take a look at Shindiawa 4stk. it has some good tech and is pretty light in weight. has unique induction system, charges the intake thru the crankcase much like a 2stk which has a supercharging effect then the intake charge is channeled to the intake valve, ign. takes place then expelled thru the exh. valve. they seem to have good power. there was 1 on sale in rcu buy/sell eng. section but i think it has sold, haven't seen it there for a little while. check ebay outdoor/garden section sometimes you can find 1 there. how they mite do on gas/glow i have no idea. like to try one and see what happens!!!! keep 'em flyin', fujiman

one more thing on the shin. 4stk. they run 2stk type mix gasoline, no crankcase oil. they can be run in any position, even inverted which make them pretty flexible. can't remember what sizes they come. i do remember a 25cc was available. maybe a larger displacement one is now available????????