thanks for answering me on that i think i will try is i got 4 gallons today i also found some sunco race gas in town but its 6 bucks a gallon thank you

 

<< Av Gas is federally regulated. >>



So are all fuels.



<< , it comes down to the 4 strokes usually utilizing a higher compression ratio. >>



Not if you use the normal method of testing, by cc'ing the head/piston. The compression ratios of a KX 500 and a YZF 426 are about the same.



<< I don't believe anybodies engine is at stake here >>



If we were talking about a stock engine, I would agree with you. A modified (higher compression) engine can overheat and sieze a piston with aviation fuel.

 

if thats the case, one would think that my 250R with 240 PSI of compression (on a certified gauge) +4 timing advancer and retimed flywheel would sieze wouldn't you? but it hasn't and has been running for 6 months on av gas, as well as the LRD engine that LRD setup for av gas with 225 lbs compression before that...but it didn't either.

454: make sure you jet your carburetor to the new fuel. Some oils don't mix with av gas that great, you'll just have to find one that works for you, I personally use Yamalube. Have fun.

 

i am talking about race car engine builders using av gas for dyno testing and over 40 years of building and dynoing race engines i never had any problems running av gas.

 

As pete said I was told by my builder for my drag motor that I could get more performance and it wouldnt be as affected by subtle changes like race gas(such as when it cools down at night your bikes runs different or you rejet to keep the performance). I can get +3 extra timing advance with AvGas too, putting it almost to the same level advanced as alcohol. Hes been running his motors like that since 87 I believe is when he told me he started using AvGas.

 

I'm going to have to go with Pete on this one. My engine was a while back ported and the head was milled for more compression (BY Harry Klemm at Group K, Klemm Research) As you may already know, They do not work on ATV engines anymore. Even so, when I bought this motor in January, the owner told me to run Race gas, no matter what. Well, even though Harry Klemm isn't in the ATV business anymore, I gave him a call at his PWC shop, and well, he recomends AV gas. If high compression engines are a problem, the 50 gallons of AV GAS that I have ran through this motor must have been a miracle. For the price, and performance, AV gas can't be beat. Running it on a stock engine would be pointless. It has a high octane rating, and the lead works as a lubricant. I'll never go back to 6 dollars a gallon race gas, I'll stick to my 2.50 a gallon 100LL. Like Pete said, If another fuel is going to be ran, it WILL be crazy gas. (Methanol)

 

I'll also go with Pete and CJ on this one, I rode both of their bikes and the AV gas works just fine. Although you may get slighlty better performance with Race gas, it isn't worth the extra money.

 

I'm not going to touch the fuel issue!

As far as your other problem,I would venture to guess that you have developed an air leak on that side when you installed the new parts. Possible areas to check are: each side of the reed spacers and read cage (to be sure you have completely sealed this area it helps to apply a very thin layer of yamabond 4); hose clamp before the carb; carburetor cap; choke cable entry into carb (if it was removed recently); and boost bottle inlet.

 

hey,

now you got me interested in all this.

right now my banshee is at stock timing and compression.

i was going to get it +4 advanced and about the head milled so it would be about 20cc domes. actually i have a head i bought that is milled already but it seems sketchy so im going to sell it and get my stock head done.

but now that i see you can run higher compression/timing with av gas, well do you think i can run +8 with the vetos key and get my head milled so im at about 18 or 19cc domes and safely run it on av with no detonation? also if you know about milling banshee heads, do you mill it by the thousanths? and what if i got it 50 thousanths, woudl that be written as .50 or .050? i may sound alittle slow but im doing it all out of concern idont want to mess up my motor!

thanks for all the great info.

 

forgot to ask you guys,

what is stronger, alcohol or methanol?

and av gas you say is 2.50/gal? thats not bad...