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Posted: Wed May 23, 2007 1:08 pm
by Demomike
Agree the fewer the weld seams the better, but forming is much easier in two halves...Glad to hear they're close though :D

Posted: Tue Jun 19, 2007 11:57 am
by tweeder
well CRAP! THAT was an exercise in futility. the homebrew chamber didn't do one freaking bit of good..... somethin' else must be fubar'd.....



burnin' the midnight oil to make it to Montana.....well, at least dad's burnin' the midnight oil -- i can't take them freakin mosquitos :roll:

Re: Can a Expansion Chamber be built for....

Posted: Sun Jan 25, 2009 9:06 pm
by SuzukiTom
I know that this thread has been dead for a few months now, and ended on a sour note. But I think that it deserves revisiting.

The exhaust system on the LJ I just bought is in poor condition. Although the expansion chamber seems ok, the rest of the system is very rusty. I happen to have some experience with tuning high-performance 2-stroke exhaust systems ('70's Kawasaki H1/H2 and Suzuki GT series motorcycles). I was going to make my own system, but I no longer have access to an engine dyno that I would use to test various configurations. But fortunately, I don't have to. There was a photo of a professionally designed system posted to this forum earlier in this thread. The photo's a bit small, but it clearly shows the entire system from the header pipe to the exhaust outlet.
LJ20Chamber2.gif
LJ20Chamber2.gif (34.79 KiB) Viewed 4068 times
I know what the bolt spacing is on the header pipe, and the OD of the header pipe. I can scale out the other diameters and lengths of the rest of the system from that. It won't be super precise, but close enough. One problem, though. I haven't been able to source (online anyway) replacement mufflers that have an 1.625" to 1.75" OD inlet/outlet and a small outside diameter and short length.
Anyway, I'm going to look into finding a local shop that can roll the cones from my drawings. I can do the welding myself and see what comes out of it.

Tom H.

Re: Can a Expansion Chamber be built for....

Posted: Thu Sep 17, 2009 9:44 am
by white_ferret2002
I have a 72 bridgestone dirtbike. I was looking into a few things for that. I don't know if this helps but i found this info. Although you probly already have this info. or this info may be no good for the lj and only for the bridgestone i have. Just thought it wouldn't hurt to share

http://www.bridgestonemotorcycle.com/do ... eally6.pdf" onclick="window.open(this.href);return false;