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Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 11:16 am
by REW
At a club meeting last night I was asked: "are all exhaust pipes for twins the same (bend)?"

I have no idea but would have thought not but said I would ask for guidance. The bike in question is a 1959 650 roadster that the guy has ridden since he was a teenager. He bought and stored a smart pair of chrome exhaust pipes decades ago and on trying to fit them at the weekend discovered that once in the heads the pipes splay out at the bottom rather than lie parallel to the frame rails.

So, how do pipes differ over the years and models?

Re: Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 11:30 am
by G15 Roy
the 1959 heads on the 650 were a one off and also was the bends in the exhaust pipes and hard to find new ones that fit.

Re: Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 2:52 pm
by Rob Harknett
I guess engine height may cause pipes to differ. Perhaps that's why late 30's 250 350 & 500 all have different pt. no's. Although in post war era the difference in 350 & 500 may pipe dia. Same may apply to some twins which I know little about.???

Re: Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 3:43 pm
by dave16mct
1960-on twins have a different exhaust port angle. 500cc twins were 1 1/2", 650cc were 1 5/8". So lots of variations.
Dave.

Re: Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 7:57 pm
by REW
Thanks everyone - I suspect a nice chrome set of pipes will be on sale soon...

Re: Twin exhaust pipe compatibility

Posted: Thu Nov 08, 2018 10:57 pm
by Rob Harknett
REW wrote:Thanks everyone - I suspect a nice chrome set of pipes will be on sale soon...
Quite a few AJS & Matchless here, off the peg. Four or five pages. https://www.feked.com/exhausts/ajs-matchless/page-2/