VP Racing Fuels C12 - what do I need to know?

Hello all,

Well my persistent "knock" remains on my 2011 300 Race Gas Gas.... I tried 93 octane with some amsoil octane booster but it didn't seem to be any better than the 91 (with booster) that I started with. I used to run 91 with octance boost in my "regular" 2009 280. I have never heard knock before but I am pretty sure that is what I am hearing (and had a few people "in the know" listen to it to confirm my suspicion.

SO..... today I bought a 5 gallon can of VP-C12, and I think what I will try first is a 50/50 mix with the aforementioned 91. I do have a few questions:

What might the shelf life of the straight fuel be? I assume I can keep the unused portion for the rest of the season (10 gallons will last me quite a while). Is the metal can the best storage container?

Shelf life of "mixed" oil/race fuel/pump gas? Can I store it in my plastic jerry cans?

The can says "drain carburetor after each use" - will my mix be ok to leave in the float bowl between rides (usually 2 times a week, sometimes less, sometimes more)?

Any other precautions that I should be aware of?

Thanks!!!! as always.

Hello all,

Well my persistent "knock" remains on my 2011 300 Race Gas Gas.... I tried 93 octane with some amsoil octane booster but it didn't seem to be any better than the 91 (with booster) that I started with. I used to run 91 with octance boost in my "regular" 2009 280. I have never heard knock before but I am pretty sure that is what I am hearing (and had a few people "in the know" listen to it to confirm my suspicion.

SO..... today I bought a 5 gallon can of VP-C12, and I think what I will try first is a 50/50 mix with the aforementioned 91. I do have a few questions:

What might the shelf life of the straight fuel be? I assume I can keep the unused portion for the rest of the season (10 gallons will last me quite a while). Is the metal can the best storage container?

Shelf life of "mixed" oil/race fuel/pump gas? Can I store it in my plastic jerry cans?

The can says "drain carburetor after each use" - will my mix be ok to leave in the float bowl between rides (usually 2 times a week, sometimes less, sometimes more)?

Any other precautions that I should be aware of?

Thanks!!!! as always.

ALOT of things can cause knocking...

  • un-oiled air filter
  • lean jetting
  • wrong fuel/oil mixture
  • aftermarket pipes that don't sync the return waves with the cylinder correctly (porting principals of a two-stroke)
  • and commonly air leaks in the intake system (ex. when airbox isn't re-installed with a complete seal.

I advise taking a look at everything besides the pipe first. Unless it's a pipe similar to the SST with a VERY restrictive stinger cone that creates "pinging"

Best way to store it is in the metal can.

50/50 should work well.

Shelf life will be 3-4 months easy.

No need to drain the float bowl between rides unless its for extended time - like a month or so. The ethanol in the pump gas is what causes the problems. (no ethanol in c12)

You can run slightly leaner jetting with c12 than with pump gas. (specific gravity is higher)

I use C-12 myself and for the 290 evo I mix 3:1 with super unleaded, but I only make 5 gallons at a time, keep 5 gallons of pure in a metal can and leave the remainder of C-12 in the 30 gal. barrel. When it gets low I'll transfer it to a couple 5 gal. cans. I try not to open on humid days and have had excellent luck with storage up to a year.

Best way to store it is in the metal can.

50/50 should work well.

Shelf life will be 3-4 months easy.

No need to drain the float bowl between rides unless its for extended time - like a month or so. The ethanol in the pump gas is what causes the problems. (no ethanol in c12)

You can run slightly leaner jetting with c12 than with pump gas. (specific gravity is higher)

Yep thats what I do 50/50 with 91 pump gas,I actually called a tech up at VP and he told me the shelf life can be 6-12 months if you keep it in the can and in cool storage in the garage,12 months is probably a long shot,but if you ride fairly often it will be gone way before that.I just mix a gallon at a time 2 gal max and let the VP in the garage.he did tell me something along the lines that when you mix with pump gas shelf life goes down,so don't mix too much and don't leave your fuel in the sun if you can avoid it.I run the fuel out of my carb when done riding,do'nt really know if it's necessary,but psychologically makes me feel better.My 315r seems to run pretty good with this mixture I also use Elf 2 st oil 70:1.

I've used C-12 but at 25% with premium pump in 4Ts. I only buy 1 gallon at a time so it get used fairly quick, I also store it in a metal can. 1:3 with premium provides 100+ octane which solve most problems. Oh, it sure smells good to those following.:thumbsup:

Ethanol creates problems with pre mix and it is becoming more difficult to find gas without ethanol lately; here is a link to finding ethanol free gas: Pure Gas

Thanks everyone, for the replies and advice. All my questions are answered, and the 300 is running GREAT!

I mixed 40/60 premium/race fuel and it seems to work so I may even try a slightly weaker mix, but so far so good.

Although, after I drained the tank and carb and put in my fresh mix I "flushed" the carb by leaving the drain open and opening the petcock for a few seconds. But of course I left the petcock closed and the bike started to knock again and I though "oh no" but it was easily fixed :thumbsup:

Jon

if u mix for around 100 octane it should work well enough

Thanks everyone, for the replies and advice. All my questions are answered, and the 300 is running GREAT!

I mixed 40/60 premium/race fuel and it seems to work so I may even try a slightly weaker mix, but so far so good.

Although, after I drained the tank and carb and put in my fresh mix I "flushed" the carb by leaving the drain open and opening the petcock for a few seconds. But of course I left the petcock closed and the bike started to knock again and I though "oh no" but it was easily fixed :thumbsup:

Jon

Thats the best way to do it - back off the race gas as above - but for the final ratio - leave some margin for those really hot humid days.

If your problem is not common in other GG maybe check the ignition timing.

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