The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: chrisannesam on 06.11. 2011 21:35

Title: Inner PCC to crankcase washer
Post by: chrisannesam on 06.11. 2011 21:35
Hi, I have a problem getting my 1956 A7 SS clutch sleeve to mate on the tapered gearbox spline without fouling the sliding plate.  The parts book suggests that there is only a joint washer at the front. However, the Haynes manual suggests a metal plate and a paper gasket.  Which is correct?  I have the inner bolted up around the crank and the correct rear spacer added.  With just a paper thick gasket I think this fouling would go away...
Thanks in advance,  Chris
Title: Re: Inner PCC to crankcase washer
Post by: A10Boy on 07.11. 2011 09:27
Hi
I'm not sure on the A7, but I would follow the parts book rather than the Haynes in most cases. You need to make sure the inner isnt distorted as it's tightened up, I have seen them with cracks caused by the wrong allignment, although thats usually caused by a missing lower frame bolt spacer which you have.
Title: Re: Inner PCC to crankcase washer
Post by: BSA_54A10 on 07.11. 2011 09:52
Were the part fitted together properly before or have you replaced some thing.
Despite what the parts books say there are a lot of different clutch centers and they have different sized holes so they can fit at different positions on the main shaft
Title: Re: Inner PCC to crankcase washer
Post by: chrisannesam on 07.11. 2011 10:36
The old clutch centre was obviously wearing for quite some time as it knackered. As is the plate.  Looking at the parts numbers it appears I have the inner and outer of a later 4 spring clutch model.  These came with a metal spacer and 2 paper gaskets at the front.  The 6 spring model, mine, did not have a metal spacer just a paper gasket.  So hopefully, that's me problem solved.  Thanks for the help thus far.  Cheers,  Chris
Title: Re: Inner PCC to crankcase washer
Post by: trevinoz on 07.11. 2011 20:00
They all should have the front spacer disc.
 Trev.
Title: Re: Inner PCC to crankcase washer
Post by: chaterlea25 on 07.11. 2011 22:24
Hi Chris,
Search on the forum threads *idea*
There have been a few on this subject
The problems come from different clutch adaptors and also there are different crankshaft sleeves
As Trev says they all have a plate, different bikes require different or no spacers at the bottom rear
this is the last one to make a spacer for after all else is sorted

Cheers
John O R
Title: Re: Inner PCC to crankcase washer
Post by: RichardL on 07.11. 2011 23:53
Trev.

Am correct in adding that the frnot spacer is needed to assure adequate clearance between the cush nut and the inside of the outer cover?

Richard L.
Title: Re: Inner PCC to crankcase washer
Post by: bsa-bill on 08.11. 2011 09:32
Quote
different bikes require different or no spacers at the bottom rear
this is the last one to make a spacer for after all else is sorted

Do I recall correctly that in one of the threads on this subject, the case was on the wrong side of the frame?
Title: Re: Inner PCC to crankcase washer
Post by: trevinoz on 08.11. 2011 19:28
Richard L,
                    Your theory is as good as any, I have never considered the reason for the spacer.
If a clutch centre from a single is used, it will definitely foul the sliding plate.
The single centre can be identified by the square shoulder adjacent to the scroll sleeve whereas the twin type is cut away to clear the bush in the plate.

   Trev.
Title: Re: Inner PCC to crankcase washer
Post by: RichardL on 08.11. 2011 20:12
Yeah, I got to thinking that the mold maker made a bunch of master molds for the outer cover that were all alike and just a bit off. Then, needing a quick solution, the idea of the spacing washer was born. Once it worked, why bother replacing the molds?

Richard L.
Title: Re: Inner PCC to crankcase washer
Post by: chrisannesam on 18.11. 2011 08:41
Update.  The new clutch centre is fitted and the clutch is now miles away from the chaincase back plate.  Problem now is that the sprockets are not in alignment.  Bizarrely, although the clutch has moved out to clear the back plate, the teeth are now inside the front sprocket by 5.1mm.  I have had the crank spacer machined to suit and now it all fits.  And no front metal spacer as per parts book and photo of A7 SS in a museum in the Midlands!