Stainless steel XBR downpipes

[SteveC#222]

I've just found these on Ebay - the guy has at least 10 pairs at £170 a pair  - Ebay 141376366318

[chris22]

Yup - I bought a pair. They are well made and fit well - Sandy Bike Spares are good to deal with.
Still looking for a pair of XBR exhaust flanges - surely somebody must have a rusty old pair kicking around that they can sell to me?

[SteveC#222]

Chris, I have a pair - check your PM's.

[timbo]

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.

[Oldtimer]

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.

Sounds a good price as Sandy is quoting twice that. It doesn't matter what you do, if you move away from the original set-up you will invariably have to alter something. As for the size of the pipes it all depends on the valve timing and valve size to clear the cylinder of burnt gases. The pipe is tuned to all the factors built into the engine to give the optimum performance but this is a variable thing one way to maxing the power and the other is for economy and quite running. The exhaust pipe is as much a part of the tuning process that invariably gets overlooked. A big open megga is not just for the looks and the sound, there is a reason for it !

[timbo]

Thanks for that advice  The downpipes from Sandy's look top quality, and are 35mm diameter, which is one of the reasons I asked the question on this thread. Do they come with clamps and collets included? The quote I have for £80 doesn't include any fittings, and is just for the bare bent pipe. In other words, I would have to cut the ends, and sleeve them down, then put ends on so that the clamps and collets can hold them on. Its all pie in the sky at the minute, as I'm really just looking into it 

[chris22]

When I spoke to Sandy Bikes last year they did not do the exhaust clamps but were intending to make them this year (as they had been asked for them on several occasions). Fortunately Steve got me out of trouble with a second hand pair. If you adapt 38 mm pipes they may not be able to take the collets which locate the pipes and clamps.

[timbo]

Sandy's list the clamps and collets on eBay, for near £40. They look total quality. I just wondered, if they came included with their pipes? I doubt it.

[welland99]

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.

Are you saying that the front down pipes consist of one pipe inside the other?  I've never heard of this before.  I wonder why it's like this? 

I have an after market Micron system with 2 into 1 and one of the down pipes is getting quite corroded.  I was worried that I'd have to source a new down pipe when it finally corrodes through.  But, if it is less corroded on the inner pipe than the outer, then I can turn the worry down a notch....

[timbo]

Hi, if you have a Micron two into one, then your downpipes are skinny singled skin jobbies. The two into two originals were double skinned, so the outer would stay nice and shiney chrome and not blue with heat. Also, they are supposed to look more aesthetically pleasing on the eye   

[Dick Scratcher]

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.

Are you saying that the front down pipes consist of one pipe inside the other?  I've never heard of this before.  I wonder why it's like this? 

I have an after market Micron system with 2 into 1 and one of the down pipes is getting quite corroded.  I was worried that I'd have to source a new down pipe when it finally corrodes through.  But, if it is less corroded on the inner pipe than the outer, then I can turn the worry down a notch....

Double-skinned exhaust pipes are very common on Jap O/E systems.

[Oldtimer]

Sandy's list the clamps and collets on eBay, for near £40. They look total quality. I just wondered, if they came included with their pipes? I doubt it.

Clamps will be on the pipes if they are 2 into 1. Still require copper gasket though.

[Propellor]

As has been said, the japs were using double skinned pipes ages ago. I was told (circa 1976) that the reason was to stop the pipe discolouring (as Timbo mentioned).

I'm sure that was the main reason but I wonder if there was a secondary reason. The inner pipe would run quite a bit hotter than it would if directly open to ambient air, with associated ambient air movement. So the inner pipe is insulated, to a point.

[Moto63]

Very interesting point, and let's face it, it looks a damn sight better than PIPE WRAP.

[Oldtimer]

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.