Aviation fuel in CRF

[damagedgoods]

I have a airfeild right around the corner from me that sells shell aviation fuel for 3.10 a gallon. Will it work good? As Good as U4?

[novaman64]

U4 is oxygenated gas. AV gas is just higher octance. So no.....

[Loopole]

there is some good reading if you do searches for aviation fuel, my impression from what i have read, av gas is very stable, has lead which is good for valves, is slightly oxygenated, however its burn characteristics are not targeted to 12000 rpm engines, it will not hurt your bike or fuel system, mix it with 92unleaded 50-50 and give it a try, but its not u4.

[Rich_Rohrich]

av gas is very stable, has lead which is good for valves, is slightly oxygenated,

US aviation fuel is not oxygenated, and unfortnately the lead in it won't help with the CRF valve face recession issues, but it is much more consistent than normal pump premium.

[dirtmachine]

Are you sure Rich? I'm pretty sure they add oxygenates to it in order to help it burn at higher altitudes. The fuel is not quite as good as U4 and I don't recommend you use it in your dirtbike.

[Rich_Rohrich]

Are you sure Rich?

Yes I'm sure. ?

100 LL AvGas contains Xylenes, Toluene, 1,2,4-Trimethyl Benzene, Ethyl Benzene, n-Hexane, Cyclohexane, Benzene, Tetraethyl Lead. None of these are oxygen bearing components.

[mauricio]

I´ve had my CRF250R since May, and am running straight avgas from day one. It is ridden hard every weekend. I did not break it in, I just ran it hard from the beginning and it does not burn any oil.

Carburetion is perfect and very consistent: JD Blue needle on 4th groove, 172 main, stock pilot.

I have checked the valve clearances three times and they haven´t tightened one bit.

I´m not saying this is because of the avgas, but I believe the lead might help.

Regards,

MAURICIO