Reasonable priced, consistant fuel, without alcohol?

[SpDyKen]

I'm looking for fuel options.

I've been running 25% VP C12 with 75% unleaded premium 93 pump fuel in my stock '06 YZ125. Switching now to my '06 250. But now, after taking some time off to repair my rotator cuff, it is not possible to find any premium pump fuel without alcohol.

I have learned, from reading Rich's posts here, that I should not be running pump fuel, anyway.

So, with the Perry Mt. 24-hour Challenge coming up, I need to find a reasonable fuel alternative. Anyone have any suggestions?

I'll be running our YZ250 pretty much stock, engine-wise. I will be modifying the cylinder head to reduce the excessive squish clearance, but maintaining the stock combustion chamber volume. I am about to test a FMF Gnarly pipe this week, but the bike already has plenty of power for us, as I'm getting the jetting dialed in. If I had some more time, I'd probably send the cylinder off to Eric to get a bit more bottom, but this too is getting better with jetting.

I estimate that we will be burning about 2.0 to 2.5 gallons per hour, (maybe a bit less.)

Thanks for any ideas!

Ken W.,
Team I.O.W.A.

 

[Rich Rohrich]

100 LL Avgas cut with C12 is a decent alternative.

 

[SpDyKen]

Thanks, Rich, for your advise.

I had thought about that, given the consistancy and availability of the 100 LL Avgas, but also knew that it wasn't an ideal fuel, either, thanks to the information you have posted previously.

I suppose the decision regarding the ratio could be budget influenced. I'd go at least 1/4 to 2/5 th's probably, at a minimum. What are your thoughts on this, Rich?

Unrelated, but I am planning on running Yamalube R at 32:1.

Thanks again for your help, Rich. :cool:

 

[Rich Rohrich]

How hard will you be running the bike? Lots of low speed part throttle stuff, or more wide open high rpm running?

 

[SpDyKen]

Lots of low speed part throttle stuff.

I'm riding it mostly just off idle out of turns in the woods here, to maintain traction. (I have the 8 oz. Yamaha GYTR flywheel now. The E-line stator is suppose to be more like 11 oz.)

Probably 90% to 95% of the 11 to 13 mile lap will be slow to medium single track, with occasional short bursts down fire-roads, or other quick bursts of speed. Last year there was a couple of longer fire road sections, with a last section of switchbacks through some pastures, right before coming into the pit area. Not too much 5th gear stuff, and probably only the pasture sections will see the rev's into the upper range in 5th, and even then, not for very long. The half-lap of an old-school MX track will be one of the easiest sections.

Overall, mostly tight, technical trails with lots of terrain & elevation changes, woods, rocks, roots, silt beds, ruts, and various soil types. The trail gets pretty chewed up after 24 hours with 150+ bikes. They'll re-route some, and shorten the course, as the race progresses. Virtually no long, straight, WFO speed sections. I don't think I'll need to swap for the WR 426 tranny gears.

Fast, pro-level riders will be under 30 min. laps. Average for me will be closer to 40-45 min. The course changes every year.

My goal is to make the bike easy to ride, with a wide spread of power. I rode this morning, and I'm still leaning the pilot circuit; 45 still rich, even in the cool morning air. I have not touched anything else yet. I'll get some AVGas tonight to mix up for tomorrow. I still have 4 gal. of C-12 left. I have to check and compare the elevation we'll be riding at in Alabama.

Again, Rich, I appreciate your input and advice! :boss: Thank you very much. :cool: :ride:

 

[Rich Rohrich]

Ken - If it's mostly part throttle stuff then it's best to stay with the highest percentage of C12 that you can afford. The type of riding you'll be doing is exactly the application that AvGas tends to show it's warts. Throttle response and ease of tuning will be improved with more C12 in the mix.

If it were a desert race then high percentages of AvGas would be a good alternative.

 

[SpDyKen]

Thanks, Rich. You confirmed what I had been theorizing.

I was hoping to find some other option, but had not found one myself.

At least I'll not be wondering what I'm pouring in the bike!