wat psi do you run a race gas/peruim gas blend

BlasterCrazy

New Member
Dec 31, 2008
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Michigan
I have a aggressive trail with boyseen reed sheer pipe and a 35mm keihin airsticker put the motor together did a squesh test witch was .62 thousands my builder say that right and i would be runnin 140 psi and i should run a 50/50 but at 140 psi sound right to run 50/50 blend
 
well it is more than just psi, what is your CR, are you going for a high rpm engine because a 35mm is way to big for a trail port stock CC motor.
 
I've heard that about 165 psi is the limit for premium fuel but shee blast (as much as it pains me to say this) is right, it's about more than simply the pressure inside the cylinder. It also has to do with hotspots inside the cylinder, ignition timing, swirl and atomization. You can get an engine with 130psi cylinder pressure to detonate using premium fuel.
 
I ran a 34 with a mild port for long time. carb size should be ok. 140 should be fine for premium. I wouldn't startworrying untill you get up around 170... even then I have ran around that with premium for perunning and 50/50 (75 race/25 premium when it got hot in the desert) wthout problems.
 
i am was running 160psi with my cut head done by ken oconnor and he said premium is fine. (93+) i ran 94 for the little time i rode it, aka 5 minutes... stupid crank bearing