The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: Rocket Racer on 21.10. 2009 08:04

Title: starting from scratch - what clutch?
Post by: Rocket Racer on 21.10. 2009 08:04
My collection of parts based around a '55 road rocket motor currently has no clutch. I would like to run a single row chain driven clutch and retain a crankshaft cush drive. I would be interested to know 1. what clutches are recommended and 2. supplied by whom? This will be going into a racing sidecar application but I was intending to run a wet primary.

Wotcha reckon lads and lasses? ????
Title: Re: starting from scratch - what clutch?
Post by: fido on 21.10. 2009 09:10
The Triumph type four spring clutch as used on the last of the A10s would be the one to use. The adapter to fit the BSA gearbox shaft is readily available.
Title: Re: starting from scratch - what clutch?
Post by: LJ. on 21.10. 2009 09:26
Yes I'll second the four spring clutch... Just changed it from the six spring and really did make all the difference. I would think the four spring would be good enough for racing and sidecar lugging as well although there are good modern clutches available but out of my scope.
Title: Re: starting from scratch - what clutch?
Post by: Brian on 21.10. 2009 10:44
I seem to recall someone on the forum put a A65 clutch into a A10 and it all fitted ok. Might be easier to find one of them (and cheaper).

Hopefully whoever it was may read this thread and chime in.
Title: Re: starting from scratch - what clutch?
Post by: tombeau on 21.10. 2009 11:11
I've got an A65 on mine.
It was a very straightforward fit.
As I recall (I did it an awful long time ago) there is a standard adaptor for the clutch to fit. You need to do something about the big spring and lobes on the crank. 
Gives you triplex primary. Looking at the photo...shouldn't I have a smooth plate on the outermost side? oops.
Doesn't seem to slip.
I think Flashblack has one on his too.
Cheers,
Iain
Title: Re: starting from scratch - what clutch?
Post by: fido on 21.10. 2009 11:33
With the A65 sort you lose the crank cush drive. Is there a cush drive incorporated in the clutch?
Title: Re: starting from scratch - what clutch?
Post by: muskrat on 21.10. 2009 11:41
G'day Fido, the 4 spring will take a beating. Mine lasted 4 years on the track and is still in great shape. Just retired it to the spares cupboard in favour of a belt setup.
Cheers
Title: Re: starting from scratch - what clutch?
Post by: tombeau on 21.10. 2009 12:14
Fido,
Yes there is a cush drive in the clutch.
Cheers,
Iain
Title: Re: starting from scratch - what clutch?
Post by: chaterlea25 on 21.10. 2009 18:13
Hi Rocket
For the ultimate clutch in my opinion (IKBA)
see the Suzuki conversion on one of the threads here

http://www.a7a10.net/forum/index.php/topic,1463.100.html

I know Phil Pearson does these in the UK but they are expensive!
I am going to add a Suzuki GSXR clutch basket to an existing BSA chainwheel or buy a blank sprocket and work from there  *idea* *idea*
I got the Suzuki clutch on Ebay cheap I think at £50
Cheers
John
Title: Re: starting from scratch - what clutch?
Post by: flashblack on 21.10. 2009 20:04
Hi RR

 Tombeau is right, i do have the same set up as him, all i had to do was align the chain,by making the appropriate distance piece for the end of the crank, other than that it was all straight forward.
Richie