time you have the clutch apart from now on put them back in the grooves they came out off and in the same order.
 The one copping the most force will wear till it equals the second, and so on and so on till their all equal in load bearingness. Is that a word?.
It will all wear into each other in the long run.
 PS I mark each plate as it comes out with a dab of paint. Saves confusion after a few coldies.
Title: Re: Clutch rebuild
Post by: RichardL on 23.01. 2012 11:29
Title: Re: Clutch rebuild
Post by: BSA_54A10 on 24.01. 2012 13:09
An old speed way rider ripped my A 10 clutch off, Clamped all of the plates together then filed all of the tangs back to square.
He then filed all f the slots in the drum clan again, braised a small length of 1/16" key steel to each thrust plate then sized the tangs on the plates to fit the new slots.
He then center pinched one tang on every plate and either side of the slot that they fitted in.
Was the smoothist 6 spring clutch I have ever used.
HE also made a leaded bronze bush to replace the dreaded double row of balls.
This cured me for good from riding the clutch at traffic lights.
Hold it in for more than 3 seconds hen it overheated and locked solid.
Title: Re: Clutch rebuild
Post by: Gavin on 25.01. 2012 13:36
Thanks for the answers thus far: yep Trev I can see what your old Speedway mate was up to.... until you hit the bit about the double row of ball bearings. from that point on I am mystified.... which Orabanda will tell ya... ain't real difficult to achieve. Could you sharpen that bit up a bit please mate.... I have a 51 plunger frame... does that help in focussing the riddle? Can't recall a double row of ball bearings anywhere !!!!
Title: Re: Clutch rebuild
Post by: trevinoz on 26.01. 2012 06:19
                   No double row ball bearings in Plunger clutches, only rollers.

Title: Re: Clutch rebuild
Post by: BSA_54A10 on 26.01. 2012 12:45
that one slipped past the keeper.
My A 10 was a 56 swingarm with a 6 spring clutch and the PIA balls.