Fuel type

[efilnicafesin]

I've got a 87 250x I just put a 12:1 Wiseco piston .50 over, with a stock cam, FMF Megamax 2 pipe, uni filter and one heat range colder spark plug... My main jet right now is a 135... I am still kinda in the break in stages with it, but it seems to run well. I had some 87 octane fuel in it , and I topped it off with 93 octane. I was told by the bike shop that bored my cylander that I should be running either 104 octane boost, racing fuel or avaition fuel... I am not getting any predetonation now. What do you think? Will I see much a difference if I run the higher octane fuels? Does my jetting sound about right? I haven't looked at the pilot to see what size it is or where the clip is at yet.... I'm gonna change the oil and retorque the head this weekend..

[400ex men]

i wood say that it wood but

[Ryan]

Definitly use a higher octane fuel. You may not notice the predetonation, but when your motor overheats and your short a grand to fix it, then you've got some problems.

[efilnicafesin]

OK... so it is more for engine temp/colder combustion issue than a performance issue. I guess an oil cooler would be a worthwile investment? I've been doing some reading about them.. :D

[Toadz400]

The higher octane gas isn't for performance wise if you're thinking major HP from it. It's just so that it doesn't kill your engine later, it will run smoother because you won't have any pre-detonation anymore...but you probably won't notice anything if you say nothing is happening now. Also an oil cooler would help with keeping the temps down.