The BSA A7-A10 Forum

Technical => Clutch, Primary, Gearbox => Topic started by: andy2565 on 20.05. 2010 09:16

Title: mainshaft change
Post by: andy2565 on 20.05. 2010 09:16
this maybe common nowledge but i only heard recently,that if change the gearbox mainshaft on the later bsa gearbox and put the plunger mainshaft in instaed,this means you can use a norton clutch or an early jawa NEB speedway clutch,got to be better than the bsa clutch. 
Title: Re: mainshaft change
Post by: Brian on 20.05. 2010 10:53
I dont know about the shaft change but when you say that its got to be better than the BSA clutch what clutch do you mean. The six spring as fitted to the early swingarm A10's wasnt the best design but the four spring fitted to the later A10's is a very good clutch and works perfectly well. If you have the earlier six spring then simply change it for a four spring, a lot easier and cheaper than changing gearbox shafts.
Title: Re: mainshaft change
Post by: muskrat on 20.05. 2010 12:00
G'day Andy,
                    I agree with Brian. The 4 spring jobs are much better. The shafts will interchange but don't know if other breeds of clutch will fit.
 You could also go the whole hog and fit a belt primary with a sNorton diaphram clutch, I did and love it. But $$$
Cheers
Title: Re: mainshaft change
Post by: beezalex on 20.05. 2010 15:48
Now that sounds interesting...I'll have to find a norton clutch center then and see.
Title: Re: mainshaft change
Post by: andy2565 on 20.05. 2010 16:13
havn't done it yet, but my sport being grasstrack racing and classic scrambling,i have a few norton clutch's laying around,any canibalising of gearbox's is a no-no,but if you have the parts ,give it a go,i have only experianced the early bsa clutch's,when i had a 53 star twin,it was always a bit stiff,and i see autocycle have made some belt drive kits for just under £500,i have bought an a10 to restore,but have not finished a goldstar restoration yet as i cant find a dbd34 engine.