I thought the compression was too high on Harley's to run anything but premium...on the nighster I use to own, I accidentally filled the tank with regular once and I did notice a difference, negative...I've never tried regular on the bob...

 

Premium only in mine.

 

I tried running regular once and my Bob ran like crap. Since then I've run premium 99.9% of the time plus a tank or two of mid grade when premium wasn't available.

 

Cannot get regular here in Germany. Nor to they sell that ethenol junk here either.

 

Premium. Never tried regular, and I have no idea if it would make any difference at all. My car needs premium so it's just a habit anyway.

 

exactly

 

Had to use regular in my bike once (out of prem and no other stations close by) and the motor pinged like crazy..

 

Same here. I've always ran premium in my bikes, except for my Suzuki V-Strom, that bike hated premium. It's just such a small price difference, I figure what the heck.

 

You'll actually get b etter gas mileage with premium. That's the case with my Jeep. I'm sure my bike gets better milage with premium too.