Does gas octane make a significant difference. I have a 2002 Deuce (stock) and I have been running 93.I sometimes will get back fire when I let off the throttle. Will a lower octane (such as 87)make that much more of a difference?

 

The octane rating will typicallynot causebackfiring, assuming the gasoline is 'typical' 87-92 octane range. The question as to the value of higher octane ratings is an ongoing point of discussion 'round these parts. My experience with backfiring is either too rich a mixture and/or intake/exhaust leaks.

I personallyprefer the higher octane blends, especially for air cooled engines. Higher octane fuel burns more slowly than does the lower octane stuff, and thus disipates heat more uniformly.

 

Thanks ZD for the reply. Good call on the mixture. I noticed I was getting a pretty heavy residue on the exhaust and thought that my mixture was too rich.

 

Crossfire, do you know the part # of that little bag you've got on the front of the Deuce? It's the perfect small bag. Has it scratched the trees?

 

PM's ya nine11c2

 

octane is an additive.no it doesnt mean your fuel will burn sloweror faster.the rating you see ,87.89.91.93, ratethe fuels'resistance to pre-ignition.in other words ,the combustion chamber can get so hot that no spark is required to ignite the fuel (you will hear pinging).the more octane the fuel contain the more resistant it is to this preignition!so on a super hot day your fuel will not flash ignite on its own.preignition can cause you piston and valve damage.imagine your piston still moving up on its stroke ,then boom preignition,the collision may blow thru the piston,or even back up the valve seats,burning them up.got it!!!!!