Regular, Mid-grade, or Premium fuel?

Not sure the best category for this question, but here goe's anyway... :whistle:

With stock engine (pistons, cams, carburetor), is the best choice to use Regular gas? If not, what advantage has another grade over it?
My engine spec compression is 8.9 to 1, whatever that means. Whatever does that mean, anyway?

I have always used premium fuel in my bikes. Even when they were stock. I seem to remember stock bikes called for 89 octane or higher for KZ 1000s, but that was a long time ago.

Is it a waste of fuel (and money, of course), if not needed for good combustion? And, if the compression ratio doesn't warrant using Premium, doesn't some unburned fuel blow out the exhaust, and carbon-up the spark plugs?

daveo wrote: Is it a waste of fuel (and money, of course), if not needed for good combustion? And, if the compression ratio doesn't warrant using Premium, doesn't some unburned fuel blow out the exhaust, and carbon-up the spark plugs?

It won't hurt anything to run premium. My bike never ran right on 87 octane, I think 89 is OK, but higher than that isn't necessary.

Around Houston...all grades of fuel have ethanol added...which means you lose, no matter what grade fuel you select.

daveo wrote: Not sure the best category for this question, but here goe's anyway... :whistle:

With stock engine (pistons, cams, carburetor), is the best choice to use Regular gas? If not, what advantage has another grade over it?
My engine spec compression is 8.9 to 1, whatever that means. Whatever does that mean, anyway?

8.9:1 compression - Is this a Harley or an old Kaw that needs a ring job? :laugh: My KZ650-C1 is 9.5:1. Ed

1982 KZ1100A compression ratio according to the shop manual.

1075 and up high compression engines can benifit from 25% off racing fuel on a fill up. will run cooler, cleaner and faster.

With the questionable quality of fuels, with all 3 grades coming out of one blending nozzle at most pumps, and all pumps no longer have the lead our motors were designed to have I will keep using the best fuels I can find and afford rather than save a few cents on a average 3 gallon tankful and risk hurting my investment. Just like quality Oils. Peace of Mind has its own value.

To each their own.
Dave

I've always ran 89

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