Stainless steel XBR downpipes

[Propellor]

I once worked in exhaust development for all the big car manufacturers and the reason a double skin pipe was called for is to quieten the exhaust from 'ringing' ie quietening it down.

Interesting one that OT.

[iansoady]

I might be getting a few pairs of downpipes made locally. What I want to know is, how much does the diameter of the pipes affect the running. Do you have to re jet?
As you all know xbr pipes are double skinned, the inner pipe is quite small, as with the aftermarket 2 into 1s. If I get pipes made to the outer size, as in 38mm, will it affect the running? As 38mm is the min size the local stainless exhaust guys use. I've been quoted £80 for a pair.

Hi there,

Just wondered who your local chap was as I'm considering stainless pipes for the 1931 Sunbeam. They're a small 40mm (1 9/16" in old money). But I'd need flanges so don't know if that's possible.

[timbo]

Hi ian, it was a place that makes stainless exhaust systems for cars, but I never pursued it any further, so cant really help you out 

[manxie]

When I had my XBR, I wanted to take the 2 into 1 of it and revert back to a 2 into 2. I had some lovely stainless front pipes made by Roy at Ospipes, http://www.osmc.co.uk/index.htm perfect fit and great service, I would certainly buy from him again 

[iansoady]

Yes, I'd picked them up from another thread here. I tried to ring last week but no answer - maybe summer hols. I'll try again this week.

[Dick Scratcher]

I've got a pair of stainless Motad pipes for my Honda CB250RS and I've 'gone back' to chrome ones as the SS ones get to look very discoloured and shabby in no time at all.