The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 1946-1950 => Topic started by: SixFingerJack on 30.01. 2020 15:56
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Hi folks,
Do any of you learned people know if the exhaust port spacing/angle/diameter on the long stroke engine is the same as the later models?
The reason I'm asking is, that nobody seems to list a 2 into 1 exhaust to fit the long stroke, only the later A7 and A10s, and I would like a 2 into 1 for my '48 rigid.
Cheers.
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Probably the same. I think that the exhaust pipes for the long stroke are the same as the short stroke.
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Cheers Trev
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Jack, Indeed they are. The 1947 parts catalogue lists 67-2675 (o/s) and 67-2679 (n/s) exhaust pipes for the A7 and Star Twin Longstroke rigid frames. The same parts continue to 1949, Longstroke rigid and plunger frames, and are the same pipes used on the A7 Shortstroke, rigid and plunger.
So a 2 into 1 system from a post 1950 model should do. Experience shows they rarely fit from the box, and if possible it is better to get one which is unplated, then cut and shut to fit. The alternative is a used set, as at some stage some other fella had the hassle making it fit, but many are abused as getting the pipes to come apart usually requires a bit of violence.
Swarfy
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Thanks for that Swarfy.
I reckon a second hand set would be a good idea, as I'm gonna be chopping the silencer end about a bit too.
Do you think there's any point in putting a wanted ad up?
I suppose there's nowt to lose, and also, I just answered my own question...…
The other option is to get a stainless 2 into 1, an re-polish it after it's been welded, but that may be a bit expensive?