View Full Version : Big bore tri-z should i run av gas 40:1 ams??
MOTOMAX27
11-25-2010, 04:42 PM
Hello. Happy Thanksgiving!! just want to get some info i would run c12 with40:1 ams oil. but its way to much$$ 65.00 for 5gals. just checked up av gas 100ll for 5.99 a gal and its super close for me to get. should i run straight av gas with 40:1 ams?? iam not sure but last time a tryed running 93oct it would knock but its been some time. Hope everyone is doing good. thanks max
4cfed
11-25-2010, 06:52 PM
personnaly id stay away from the amzoil... klotz techniplate is nicer, and try mising the 100ll 2 gallons to 1 gallon premium and see what happens, your compression that high it requires high octane fuel??
or check into vp fuels they have aline just for atvs and dirt bikes
Tecate 50
11-25-2010, 07:56 PM
I ran straight VP C-12 in my Tecate. It didn't quite burn effectively for me so I switched over to VP 110. That being said....my Tecate has 180 psi. I didn't have any problems with straight VP 110, but I started mixing 2 1/2 gallons of the 110 and 2 1/2 gallons of 93 octane gas out of the pump. Seems to be the best ticket for me, and its saves you tons on money. C-12 at the time was about 12.00 bucks a gallon at the time and the 110 was about 6.00 bucks a gallon. Remember the burn rate of the higher octane is slower. Check the compression of your engine...that will give you a ball park figure on where you are at. In my personal opinion C-12 isn't needed for the 2 stroke application. I have discovered that 2 strokes like to be around 100 to 104 octane. Anything higher blows right out of the pipe unburned, and at times like mine did crusted up on top ofthe piston. That was a real mess that happened when running straight C-12. Every motor is different.....so I would start out with the VP 110 at 6.00 bucks a gallon and mix it half with pumped gas. I haven't had any detonation problems and in my opinion runs just as strong. When you get up past 180 psi....I would run straight VP 110 anything lower I believe you can cut it half and half!
MOTOMAX27
11-26-2010, 01:58 AM
i was running vp staight. to much and hard to find. i have a airport near by that sell av gas.
bigbadktm
11-26-2010, 06:41 PM
there were some cons to running av gas, but I'm not sure if they were a myth or not. i used to run 40:1 with 91 and 110 mixed 50/50, not sure how much it helped but my bike sure like it, now the bike is just set up to run on 91, may add some octane boost but it seems to run great as is.
Tecate 50
11-26-2010, 06:48 PM
Aviation fuel doesn't have any lead content VP 110 does.....high octane with no lead= high temps! I prefer having lead in fuel for added security!
3Razors
11-27-2010, 01:08 AM
Avgas 100LL the blue stuff is leaded, quite high actually. Its around $4 a gallon here which is only 1 dollar more than pump premium. Its federally regulated by the gov so it's about the most consistant around which means its the same stuff whether you buy it in az or new york. I've run it for 15 years, give it a try you'll like it.
cr480r
11-27-2010, 05:03 AM
run av gas..
MOTOMAX27
11-27-2010, 11:00 AM
should i run it richer or leaner??
tecat-z
11-27-2010, 12:59 PM
Hmm, this has my interest. I usually run leaded fuel in all my 2strokes for the protection factor, and the fact that my motors really seem to run smoother. For those in the know. What does the AV fuel compare to? For example in a comparison to a particular VP fuel blend. Are there different types of AV fuels, or simply one blend that is universally blended by one or more manufacturers. Please give an accurate description of AV fuel content if this info is known. Thanks guys.......
MOTOMAX27
11-27-2010, 01:26 PM
wonder if any guys that have bb kits on there Z are running avgas. today i will check compression and try avgas. will post updates later. thanks
MOTOMAX27
11-27-2010, 03:44 PM
190psi still has a knock. think iam changing dome. dont even know what cc it is. update in a few. also iam have 175main and 52polit tryed with 1-1/2 aie screww out and pulled it out to 2. and still knock. avgas straight with 40:1 amsoil. I will be back..
3Razors
11-27-2010, 04:48 PM
Hmm, this has my interest. I usually run leaded fuel in all my 2strokes for the protection factor, and the fact that my motors really seem to run smoother. For those in the know. What does the AV fuel compare to? For example in a comparison to a particular VP fuel blend. Are there different types of AV fuels, or simply one blend that is universally blended by one or more manufacturers. Please give an accurate description of AV fuel content if this info is known. Thanks guys.......
The one you'll most likely find and everyone uses is 100LL it has a blue tint to it. It usually tests out in the 105 octane range, closest I think it would compare to is vp red since its leaded and non oxygenated. You'll hear all kinds of stories and myths on avgas and there bogus, mostly the race gas shops that start this because they want your money. Now, that being said certain built to the nuts motors do require full race gas. But the way I look at it is I can get 95% of the benefits of race gas at half the cost by using av. Interesting fact is that boyesen use avgas when they do all there testing on reeds.
MOTOMAX27
11-27-2010, 05:44 PM
now i have 210psi and still knocks when i hit the gas. but reponse is better with this dome. i cant think of anything esle to do.
Tecate 50
11-27-2010, 06:32 PM
The one you'll most likely find and everyone uses is 100LL it has a blue tint to it. It usually tests out in the 105 octane range, closest I think it would compare to is vp red since its leaded and non oxygenated. You'll hear all kinds of stories and myths on avgas and there bogus, mostly the race gas shops that start this because they want your money. Now, that being said certain built to the nuts motors do require full race gas. But the way I look at it is I can get 95% of the benefits of race gas at half the cost by using av. Interesting fact is that boyesen use avgas when they do all there testing on reeds.
Thats some good info right there.....I was unaware! Gonna have to look at our local availability and prices for that stuff! I do know the VP Red is real pricy......thanks.
cr480r
11-27-2010, 08:10 PM
if its easily accessable in your area its a great alternative to watering down race gas with pump junk... it may not be race gas, but its perfect for bikes that dont need 110.. my tecate cranks 245psi ran great on av gas.. My suzuki before that was cranking 215psi with a 190* duration.. never a detonation related problem with either... I had a detonation prone CR500.. it loved the av gas too.. I eventually started using race fuel only because my airport tightened up on its security. I would like to add that av gas also seems to store better than race gas in my opinion.
3Razors
11-27-2010, 08:23 PM
now i have 210psi and still knocks when i hit the gas. but reponse is better with this dome. i cant think of anything esle to do.
Maybe check timing? I'd make sure its set at stock to take away a variable.
cr480r
11-27-2010, 08:30 PM
jetting may be a variable as well.. lean on the needle circuit can cause a knock that will go away on the main circuit
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