octane

[nate b]

can you safely run like 92 octane in a 250r with 185 psi static compression.

[plkmonster2]

Yes, you can run 92 in anybike, no matter the compression, but you shouldn't run a low octane fuel in high compression engines. I think that 92 may give you a tad bit more power, but I'm not sure if it will really be noticeable...

[nate b]

is 185 high compresion

[plkmonster2]

No, I would think more in the 220-250 range is. I think 185 is more of an average..

[samster143]

185 IS pretty high compression. something around 200psi would be very high. With 185 psi I would be running something with at least 93 octane to protect against detination. my.02

[plkmonster2]

Oh, I guess I was off... In a two stroke though, shouldn't the compression be higher than a four?

[smokinwrench]

My R had 210 compression when my top end was new last spring, it now has about 190. I can run 92 octane with no problems even with 210psi of compression.

[deathman53]

I'm told anything above 11:1 you need race gas, I don't know how many lb's that is, but I used 93 in my atc250r with the cut head and stock head gasket with no problems. I wouldn't use 93 with a big bore, or anything more than 190 lb's.

[Wickedfinger]

That 185 psi compression actually falls into the upper part of the normal stock range. You should only be using 92 octane or higher in any 2-stroke for maximum performance. Hondas manual actually recommends 92 octane as the MINIMUM you should be running.

[ClayW]

What would be the highest octane you would wont to run in a 4 stroke 250 and 500 motor. Would 92 be a little better to run than 87.????

ClayW