Rec Fuel vs. Pump gas?

Scoob

Scoob

PR Founding Father
OK, need some info here from the peanut gallery to help my thick skull with this one. My thoughts...

90 Octane Ethanol free gas would be a "better" gas as it is "pure", more consistent, last longer, yada, yada. Pump gas, having ethanol, contains small amounts of water being made from corn, is inconsistent, would be harder to jet for consistently (for us still using carbureted moto bikes), yada, yada.

In what all I am being told, pump gas is what I should be using in our Cobra. Is what it was designed for. Just find a gas station that sells a lot of gas, buy it in small amounts as needed, and all is good? I am just stumped. Sure, I could go the C50 route, but not an option. I may go ahead and cause myself some more heartache and play around with some jetting, but in what my peers are working with, their Cobra's run pretty damn good on 93 or even 87 pump gas. Looks like that's where I am headed...

Thoughts?
 
Rec caused late detonation in our cobra Jr. I probably could have jetted it differently, but I went back to pump.
I then switched to av gas. It has been great for us. Have ran it for the past few years. It doesn't load up, it doesn't go bad, it is consistent and can be stored in regular plastic gas jugs. The c50 smells great, but the biggest thing it provides is not loading the bike up on the starting line. You probably get a slight performance advantage it your kid is 110% on the gas. I just don't think the juice is worth the squeeze, when I have av gas closer to me then pump gas, or trying to track down c50
 
Thanks man. We have a small airport close to us, but last I called them a year or so ago, they stopped selling it to the public as I planned to go that route for all my bikes at the time. Good info and is consistent with what I have been told about rec gas. Rob was telling that pump gas just burns better than rec fuel and that made sense to me as well. Not sure why I have to be so bull headed and just not beleive everyone...lol.

Might be pump gas for now...laters.
 
Actually had already bought a 50 slide, 260 atomizer, W9 needle, and had a 50 pilot. I put those in to try. Totally my ticket for now with 90 octane ethanol free for the winter. Had fuel screw out 3 whole turns when it was warmer. Had to screw it back in a turn when the temp dropped Friday going into Saturday. I am happy for now. :)
 
Last edited:
I ran 93 octane forever with no issues. Currently I run 90 rec 50/50 mix with Sunoco 110 race fuel since we now have modified bikes.
 
i always ran pump gas 93 my whole life, and then started running 50/50 cam2 and ethanol free 90.. my exhaust was really light grey almost white, made it seem like it was really lean. it stayed that way and never seemed to clear up. kind of nervous to run that combo again, figuring that couldn't be a good sign and it wasnt like that until I switched.

thoughts? its convenient because I have chardon oil 5 minutes away that has the cam2 at the pump. i think they stock VP too though, so maybe I should look into that or finding sunoco fuel...
 
TwentyThreeMX said:
i always ran pump gas 93 my whole life, and then started running 50/50 cam2 and ethanol free 90.. my exhaust was really light grey almost white, made it seem like it was really lean. it stayed that way and never seemed to clear up. kind of nervous to run that combo again, figuring that couldn't be a good sign and it wasnt like that until I switched.

thoughts? its convenient because I have chardon oil 5 minutes away that has the cam2 at the pump. i think they stock VP too though, so maybe I should look into that or finding sunoco fuel...
Click to expand...

cam2 (or any leaded fuels) leave behind the white residue.. nothing to do with a/f ratio. changing fuel alone really shouldn't change your a/f ratio, the bike is still going to inject the same amount of fuel unless you tell it to do otherwise.

there is no reason to run race fuel on a stock engine imo. a benefit one could potentially argue is that it won't go bad as quickly as pump gas does. i've had the same tank of 110 in my drag car for like 150 years now.
 
Bill480 said:
cam2 (or any leaded fuels) leave behind the white residue.. nothing to do with a/f ratio. changing fuel alone really shouldn't change your a/f ratio, the bike is still going to inject the same amount of fuel unless you tell it to do otherwise.

there is no reason to run race fuel on a stock engine imo. a benefit one could potentially argue is that it won't go bad as quickly as pump gas does. i've had the same tank of 110 in my drag car for like 150 years now.
Click to expand...

buy another dirt bike. k bye
 
Ethanol Free is richer. No corn or water like residue in it. Carb bike you'll need to lean it out a tad. FI I'd figure would do that for you.
 
Last edited:
For years as a kid we ran av gas when we went racing (We would ride to the airport through the corn field with our oil bottle on our lap lol)
Then we would run high test pump gas when practicing with no issues whatsoever with either... Now who knows how close I was on jetting back then but I rarely had any motor issues with my old 2-Strokes and I raced and rode the heck out of them on the east coast.

In my 2001 Yamaha 426 it ran better on race gas and started ok when cold but was almost impossible to start when it was hot on race fuel. On pump it started perfect cold or hot. I think pump gas w 50% race or Av gas was the way to go for more octane for most 2-Stroke bikes back in the day. Race gas run's cooler overall as pump gas runs hotter for from what I have seen. Also pump does not prevent detonation like race gas.

These days I run straight race or 50/50 race gas only... If I understand it right av gas is made for low compression motors (planes) and not have as much advantage as race gas like VP C-12... It's expensive but works really well. Or a cheaper option is Sunoco 260 but it's not as good as VP products in my opinion.
100% now in my 4-Strokes I run strictly pump gas as they do not need as much oxygen as my 2-Stroke. U4.4 is jam if you have tons of compression however.
Really too much to think about for most people but if you want it running great and for awhile you gotta do something....

Waaay more info than you wanted I am sure.

-Fast50s
 
You must log in or register to reply here.
Back
Top