What Octane fuel do you run?

[Mittzy]

Lushy said I should use 98 all the time but if I can not get 98, 95 will do. Brutus has been tuned for 98.

 

[Lemieuxfan]

interesting discussion; I am fortunate enough to have a non-ethanol gas station nearby and I always fill my Roadster with Premium No-Ethanol fuel; because our bikes are fuel injected I believe the higher octane will do a better job of keeping the injectors clean. To each is own; I've heard valid arguments on both sides.

 

[Rick McC.]

90 octane ethanol-free for me.

 

[Bedifferent]

I always use mid-range 89 even though I know it will run fine on regular 87.

 

[sonny]

My bike is stock, so we have been running 87 octane (pure gas) with no problems at all. My car and other motorcycle both require 91 octane. I stick with what the owners manual suggest. The idea of using 87 octane in something like the rocket seemed very strange at first. Wow all that power and cheap gas what a deal !!

 

[Tripps]

It's irritating that they only sell ethanol-free in premium around here, if you are tuned for 87 octane, you will lose a small amount of horsepower running higher octane.

 

[sonny]

Thanks for the info. Did not know that but it makes sense if you think about it.

 

[Claviger]

92, always.

I should add though, I run a custom map with tons of extra ignition timing so the extra octane actually makes sense for knock safety. On a stock tune, I would run 87 exclusively.

 

[crashpete]

I always use 87 in Arizona, stock bike, no problems or pinging yet.

 

[UberR3]

Running higher octane fuel than what your engine and its current tune are designed for is wasteful and can potentially be dangerous to your system. With higher octane fuel, the timing is such that not all of the fuel is burned and is wasted out the exhaust port. The unburnt fuel ends up clogging up things like cat boxes, O2 sensors, etc.

Our Rockets are not harleys (thank God) so unless you've had some extensive mods made running Premium grade gas is bad. Just bad.

Incorrect. Octane rating is simply a measure of the fuel's ability to resist detonation (not to be confused with pre-ignition). It has nothing to do with how complete the fuel/air mixture is burned or how much is wasted. Running a fuel octane higher than what the engineers recommended will NOT harm the engine in any way but it is a waste of money if the engine is not setup to take advantage of the fuel such as running high compression or advanced timing.

You always want to run the lowest possible fuel octane in the engine that it can safely withstand without signs of detonation. Otherwise, it is perfectly safe to run high octane fuel in these bikes if you want. I generally run 92 octane fuel simply because of the summer heat and I hammer on my bike a lot with periods of high loading at lower rpms where detonation is more likely to occur. Honda engineers did a really good study of fuel octane and engine rpm years ago which showed that detonation is only a concern at lower rpms levels and high engine loading.