Materials for 2 stroke expansion chambers

Hey, I am building my rd350 engine and would like to hands on on a pair
of tuned exhaust. Anyone has good experience on building 2 streok
exapansion chambers. Psl share with me. Thanks!

KM

 

Search for a copy of "The Two-Stroke Tuner's Handbook", by Gordon Jennings.
First published in the seventies, IIRC.

Ed Cregger

 

You can build one I suppose, but you should really consider buying one. The
amount of engineering you need to do just isn't worth it even if you valued
your time at $0.50 per hour. You would be time, money, and effort ahead
getting a part time job to pay for toys. Let the engineers with the
modelling programs, dynos, and more do what they have trained for years to
do. Just reap the benefits.

pierce

 

Jennings book provides schematics for different expansion chambers and the
geometry/algebra needed to change them for different applications, IIRC.

Some folks just like to build things. I do.

Ed Cregger

 

I had one of those new, back in '74 or so, and fitted a nice pair of
expansion chambers made in the USA - I had to go up a *lot* on the carb
jet sizes. They were made out of mild steel, painted black, and tended
to rust rather badly. A lot more power (and noise)resulted. They had
glass fibre packing in the outlets, to make them a bit quieter.

Leon

 

I'm working on a '74 RD350 right now, and have almost a complete parts
bike if you end up needing anything for it, post here and I will see
if I can help. In regards to your post, I have an extra set of the
chrome stock pipes if you give up and need to replace yours.

Monk

 

It could be that i am wrong. Maybe they are easier to make than they
look.

pierce

 

Production racers in the late '70s-early '80s found that the
stock RD mufflers made pretty decent expansion chambers. They just
cut off about half the length of the stock baffle tubes. That, along
with some cylinder porting and proper carb jetting, gave a pretty
respectable power increase.

 

Only if you want them pretty and you have the necessary gear. <G>

Ed Cregger