anybody got expansion chamber dimensions?

flying cycletruck

New Member
Local time
1:00 AM
May 17, 2008
San Jose, California
Hi all, I am looking to weld up an expansion chamber for an "80cc" happy time. I realize I could just buy one, but I want to do some fitting around the frame and it would be easier to start with a straight chamber. I've been looking at the various free software out there but haven't been able to get it to run on my computer. Those who have good working expansion chambers, could you post some dimensions? diameters and lengths of divergent cones and header pipe lengths would come in real handy.