Hey there all you 2 stroke brainiacs! I am building a dunecycle here in Seattle and need some exhasust and expansion chambers for a kohler k440 2ams. I have a local fabricator but after extensive reading up on expansion chamber design I thought I better ask if anyone has done this before. Can anyone be of assistance?
kohler 440 2ams exhaust/expansion chamber dunecycle
Sounds like a death trap. You can't move your weight forward to keep the front end down. Sounds like fun!!! My advice is to get expansion chambers from a Kohler 440 snowmobile, and cut and reweld to fit. They came in several sleds. Mercury was the most popular Kohler sled. Sno Twisters had twin pipes and Trail Twisters had single pipes. Polaris and Speedway also had Kohler motors. Not sure, but Arctic Cat might have used them as well. I'd suggest a single pipe, since you won't need top end power and high RPM's. Try a C/L ad in Wenatchee for pipes. If you can't find anything there, try this site. Vintage Snowmobiles Classifieds on VintageSleds.com . A roll bar and a helmet might be a real good idea.
All parts of a 2 cycle pipe affect its performance. The length of the header pipe, length and angle of the diverging cone, Mid-section(if used) and converging cone length and angle. They all affect how and when the pipe hits its tune. Its a real science to the design. Even using a pipe like Screamer820 said may work ok but may not. Their tune is for the snowmobile which may be ok as their drive systems are similar.
Check your local offroad bike shops or even micro-sprint race tracks if you have any. There is bound to be a "Mr. 2 cycle" around that can help set you straight.
Check your local offroad bike shops or even micro-sprint race tracks if you have any. There is bound to be a "Mr. 2 cycle" around that can help set you straight.
Check out this online Calculator MOTA 2 stroke engine software
And Jenning's is the guy for pipe making.
Gordon Jenning's Archivek
And Jenning's is the guy for pipe making.
Gordon Jenning's Archivek
I would assume that he would just cut and rotate the pipe to fit. It would be fine if he does that. If he cuts sections out, it just may run goofy. The shorter the pipe, the less torque it will have. A fatter pipe will make it "pipey", which means all the horsepower will be at high RPM's. Race bikes or sleds with two strokes, have short and fat pipes. One for each cylinder. They are too difficult to ride on the street. An everyday two stroke sled will have a long and fairly skinny pipe for more low end torque. Two stroke street bikes have two long and skinny pipes. There were a lot of racing go karts, outboards, snowmobiles, and motorcycles made with no expansion chambers at all. Just straight pipes. They ran just fine that way, but a little better with the pipes. In any case, his trike will be just fine with whatever it ends up with. Should have way more power than it will ever need at all RPM's. A Kohler 440 should have at least 50 H.P., and the trike probably came with 5 H.P. That's 10 x the original power, so it will rip no matter what pipes are on it.
I wanted to thank you for the moto software idea...it looks like thats the best one i have seen yet. I am meeting with my fabricator tonight to show the software to him...again thanks...btw the original dunecycle i have came in two stock options a kohler 293 single or a 340 twin cylinder. I had a 27hp 293 as a kid in alaska and it was a blast! and you were right the 440 is rated at 50hp...hence the plans for stretching the frame, moving the engine forward, seat back, heavy dutie roll and nerf bars and...a good helmet!
