So I now have two Rotax max karts and I have one up and running which I drove for the first time last week. I use 110 leaded Sunnoco fuel in my motocross bikes so I have that on hand and used it with 6oz of Motul Grand Prix synthetic kart oil per gallon. It seemed to run fine but did seem a little rich. Question is what is the best option for fuel/oil for this engine. I don’t want to be using my $12 gallon race fuel if it is not necessary. I am just out running laps on open practice days.
Mine ran grezt on 93 octane pump gas. I want to say I ran 40:1.
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3oz to the gallon. Just run the XPS stuff if you can get it. Try 93 octane pump gas if you’re just turning laps for fun. Go on pure-gas.org to see if you can get ethanol free fuel. Otherwise do not let the fuel sit in the carb, lines, or tank for long.
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From the BRP-Rotax manual:
Mix fully synthetic two stroke oil at 50:1 with 95 RON (91 AKI) gasoline.
BRP recommends XPS Synthetic oil. Motul 800 has also been extensively used in the Rotax Max engine.
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Just this weekend spec fuel was Sunoco 95 octane for reference.
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Thank you. I assume this is unleaded. I’m sure they have it where I get my Sunnoco 110.
Yes, you can get premium gas at most gas stations (outside of rural Ohio and Kentucky)
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The premium gas is here in CA has ethanol in it 
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Yes. It’s a performance-enhancing chemical. If I use pump gas against drivers who are running leaded, nonoxygenated race gas the tech inspector will have a good reason to disqualify me.
That gas with ethanol came from the devil, any chance of starting an engine with a carburetor is doomed if you leave it more than a month with that stuff in there!
Yes. That’s why you don’t leave it in the carb. At the end of the day take the bottom cap off the carburetor and drain it.
I don’t know of any fuel/oil mix that you can get away with leaving in an open carb bowl between races without causing engine failure, even avgas and Motul leaves behind gunk.
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