PRE MIX RATIOS

[TD313]

     

I have an 03 CR 250 and have always run from 32 - 36 to 1 pre mix ratios. I was told by a person who I respect greatly to move from 93 no eth pump to ava gas and run 60 to 1. Woo, big change, his reasons are, the ava gas burns slower and cleaner than the pump 93o, ok I see that. He says the manfs. always tell you to run more oil than you really need to and to check the ratios some of the race teams (2 stroke) run which is closer to what he recommends. My side is this, race teams have a bigger budget than I do. Don't want to rebuild after every race. Would love to have your feed back on this.

Twang D

[Randog Leader]

I have not tried it, personally but from what I've heard and read, it doesn't make a big difference. I'm sure some others will chime in but you'd be better off buying race gas or something like KLOTZ that you can mix in with pump gas.

I would stick to 32:1 no matter what.

[PawPaw]

Run 32:1.....Don't use av gas for you stock compression engine as it burns way too slow and thus will have an effect on the jetting needed to make the engine run fairly well.
A well jetted stock compression engine will run better on 93 oct gas than it will on av gas.

Paw Paw

[Randog Leader]

True. Race teams don't have the same motor that you do. Spend more time setting the float height and getting the jetting "spot-on" and you will smoke the guys that run race gas with a poorly jetted machine.

[colorado_rider_450]

My old 88 cr250 has run klotz 40:1 it's whole life. I wouldn't go over that though. I have a buddy who was told to run 100:1 in his ktm 300 and, of course, burned it up.

[TD313]

Thanks guys, I worked on the jetting last year before our series, got it spot on after some trial and error. Didn't even think about the jetting with the av gas and stock comp. Bike runs great on 93 oct at 36 to 1. Like everyone says, if it ain't broke.......leave it ALONG!


Thanks again,

Darrell

[colorado_rider_450]

Originally Posted by PawPaw

Run 32:1.....Don't use av gas for you stock compression engine as it burns way too slow and thus will have an effect on the jetting needed to make the engine run fairly well.
A well jetted stock compression engine will run better on 93 oct gas than it will on av gas.

Paw Paw

Have you ever heard of anyone running avgas for added lubrication? I work at an airport and get a bit here and there for free so I always throw it in my car but was considering running it in my 250. It's 100 octane with lead.

[JMV]

I think you can run av gas without premix it lubricates so well!

[colorado_rider_450]

I think I'll take your word for it and not test that theory on my engine

---------- Post added at 09:33 PM ---------- Previous post was at 09:32 PM ----------

I'll throw it in my buddies ktm, he's already fried once, what's one more? HAHAHA

[schwen_108]

Do not use aviation gasoline, do NOT run a 60:1 premix ratio, you WILL blow up your top end. If you want a high quality oil go out and find yourself some Dumond Tech Z-1 TCW Injector/Premix oil. It is literally the best 2-stroke oil you can put in that machine. Run it 32:1 Just as Honda recommends, If you're fouling plugs or getting excessive spooge, than it's time to re-jet.

P.S. If you want your gas to burn better, go out and buy some 110 octane race fuel (VP, Sonoco) and mix it 50/50 with 92 octane pump gas.

[David_L6]

Originally Posted by colorado_rider_450

Have you ever heard of anyone running avgas for added lubrication? I work at an airport and get a bit here and there for free so I always throw it in my car but was considering running it in my 250. It's 100 octane with lead.

You're running leaded gas in your car? If so, I hope it is a pre catalytic converter car.

---------- Post added at 07:59 AM ---------- Previous post was at 07:54 AM ----------

There are a lot of opinions, old wives tales, and just pure bad information out there concerning running AV gas in something other than an airplane. Do a few searches using your favorite search engine(s) and see for yourself.

[colorado_rider_450]

Originally Posted by David_L6

You're running leaded gas in your car? If so, I hope it is a pre catalytic converter car.

Not pre cat converter, but highly modified with turbo and no more cat. It loves a 50/50 avgas and pump fuel mix. I am well aware of the problems leaded gas can cause in vehicles with too damn many sensors. I was just curious about running it in my bike since I know the lead lubricates and I can get it for free here and there. Not looking for a power gain, it's just free fuel.