Brian, I run 93 octane Amoco with non-synthetic 2 cycle oil with a ratio of 3 oz. oil to 5 gallons of fuel. Discussed with the Hondo motorcycle tech people about synthetic oil and they don't recommend it because of the carbon build up they see on their 2 cylce racing enigines. I get a little smoke when we first crank up but as the exhaust temp rises, the smoke goes away and we have a good clean burn on the plugs. In fact I change the plugs every year whether we need to or not (lol). Hope this helps you out.