ORIGINAL: Stick 40
I have ran 10% nitro in my saitos and never had a problem, mine are older saitos and I use a caster blend fuel.
Thats another thing, I always run castor blend on my engines. The other day one of the old timers told me I should not run castor in my 4 strokes because it will cause the valves to stick and that he has always runs full synthetic. Funny thing was while he was telling me this he couldn't get his engine started and it was determined he had a stuck valve
