[renegadespec1]

Trojan,
I went back and read trough the posts...and that was funny I just missed it...sorry
The java program is a great starting point, but sled motors turn a lot slower than most 2 strokes...example...chain saw...13,500...old 125 dirt bike 10,000...I don't know what the cox toys turned at but I'm sure it was 11,000 or better...Twin Sled motors are are all done at 8000 and under, you can spin a tripple over that but the clutches don't like it...The Java program was designed for a motor that will fit in the palm your hand...not for a motor that has a piston the size of your fist. I spent a boatload of time researching the air flow,shock waves and refractory pulses,and resonance before starting to roll my own pipes...I do use the java on the singles I build,as a baseline. I have a freind,whose into the nostalgia sled racing, the last motor we built for it went 78mph on the ice, it was a whopping 214 cc's pulling a 300 pound sled plus rider...No sno speed record but I thought pretty impressive for a sled Built in the early to mid 60's that had a top speed of under 30mph...getting the dimensions isn't that hard...Java has a good animation...The one thing that most guys have trouble with is the transfer port timing...I have miscalculated that on several attempts to build pipes...the peak goes one way or the other in a big hurry...one digit off and the pipes are junk....I fought with using stock pipes and hacking them up for years...since the 80's...I used to order up tuner pipes from PSI and cut them up to get the bends and the tuned pipe...I found it to be way easier to just roll the cones and belly, using the head and tail pipes to do the bends I need to fit them in the buggy...BTW..it does help, if you design the cage to accomodate the pipe area