CB/CL 350 RACE BIKE FAQ EXHUAST MODIFICATIONS PAGE
- Chris Marshall, Exhaust modifications: I use an exhaust I built myself. It has
1.5” headers with a 22” primary length. Mufflers are tapered meggas with
no reverse cone, 30” long expanding to 3” diameter. To quite them down
they have an external absorption type muffler. Never tighten the header
nuts too tight, leads to cracking. Rubber mount mufflers too.
- Hoyt McKagen, Use formula: Length = 204,000/.85 X redline, and thank Jim Schneider for
this every time you fire it up. Length is from ex valve seat, so actual pipes are
shorter than indicated. Pipes should start exactly at port size and
increase about 5/16-3/8" in diameter in whole length, preferably
proportioned as an exponential curve. These pipes make more power over a
broader range than can be imagined and the exact taper isn't really
critcal. If a meggaphone is used it needs to be 85% of primary len and have a 45
deg reverse cone stepping down to maybe .75 of megga exit dia; actually I
think two shorter reverse cones spaced a couple inches apart and with
diverging diameters would be even better. If silencer is used, the pipe
must enter for some distance and the silencer contour there must be
bigger and distinct from the end of pipe. Anti-backflow headers a la Jim Feuling
give a definite advantage. Steeper tapers on pipe and megga give peakier
motor.
- Chris Ford, The only exhaust modification I made was to go to a two into one
collector pipe. Better ground clearance, less weight. That was pre-WERA
Belly Pan rule (Year 2000) so make sure any mod in this area can also
accomodate a full motor length/width belly pan.
- Buff Harsh,ALL exhaust systems for the 350 are custom made and all are different in
some ways. There is no right or wrong setup here... I have seen 2 into 1
work great as well as 2 into 2. The Jemco megaphones seem to be the standard route
but the welders out there have their
own ideas. I will say that shedding the weight of the stock headers is a
good idea if you can make something else work.
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