John

Twins are a different animal. I have absolutely no experience with them except when I was on a consulting job in Texas. I ran into an old timer who had a Mac Minarelli on a giant scale PT-17 and he told me that he had to retard the spark to 40 deg. BTDC in order to start it. I didn't see him set the timing so this is hearsay. There may be other factors as well that I am not aware of.

Here is an excellent link to a Zenoah G-38 conversion to CDI ignition. [link]http://tech.flygsw.org/g38ignition.htm

It answers a lot of questions about timing and sensor placement for single cylinder engines.

AlZ