Gas Question =vp-u4 [3 Hpgain] Jetting And Temp

I Bought Some Vp U4 Gas Because I Read In A Magazine About The Easy Hp Gain,but Than I Was Told Not To Run It Until It Cooled Down {its +100 Degreez} And I Might Need To Lean Out The Jetbut Thats A Maybe .so Has Any One Got Any Input On This I Am Determined To Get This Going It Is About A 3-4 Hp Gain From The Dyno Numbers Ive Seen From 2 Different Places

Isn't it a lot of work to capitalize every word??

Anyway, normally, U4 will require a larger main jet to work right. The pilot may also be too small, depending on your current setup. If you think it's about right now on pump gas, try one size larger, maybe two, on the main and see how that works.

There's no problem running it in hot weather that wouldn't exist in 80-90 degree weather. Be sure you drain the tank and carb after every ride day. It will turn on you if left in the fuel system.

Ditto to what GreyRacer has indicated...also never dilute it with any other gas - you must drain it after each use otherwise the vapor in the carb from left over fuel in the float bowl will cause a gummy brown build up....adding to your maintenance.

Isn't it a lot of work to capitalize every word??

Anyway, normally, U4 will require a larger main jet to work right. The pilot may also be too small, depending on your current setup. If you think it's about right now on pump gas, try one size larger, maybe two, on the main and see how that works.

There's no problem running it in hot weather that wouldn't exist in 80-90 degree weather. Be sure you drain the tank and carb after every ride day. It will turn on you if left in the fuel system.

He wrote in all caps, the system just changes them to all first letter capitalized though. I also agree with Gray on this one, but IMO just run regular premium unleaded.

i finally used the u4 gas and it is well worth it you will not be mad at all.give it a try ,it will work great in a stock bike with stock jetting. my bike is jetted to fmf specs and i used it and loved it. so as long as your not jetted to phat it will work great on low compression

"Low" compression? Stock is over 12:1. Generally, anything over 10:1 is "high", and requires premium. From 11.5:1 to 13.5:1 is "very high".

ok well i mean stock compression,and premium gas sucks ass 110 gas is great for high compression,110 gas will make a high compression engine run great ,but any ways the u4 gas works great on most 4 strokes all the pros run it

What Grey and GA426 said is very true about draining your fuel if using VP u4! It will gum up! It has to do with the addatives VP uses in this fuel. VP is the only race fuel that does this. The oxygenated fuel do require jetting up depending upon the oxy. content % weather or not you have rejetted for a pipe or not! I do know that Sunoco makes a fuel called m02x that is unleaded that will not require draining your system and is 2.7% oxygenated, this means youwill need to up your jetting 2.7%. Good luck!!

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now