I called the guy i bought it from and he used amsoil(i think thats what he said the brand was) 100:1 synthetic. He said it's hard to find but it's worth it because the engine runs much smoother.
I'm not yet willing to cough up the money for a new bi-turbo ($150 at http://www.mopedworld.com/PerformancePuch.htm)
How would i go about milling the head for more compression? We do have a machine shop, even in this tiny (home of the atomic bomb) mountain town, i could go to.
Thanks!
roger