Race Fuels

Hey I just got off the phone with VP Race Fuels and was getting the scoop on which fuel to run in the 426. They are telling me the "Motorsports 103 Unleaded" is the stuff that I want. They said they have been working with yamaha and this is the best stuff to run in the bike. If this is not available then they said the Performance Leaded C-12 would be the next choice. Now I know nothing about fuels. I wanted to try a different gas because my bike is running a little rich and don't feel like messing with jetting unless I absolutely have to. I have bad luck when I start messing with things that are running fine. The folks at VP said the bike will run leaner with this fuel. Unfortunetly it souds like a pain in the butt to get. I live here in Corona, CA. and there is only one place to get the 103 they said. I'll get back to you all once I get some and try it, and tell you what the diff. is.



I’ve run into the same situation with my 01 426. In the second moto on Sunday my bike had the symptoms of running rich off the bottom. It’s been running great for the past couple of months after I went through the painstaking process of jetting my bike to match a DSP pipe. The bottom end bog only started after I went through a full tank of pump 91-octane gas here in California. I started it again last night and it ran fine for the first five minutes and then it started acting rich again.

I’m also considering running a 50/50 mixture of race and pump gas since I don’t want to screw with the jetting again. I’ve been checking around and it looks like I’ll have to buy a five-gallon metal can of race gas. I only get to ride on the weekends so the five gallons of race gas, or ten gallons of the mix, will probably last me a month. What’s the best way to store the fuel? One alternative is to mix the ten gallons and store it in plastic gas cans, the other is to leave the race fuel in its metal container and mix as needed. I could also store the race fuel in a plastic can if that's better.

I don't know anything about the 103 but I've used the C-12 a lot. It runs much richer than pump fuel. You'll need to lean your jetting to compensate. I run C-14 in my 450 and it LOVES that stuff (but $6.20 a gallon can hurt). C-12 is pretty common as far as VP fuels go.


MX Tuner

Although I havent done it(going to this weekend), the BK mod may get rid of that richness on bottom.

I have been running a mix of the VP 108 octane (I don't remember the designation) and pump 92 (1:1 mix) and combined with the BK carb mod the bike is AWESOME!

I have the Yosh pipe and bought an 02 CR 250.

I took both bikes to the track Sunday just in Case I wasn't ready to ride the 250.

I rode the 250 2 laps in practice and put it in the trailer and got my 426 out.

Since I forgot to get gas for the 426 I had to use some VP-MR2, which is what my kid runs in his CR 125. I tried it and was amazed at how good the bike ran.


Hey guys I went to the track today with the VP C-12, which is the 108 octane, The bike definately leaned out. I had removed my old spark plug which was black and sooty and replaced it with a fresh one. After a couple hours on the track I came back and WOW! what a difference in color. The plug was white with a little tiny shade of brown. I think this is good? (Someone let me know. I RTFM and I think it is.)But I have read on here that white is too lean. This gas really brought out the poor zero to 1/4 throttle repsponse I guess I will do the BK mod to try and fix this.

Hey for those of you that care Fonseca was out here on his new CR250 tearin the track up and looking good.


Chiledog! :)

Hey check it out I am finally a Member I dropped that JR. status. I guess runnin my mouth gets me some things. :)

To answer one of your original questions, keep the race gas in its metal container and mix in plastic as needed. The plastic containers allow the really light volatile chemicals to seep through it and your gas ends up getting heavier and will get your carb all nasty. I use pump gas only (our only local guy with race gas price gouges) and my rule of thumb is 1 month in the garage, older than that and I dump it in my truck and get some fresh stuff.

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