will this work with my 440x

[atvnka22]

hi i just got a 440ex with a stage 2 hotcam,aftermarket valves and rockers,new cluch,and a new racing crank, and i was wondering if i could run like 93 bc i ride a few times a week and the guy i boaught the uad from has been runnin like 112 power mist and it is like 65, 70$ for 5 gal's and thats carzy bc i can go threw one or 2 of thoes in a week,so i was wondering if i could like mix 93 and like 110 with a 50/50 mixture or i can like jusr run 93 or somehting bc it is ay to much to run full 110 gas.or i was wondering if i could get like a lower comp piston and run 93 bc i think i have a 12;1 440 piston in it now. THANKS

[pual0101]

yes i think a 50/50 mix will work for you right now, but yes if you drop your compression to 11-1 you can run 93

[krt400ex]

Originally posted by pual0101
yes i think a 50/50 mix will work for you right now, but yes if you drop your compression to 11-1 you can run 93



x2

[yfz450admirer]

I had a Trinity 440EX with 12.5 : 1 compression. I put a ton of hours on the machine and only used 91 octane. One time I put 100 octane in it and there was no performance change.

[GPracer2500]

Originally posted by yfz450admirer
I had a Trinity 440EX with 12.5 : 1 compression. I put a ton of hours on the machine and only used 91 octane. One time I put 100 octane in it and there was no performance change.

Conversely, my JE 10.8:1 knocks like crazy under load with 91. I'm at one extreme, yfz450admirer is at another (91 with 12.5:1 and zero deto is quite unusual)....

Different fuels (we don't typically know the MON rating of pump fuels, only the R+M/2 rating...91 in one place can have a different MON than 91 in another place...and the MON is what really matters the most), different cams, different elevations, different jetting preferences, different gaskets, different ignition timing, and a bunch of other stuff all make a difference in determineing an engines required octane.

All that aside, 12:1 static compression in an air-cooled engine is very likely to need more than 93 pump. But the only way to know for sure what your engine requires is to test. Put in 93, find a long steep hill, make sure the engine is nice and hot, and try lugging the engine up the hill at WOT. The goal here is to put maximum load on the engine. Listen for detonation (i.e. "knocking" and "pinging"). If you get that then start mixing pump and race until you find the minimum ratio that doesn't deto. Try looking for something like VP Red. For a "race fuel" it's inexpensive and has a MON of 105. I gather that for your purposes the least expensive high octane fuel will be just fine.