440 kit- do i have to run racing fuel even if i get a bigger oil cooler

[speedy]

Well, i was wondering sence ever one on here is saying sence the 400ex isn't liquid cooled you have to run racing fuel in it if u put up 440ex kit in it, so if i get a bigger oil cooler could i run the regular pump gas??:confused:

[Crawl69]

the only reason that you would need to run race gas is if you upped the compression.

[tprender]

With the lower(less than 10:1) piston you can run reg gas. with the 10 to 11:1 piston you need to use 50/50 mix. And above 11 it has to have race gas. the oil cooler has nothing to do with the fuel mix, I think.

[cals400ex]

from what i read its not the oil that needs to be cooler. sparks claims it is just the 400ex engine that is begging to be liquid cooled. i don't think the cooler will help much. however, i am running a 10.8 compression piston on my 400ex without a cooler or bigger tank and i use premium pump gas. the bike runs good. i have never tried race fuel.

[mxracer111]

****first and last warning for advertising*****

[skemp]

The oil cooler will help with preventing detonation by keeping the overall engine temperature down. What compression will you be running? If you will be running lower than 11:1, you might be okay with the oil cooler and premium pump gas, but if it still runs hot or pings, you will need to mix a little race fuel in with the pump gas.

[speedy]

The 440 kit im gettin comes with 11:1 compression ross
piston :cool:

[RED121572]

Im not mickey dunlop, but take my findings for example.

I ran a 11.1 406 for a year. I took oil temps after just about every ride. Under extreme conditions, the temp would read 215-220. Normally, it would stay just BELOW 200.

With the 435, 12.5.1 piston, race gas and jetting changes...the temp is at a constant 215.

You may want to at least consider a bigger oil tank.

RED