hey i had a 440EX and it wouldnt work wirth crap even my brothers stock 400EX beat it people with this if you could tell me how good it works if something wasrong with mine or something?

 

i'd say something was wrong, mine work good.

 

Need way more information. All mods to both bikes (including jetting, gas used, which 440 kit, etc.......) Every detail.

 

something is way wrond.
maby you forgot to change the cilinder, but changed the cilinder head?

 

My 440 rolls ive beat a raptor with 686 kit and pipe a built YFZ the 450r and banshees but are you sure that who built your motor even did bore it?

 

My guess is to fast of a cam. A fast cam suucks in the woods.

 

Check to see how low your gearing is. Or check your spark plug. Because I go after yfz's and 450r's with my 440ex. Not stock 400's.

 

I have a 440ex as well with a JE 11.5 to1 piston and a stage 1 web cam.
Which cam do you have and what kind of race was it and how long?

 

well i was just asking i have allready sold it and got a raptor so now i only have my raptor and banshee

 

my 440 runs great but i use 110 octane, you could be using too low of an octane, if you didnt know you have to use a higer octane when you increase your compression ratio try using 100 or around there and see how that works, also how did it run before you had the kit put in and what other mods do you have