The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: coater87 on 25.05. 2016 23:42

Title: Cracked mainshaft
Post by: coater87 on 25.05. 2016 23:42
 I was lapping the taper on the mainshaft and noticed a crack. I never would have noticed it without the lapping paste highlighting the hairline split.

 Is this common or is this another case of the bike showing hard use?

 I have contacted autocycle but still have not gotten word back from them. I sure hope they have a mainshaft for a STD box.
Title: Re: Cracked mainshaft
Post by: muskrat on 26.05. 2016 11:06
Bugga, any crack is bad but how bad/where is it?
I've given my cafe's std box a real hard life racing for 8 years, very rarely using the clutch. It's as good as when she left the factory.
Cheers
Title: Re: Cracked mainshaft
Post by: Topdad on 26.05. 2016 13:54
Shame you're so far away. I've been rummaging through my gearbox spares for another member and have a spare ,just to expensive to post I would think ,Bob  *conf*
Title: Re: Cracked mainshaft
Post by: coater87 on 27.05. 2016 01:08
 Musky, without a crack check its hard to be certain, but it looks like the crack goes through the threads, through the taper and stops about an inch later. The only thing I can think of would be if someone put a tapered punch into the pushrod hole and smacked it a good one.

 Bob, I really appreciate that thought! If I don't have a decent spare somewhere, I will just source a new one. You right on the shipping cost, it would probably be 1/5 of a new shaft.

Lee
Title: Re: Cracked mainshaft
Post by: coater87 on 27.05. 2016 23:31
 Heard back from Autocycle, they sold out at something called Stafford. The e-mail says a Goldstar shaft can be used with simple mods if I am stuck, or I can wait a while until they make some more (could be a while, they are behind).

 I found a shaft in the shed, as long as its not too bad or cracked (have not looked closely at it) that is what I will go with that. I have a second box now thats in pieces, and one day maybe I will build it into a spare.

 If my spare shaft is junk too, I will post what I have to do to get a Goldstar shaft to work.

 Lee
Title: Re: Cracked mainshaft
Post by: chaterlea25 on 29.05. 2016 18:15
HI,
De Groot BSA in holland have new mainshafts listed
http://www.degroot-bsa.nl/index.php?route=product/product&path=51_60&product_id=2558

Its a pity you didnt find the cracked shaft before doing all th work on the Suzuki clutch
A splined mainshaft from a plunger box will interchange, and the suzuki 550 centre only needs a little modifying to fit it

John
Title: Re: Cracked mainshaft
Post by: coater87 on 30.05. 2016 02:48

Its a pity you didnt find the cracked shaft before doing all th work on the Suzuki clutch
A splined mainshaft from a plunger box will interchange, and the suzuki 550 centre only needs a little modifying to fit it

John

 Thanks for the link John, do you have any idea if this shaft is made by some company called MCA? I have no idea who they are, but I have not heard much good about them. I believe autocycle makes their own, and I like doing business with the guys who actually made the part.

 As far as the clutch, I would not change the path I took even if I could go back in time. I think the clutch I built will work fine, and it was a lot of fun to make it. Building that was the most fun I have had with this bike since I got to go through all the boxes it came in. *smile*
Title: Re: Cracked mainshaft
Post by: chaterlea25 on 31.05. 2016 00:05
Hi,
I have no idea where De Groot source the shafts??
I have bought lots of parts from autocycle, Good quality and lots of NOS bits

John

Title: Re: Cracked mainshaft
Post by: Topdad on 31.05. 2016 11:06
I bought one from Draganfly ,about 3 yrs ago,  they may be worth an e-mail, Bob.
Title: Re: Cracked mainshaft
Post by: morris on 31.05. 2016 21:26
HI,
De Groot BSA in holland have new mainshafts listed
http://www.degroot-bsa.nl/index.php?route=product/product&path=51_60&product_id=2558

Got one of them in the SA's box. It's by far the best quality BSA part I ever bought.