Newbie gas question

[owenxguo]

I'v been doing auto racing for long time and recently bought myself a kart and thinking of playing with kart from now on. What I have is a Kosmic 125cc shifter with Rotax, the guy who I bought it from told me to use 100 octane race gas mix with 2 cycle oil, but since I do lots racing on my car and normally with higher octane gas left(like 114 and 120 leaded), I was wondering can I use with the higher octane gas or have to be 100 oct? Also any suggestion on gas/oil mix ratio if just doing lap days and wants to keep the motor last longer?

Thanks and happy racing

[Taddzy]

i do know if your racing at a high level that the fuels are controlled!! as higher octane fuel as far as i can remember will give a bigger explosion meaning more power but i think i am right in saying can cause more wear on the engine meaning that rebuilds will be more frequent

[owenxguo]

I thought so too, because on my track car I normally go higher octane to make motor running more reliable, but when i asked one of my kart friend, he said no, that kind confused me so I am asking here.