xj900f (seca) downpipes/headers diameter?

hi, i have just got another xj900f with a 4 into 2 exhaust and the downpipes/headers on it are 41.5mm in diameter and look awesome. I think this may be original but there is nothing written on the silencers. The others i have are fitted with motad 4into1 with a downpipe/header diameter of 32mm and look pathetic by comparison. I have looked at a lazer/jama 4 into 2 but they have a diameter of 35mm. What i need to know is can i source the 41.5mm pipes as an off the shelf item in stainless steel or will i need to have them fabricated or make them myself. I am in the uk, but if they are avaliable in the us and shipping is reasonable ....

 

Look closely at the head pipes themselves where they join the collector box, or whatever part of the exhaust system they join. Original Yamaha pipes will have the part numbers stamped into the pipes close to the end.

The original pipes are generally larger in diameter than aftermarket pipes because the originals were double-walled and virtually all aftermarket pipes are single-walled pipe.

They probably won't be available "over the counter" anywhere; you'll need to embark on an eBay search; and they'll only be chrome.

Good luck. I've assembled two complete stock 550 systems from eBay and salvage; the 900 will probably be even more of a pain.

 

Drop a line to Mark at "mcperformance@bigpond.com" he will probably be able to advise you....

 

thanx for the answers. Have taken the exhaust off and it is double skin. So looks like i may be getting a better fabricator than me to build me a stainless one.

 

No real need other than cosmetic for the double-walled pipes.

The double-walled construction keeps the man on the street from seeing "blued" pipes; it's just a "perception of quality" thing.

Back in the day, the British bikes and the BMWs, Guzzis, etc., all had single-walled pipes, which will discolor, it's normal. The Japs came along with double-walled pipes because it gave the appearance of higher quality, since the outer pipes don't turn blue.

Purely cosmetic.

 

yes totaly cosmetic. Have got a motad with stainless steel downpipes on it now, but i like the look of the bigger diameter pipes and the twin silencers but don't want the rusting with chrome pipes. I also don't think much of the build quality of the motad. I am doing it purely because i like how it looks not because i think it is necessary. Thanx for your replies guys.

 

hi chaps i'm new to this forum as of a hour ago ! i have been fabricating a collector box & repairing the header pipes on the 900f ive acquired, it seams all the uk bikes rotted out !

 

All that salt air, like here on the west coast of Canada.
Nice fabrication

 

thanks ! it's just a rough job to get the bike up and running, i don't have time to go crazy and make a stainless collector, plus all the engine is badly corroded (with all the salt as you say) i don't want to spoil that look - it tells a story if you know what i meen

 

Ziggy nice work how I wish I could do that with my XJ 900f exhaust.

 

it's been a labour of love i can tell you my mate !! a genuine right pain in the neck ! had to weld together under the bike laid on my back ! it's not pretty but it's solid..
i'm riding to italy on the bike in july !

 

mig with gas FTW. Great work!