Cannondaleriders

I used 87 octane in my bike this weekend and it ran like crap. I'd like to blame the gas, but can it really make that big of a diffrrenece?

the sticker on the bike says dont use less then 91 or somethin like that so blame it on the gas

Has to do with how clean the gas burns. If it doesn't burn clean enough you end up with lots of deposits and reduced effeciency. Ergo, runs like crap!

Too low of octane rating can cause predetonation, the manual says it requires 93 octane so I would at least use 91 or higher.

Not an expert but the octane rating is more or less a measure of how stable the fuel is , so a higher octane fuel will not ignite as easily under pressure as a lower octane fuel this is why higher compression ratios require higher octane levels. The knocking that comes with low octane fuels and high compression ratios is actually the fuel exploding under pressure as it is compressed before the piston comes to the top and before the plug ever fires this is why you feel a loss of power,the energy of the rotating crank/flywheel is being used up fighting the preignition that is trying to push the piston down . Again I'm not an expert but this is what I understand from the reading I have done and the experiences I've had.

maybe i was on crack....sounds correct to me.

As I understood it, the higher the octane the longer the fuel burnt. And low octane caused pinging becuase the fuel flaired quickly before the piston got far enough into the down stroke. ANd High octane delivered a more even explosion..
Anyways, the overal lesson I believe is, 87 octane may make your bike run like doodie....

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.

I run 89 in mine all the time it seems to run pretty good I usually dont stoop to the 87 octane level. The 89 runs good so I run it all the time.

Is that why Jeremy beat your on a 450R last race?