I see a lot of threads of people using too much oil. This is not adviseable. If you use too much oil w/ out using a larger jet you are actually running leaner. Only so much mixture can go through the hole in your jet, so if you have a higher ratio, i.e. more oil in your gas, then less gas is going through (lean condition is the enemy of 2 strokes). So even though you have more oil you can still sieze your motor and even if you don't sieze, your motor will run hotter, you will probably lose power and you'll have to service your motor more often. The appropriate octane gas, burning properly will also regulate engine temp. I'll leave it open to others w/ more "bicycle motor" experience what gas is better, But I would think w/ only 6:1 compression 87 octane (regular) is best. But just as an example I built a Yamaha rd 350 w/ 70 hp, 10:1 compression (stock is 37hp) and ran 110 octane leaded gas at 33:1 mixture. More is not necessarilly better!