I have the urge to fuss with an engine. I have an ECHO 65cc that I have already converted. I would like to optimize it. I have not measured anything. I am using an RCEXl ignition. I did add a big carb and a free flowing exhaust. If forget the prop and RPM but, it produce about 30# of thrust.

Generally speaking, what should the port timing be for maximum power?

Anyone ever make a tuned pipe from scratch? I was thinking about an aluminum beer bottle or water jug. How do I calculate the volume needed? How important is the angles of the expansion chamber walls and the reducer at the end? Is there a secret to getting the heat resistant tubing to connec the header to the pipe without paying a bunch of money? Do auto parts stores or bike shops have a kind of tubing that will work?

I was hoping to make a trombone like affair that I could adjust and try to see what volume works best.