440 Kit

[gixer_boy99]

I was wondering if I would have to run race gas with a 12.5 piston in a 440 kit? I have 11.1 with a sparks timing advance and I run 91... Let me know...

[Wheelie]

Yes.

[christophere251]

im running 93 with a fuel lube and my 440 runs exellent its 12.5-1 also!

[lil p]

you can run what you want. c-12 and alchohol are the best fuels but thats for serious racing.i run alchohol and it does great. i have alot more in my motor though.

[440ex78]

i would defently run 110 octane in the 12:5:1 i ran 93 and blew the head gasket

[bansheemorphine]

do you have to mix race fuel with regular gas? or what?

[GPracer2500]

Originally posted by christophere251
im running 93 with a fuel lube and my 440 runs exellent its 12.5-1 also!

I'd be curious to know how much cranking compression you've got that is allowing 93 pump fuel.

[Chin_Chilla]

I have a 440 Kit with a 12.5:1 compression, I was running 93 and 100 octane and having deto. issues. It all stopped with the second tank of VP-C12. I highly recommend it with this kit.

[300EXrider356]

so a 50/50 of 93 and 110 will not be good enough?

[GPracer2500]

Originally posted by 300EXrider356
so a 50/50 of 93 and 110 will not be good enough?

It depends--maybe, maybe not. There are a whole host of factors that go into an engine's required octane rating. The simplest way to figure out what's what is to make an educated guess about what fuel you'll need to run and then test it for signs of deto in your engine in your riding environment. What worked for Joe Blow may or may not work for you.