better gas

[Anonymous]

i was just curious if anyone knew if its better to run high octane in two stroke engines?

[earlfor]

Re: better gas

Octane requirements are primarily dictated by compression ratio and most 2 strokes have fairly low compression ratios. So, there is no benefit in using high octane gas. (other than getting rid of some extra money) :-) :-)

Earl

i was just curious if anyone knew if its better to run high octane in two stroke engines?

[Anonymous]

My 83 CR250 required the good stuff. My friends Banshee used high octane too, so did his 125 CC bike.

Steve

[Anonymous]

gas

My first bike was a 77 Yamaha RD400, two stroke twin. It ran better with 87 octane even with a jet kit and tuned pipes. I tried them all, even with octane boosters and it always responded better with low octane. Use a good low ash oil too, like Bel-Ray or other name brand. Don't run chain saw oil in it! The heavier oils will in effect lower the octane rating too.

Later

[TheNose]

The Octane number is basically the gas's ability to resist combustion. That's why you need a higher octane gas for higher compression engines. So it won't ignite too soon in the compression stage. Being that these engines don't have very high compression, it won't help at all.

FYI - Octane is measured in two ways. One way is using a knock engine or motor. This gives you the Motor Octane Number. The other way it is measured is in the lab using instrumentation. This gives you the Research Octane Number. The Road or Pump Octane number is the average of these two numbers. If you notice the pump at the station, it should say the octane = R+M/2. (Or sometimes RON + Mon /2) Research + Motor divided by 2. I work on a Near Infrared Instrument that takes the place of both of the above types of measurements. It is able to predict the Research #, the Motor # and the Pump octane #.

Terry

[Anonymous]

Very intresing infomation. Once again I have leaned something in this forum I didnt even know I wanted to know.