Exhausts

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foxer1

Junior member
Location
Herts'/Cambs
Hello everyone I'm quite new to this site and in the process of buying a barn find 81 jota . The exhausts are shot for sure but have found sond front a 76 will they fit ?

Thanks in advance Andy
 
All stock 180° and Jota 120 factory exhaust systems will interchange. If they actually work satisfactorily with your engine spec is another topic.

piet
 
Talk to Malcolm Cox, he will sort you out the nearest to original but genuine ones? They are just empty cans with a tuned pipe at the end.
Tim Healey made the original batch, after that who knows? Malcolm's are steel, others are stainless but they all do the same job. All of them are pattern now, nobody cares.
 
The collector Keihan produces is crap if they still produce them as mine was done. It kills midrange and top end power due to a totally wrong design. Mine started glowing cherry red on the dyno... It also has a tendency to brake... see:

Yet another collector box thread...

Hi all, No wonder the Sprint was noisy coming back from the Island... 'Twas a bugger getting the short broken ends out of the silencers... Now, I know all about having the system mounted properly and nothing under tension, and I admit that earlier collector box failures could be down to...
laverdaforum.com laverdaforum.com
 
Laverdalothar said:
The collector Keihan produces is crap if they still produce them as mine was done. It kills midrange and top end power due to a totally wrong design. Mine started glowing cherry red on the dyno... It also has a tendency to brake... see:

Yet another collector box thread...

Hi all, No wonder the Sprint was noisy coming back from the Island... 'Twas a bugger getting the short broken ends out of the silencers... Now, I know all about having the system mounted properly and nothing under tension, and I admit that earlier collector box failures could be down to...
laverdaforum.com laverdaforum.com
Click to expand...
Interesting read, and especially the reply from Dellortoman. "What stainless steel doesn't like is any kind of cyclic load because it work hardens and cracks. The headers and collector are all solidly mounted to the bike via the exhaust port clamps. But the muffler cans are free to move a little bit because of their rubber mounts. So they bounce around on the ends of the collector box spigots, imparting cyclic loads to both the collector box and muffler spigots. If you have a stainless system, you might be better off ditching the rubber mounts and making up solid equivalents."

I have had a Keihin system on my Guzzi T3 for many years (and it's been across to the Isle of Man numerous times) without any problems with stress fractures, and that's a solid mounted system. Dellortoman has a valid point. As for the issue with performance. I've never had anything glowing, but my Guzzi is still performing perfectly well through the rev range.
 
The Keihan collector will eventually work harden and crack from the pressure changes in the pipes not from the mounting method. Stainless was not a good choice for the part.

I have BMW K1200RS with a Remus stainless steel exhaust system made in Germany and it was not cheap! It also work hardened and cracked on a bike that does not vibrate at all.
 
Exhausts in stainless steel are not a problem in itself - every new car or bike you buy these days will have it. With Austenitic and ferritic grades used where appropriate. The key is the detail design. Thermally-induced strain being the most frequent failure mode. The problem with our old clunkers is that the stainless steel versions are often near-copies of the originals, where mild steel would do the job, but not in stainless.
 
1200ts said:
The Keihan collector will eventually work harden and crack from the pressure changes in the pipes not from the mounting method. Stainless was not a good choice for the part.

I have BMW K1200RS with a Remus stainless steel exhaust system made in Germany and it was not cheap! It also work hardened and cracked on a bike that does not vibrate at all.
Click to expand...
Has nothing to do with Stainless, it has to do with a crappy design. To much pressure and heat are building up in the collector due to it's design and that causes the system to burst. Vibrations might not help on holding it together longer, but it's definitely a massive design fault. As said, the thing was glowing orange red on the dyno after just a few seconds...

After a local exhaust specialist looked at it for a second, he smiled and said: you should not build a collector like that, this is just wrong.

He built the 3-2 "collector" I have now and that one works fantastic. It is made by cutting the middle piece of the Keihin out (which is crap) and use the front 3 pipes, the rear 2 connectors to the mufflers and 2 extra pipes with slightly thicker diameter. No resistance, no back-pressure, no cracking, no orange red glowing. Just works.
 
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