best octane to run in bike??

[kparkfan]

was wondering what the best octane is to run in a bike. ive heard the higher the better. any input?

[Baatfam]

I run Regular unleaded, (87 around here), in the red bike...
And 110 leaded in my fast bike...

And no, higher is not better...run the lowest that works...

[Steve]

Unless you have changed bikes since I saw you last, NO.

Stock bikes (even ones with pods and pipes) run best (in most cases) on 87 octane, REGULAR gas.

There is no extra power in higher octane, in fact, higher octane fuels have fewer BTUs per gallon. Advancing the spark does not give you more power, either. Both of these 'tuning' items, high-octane fuel and spark advance, are band-aids to make up for the problems introduced by high compression, which is what really makes the power.

Higher compression generates more heat which might light off the fuel mixture before the spark. Higher-octane fuel will resist that because it's harder to light and waits for the spark. It also burns slower, which is why you have to advance the spark to start the fire earlier.

If you run higher-octane fuel (notice that I try not to call it 'premium' fuel?), it will not be completely burned before the proper time, which will probably lead to deposits on your valves and pistons. These deposits will cause problems because they can glow red-hot, lighting the mixture before the spark.

Until you get into changing the pistons and cams, REGULAR gas is just fine.


edit: I see that Baatfam posted while I was typing, and had pretty much the same info. Now for Rapid Ray and some of the other racers to confirm.
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[kparkfan]

yep still have the same bike. id rather keep using the cheaper but still to damn high gas any way.

[trippivot]

I say stay away from ethanol blend fuel.

I run the regular non ethanol 87 octane even in a 10.5-1 engines

octane is a pressure resistance number. higher octane the less volatile the fuel.

[Baatfam]

I say stay away from ethanol blend fuel.

If I could....but I don't want to drive 2 hours everytime I need to fill up...

[flyingace]

I run 89-90 just because the bike seems to run better with that grade. If that's the result of less volatility, then so be it. Being a stock bike, it tends to run lean, and an air-cooled engine will run hotter than liquid cooled. This combination is a setup for pre-ignition, which I try to avoid.

[tkent02]

I run 89-90 just because the bike seems to run better with that grade. If that's the result of less volatility, then so be it. Being a stock bike, it tends to run lean, and an air-cooled engine will run hotter than liquid cooled. This combination is a setup for pre-ignition, which I try to avoid.

Why not richen it up a tad?

[C.V.]

I recently tested premium vs regular, ran premium for about 4 tanks, then back to 87.
Conclusion - 87 octane all the way, much more power and much better response from the lower octane fuel.

I was initially fooled a bit by the first tank of 92 octane, as the bike seemed to run a bit smoother, but I was delusional, the power loss from the 92 was very noticeable after I switched back.

Make more power and save money, use 87.

[mixongw]

I recently tested premium vs regular, ran premium for about 4 tanks, then back to 87.
Conclusion - 87 octane all the way, much more power and much better response from the lower octane fuel.

I was initially fooled a bit by the first tank of 92 octane, as the bike seemed to run a bit smoother, but I was delusional, the power loss from the 92 was very noticeable after I switched back.

Make more power and save money, use 87.

I thought it was my imagination but mine does run better on 87 than 93. I do have to make sure I keep the rpms up with the lower octane to avoid pre-ig.

[Grandpa]

GK with 132,000 miles, (plus the 2,000 or so Josh has added) -- not one drop of anything except 87-octane unleaded, in the 9 years I owned it.

Brand of fuel doesn't matter either. I always looked for the cheapest gas I could find. Not one bit of difference in the running, ever.

[Steve]

I can't quite say that Grandpa and I have done the same thing.

I have to total my miles over several bikes, but the total is over 200,000 miles. I have put other octanes in, sometimes as a trial, sometimes out of necessity. Pulling a trailer across Oklahoma and Texas with my Kaw Voyager in 100+ degrees was making the engine ping quite a bit, so I ran 89 octane to quiet it down. Also, I have found that in higher elevation, "regular" gas might be 86 or even 85 octane. Works fine in the upper elevations, as long as you burn it off by the time you come back down.

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[flyingace]

Why not richen it up a tad?

Because I get around 46-47 mpg and the bike runs great. I need a better reason than switching octanes to mess with the carbs. Besides, it runs fine on 87, just not as fine.

[tkent02]

Because I get around 46-47 mpg and the bike runs great. I need a better reason than switching octanes to mess with the carbs. Besides, it runs fine on 87, just not as fine.

It might get better mileage if it was not too lean, these were set at the factory for emissions, not gas mileage.
Twenty some years later gas is different now, as is your engine.