What octane is best?

[Tryzeedudeman]

I have recently had some porting and polishing done to the jug and shaved the head a bit. I have the full dg exhaust, 38mm mikuni, k&n air filter, boysen power reeds. All i can really find is 93 octane. How much of a difference would some 110 octane racing gas make for me. And for some reason, when i get into sixth gear on the sand it didnt want to go through the gear. I do have a 14 tooth counter sprocket on it. Could that be the cause of this. Thanks

[Tryzeedudeman]

O.K. well how bout just telling me what octane you use in your 250 2 strokes.

[Merge_88]

The guy I got my Z from claimed he had been using a 50/50 blend of 110 and 93......who knows for sure though

[TJ BIG DAWG]

110 is what I run in my 350X but it has 13.5:1 compression...on my 2 strokes 93 is fine unless you have shaved the head more than .020....but your 6th gear prob sounds to me like gearing but you didnt say how many teeth are on your rear so I couldnt say for sure.

[MOTOMAX27]

What is your compression?? I use C12 its 108 oct. from VP

[Tryzeedudeman]

dont have a compression tester but the head is shaved and the top end is fresh and it runs great(neck and neck with my bros '04 660 raptor 2nd gear through 5th). I'm assuming the rear sprocket is stock gearing whatever that may be, couldnt find it in the manual.

[MO350X]

The rule of thumb is to run only the octane your motor NEEDS.
No higher.
Why?
High octane fuel burns much slower.
It will produce less power if your motor doesn't have high enough compression (heat in the chamber) to light it properly.
You always want a fast hot burn, never a slow lazy burn that CAN lead to plug-fouling.
Besides, spending big bucks on race fuel when it's completely unnecessary is silly.

You really need to get your hands on a compression tester.
They're not expensive.

110 octane fuel south of St. Louis:
Pevely, MO-HUGE truck stop (McStop) that sells it to the local roundy-round folks for a little over $4/gallon! I haven't needed it in years but called them the other day (for my turbo dune buggy) and that's what they said. That's a smokin' deal!
South County-Butler Hill/Lemay Ferry has the same 110 but it's over $5/gal..