Author Topic: Cracked mainshaft  (Read 711 times)

Offline coater87

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Cracked mainshaft
« 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.
Central Wisconsin in the U.S.

Online muskrat

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Re: Cracked mainshaft
« Reply #1 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
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, .
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Offline Topdad

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Re: Cracked mainshaft
« Reply #2 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*
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Offline coater87

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Re: Cracked mainshaft
« Reply #3 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
Central Wisconsin in the U.S.

Offline coater87

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Re: Cracked mainshaft
« Reply #4 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
Central Wisconsin in the U.S.

Online chaterlea25

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Re: Cracked mainshaft
« Reply #5 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
1961 Super Rocket
1963 RGS (ongoing)

Offline coater87

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Re: Cracked mainshaft
« Reply #6 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*
Central Wisconsin in the U.S.

Online chaterlea25

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Re: Cracked mainshaft
« Reply #7 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

1961 Super Rocket
1963 RGS (ongoing)

Offline Topdad

  • bob hebdon
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Re: Cracked mainshaft
« Reply #8 on: 31.05. 2016 11:06 »
I bought one from Draganfly ,about 3 yrs ago,  they may be worth an e-mail, Bob.
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Offline morris

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Re: Cracked mainshaft
« Reply #9 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.
'58 BSA A 10 SA
'52 BSA A 10 Plunger
'55 MORRIS ISIS
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