vp ultimate 2 fuel in eric gorr ported cr250

[john stu]

i want to try the vp u2 fuel in my 2002 cr250 (ported and moded for race fuel by eric) but before purchasing some u2 fuel i just want to know if the u2 has enough octain for my motor set up for race fuel, i am running the c-12 right now and i know the u2 has less octane so i just want to be sure im not waisting my time and money on the u2 just to here my bike detenate.also how much richer should i expect to go on jetting ?or should i mix the ultimate 2 with the c-12?.one last thing does the ultimate 2 have a shorter storage life then the c-12 if so how long can i keep it in a metal can? do i need to buy it all the time in small amounts to keep it fresh? or is it ok to buy a 30 gal drum and keep it for a couple of months?


:think:

 

[murphy's law]

John, I have the same mods done to my bike and i recently bought another 5-gallon drum of U-2. I haven't had the chance to ride long term on the new motor but i can tell you that i did not make any jetting changes when i switched from c-12 to U2 with my stock motor and there was no problem with detonation. Now, with the increased compression and race fuel specific porting, I'm not so sure but i can't see there being that much of a difference. If you want to play it safe just go up one on the main jet from your C-12 setting. I think mixing C-12 with the U-2 would take away from the potential increase in power that you would get from running it straight up. This is what I'm running for jets right now for C-12.
380 main
76 needle in second pos
30 pilot
S-8 nozzle
2 1/2 turns a.s.
v- force m/t
eric gorr mo-better porting
fmf fatty pipe and silencer
motul 800t @ 32:1
I have started my bike and ran it on the stand with straigt U-2. ( it was too cold to take it out of the garage) I know that throttle respose was better and that the smell of U2 exhaust carried through my house like there was a 747 on the bike stand. Needless to say that I'm the only one that enjoyed it. Hopefully Eric or Rich will chime in with some more definative answers.

 

[Rich Rohrich]

i want to try the vp u2 fuel in my 2002 cr250 (ported and moded for race fuel by eric) but before purchasing some u2 fuel i just want to know if the u2 has enough octain for my motor set up for race fuel

VP U2 has an MON of 100.9 which is more than enough for this setup. :thumb: