BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: DAVE BRADY on 07 May, 2020, 20:54

Title: Early A65 4 spring clutch
Post by: DAVE BRADY on 07 May, 2020, 20:54
How many of you are running the early 4 spring clutch in your A65/A50?

Compared to the later 4 spring and 3 spring it is a work of art.  The centre is sandwiched between 2 trust washers/spacers with the whole thing held together by a plate on the back fastened in place with 6 small screws.  Compared to the others there is no slack or wobble in this clutch.  Why did BSA think that it needed 'up grading'?  The others work great once the spring pressure pushes everything together but pull in that lever and things start to move about especially if there is a bit of wear.  Even a belt drive kit I have is sloppy and this is supposed to be an upgrade.
I recon it was cost.  Machining the centre of the clutch basket must have been 3, 4 or more actions, making and machining the back plate a few more actions.  So a bit complicated and complication = cost.
So do away with the well made clutch and make another 4 spring clutch with a lot less machining that wobbles about.  A bit lighter perhaps but simpler to make.  Simpler = cheaper.
What to do next?  How about an upgrade to a 3 spring clutch?  Only 3 springs, 3 spring cups, 3 spring retaining bolts and nuts, only 3 holes to make in the centre, only 3 vanes in the cush drive.  Yes! Definitely better, simpler, less parts = cheaper.
BSA would never have stopped using a superior component to save money would they?

Dave.

Title: Re: Early A65 4 spring clutch
Post by: Mike Farmer on 08 May, 2020, 16:47
 :) :) :)

I've got an early 4 spring as described by your good self and guess what-----it wobbles. I was seriously worried about it until I mentioned it here a few weeks back and was assured that "they all do".

Take care and happy and safe riding

Mike 8) 8) 8)
Title: Re: Early A65 4 spring clutch
Post by: DAVE BRADY on 08 May, 2020, 18:10
Hi Mike,

Yes a bit of wobble is inevitable with the bearing arrangement but a lot less than the later ones.  Have you stripped yours to see if the trust washer need replacing?  It looks like they are hard to get but could be made if needed.  I managed to find a brand new basket and fitted new rollers and some better thrust washers.   With the centre fitted and a bolt through to hold it all together there is no detectable wobble although I expect a bit when in use.  Similar set up with a belt drive centre etc. bolted together lots of wobble.
The test will be when it is put to use.

Dave.
Title: Re: Early A65 4 spring clutch
Post by: Mike Farmer on 08 May, 2020, 20:00
 :) :) :) :)

Mines just been rebuilt new washer etc. We'll see??

Mike 8) 8) 8)