my 05 kfx400 is slow

[Studster]

i have a kfx 400 with full yoshi, mod quad airbox with k&n filter, jetted, white brothers rev box 13/40 gearing and i cant even come close to a stock 400ex with a hmf slip on as far as power or speed... i thought these quads were suppose to be faster but i guess not... anyone have any suggestions

[knoxville9]

Put a 14 tooth front sprocket on for sure a 13 is useless ive riden everywhere with a 14 never need a 13 if you can ride it, if you wana spend money put kibblewhite valves and springs and a high comp you'll know a difference trust me I never got beat I even kept up with a yfz473

[shiley55]

The guy on the ex must be a beast.

[Studster]

took the air box cover off and its like riding a total different quad... made a world of difference in power... runs exact even with the ex now

[KFXFreak]

Still something is wrong. You should be beating that honda pretty badly even if you were stock. Something is out of whack. My stock motor kfx400 would laugh at a bolt on 400ex.

[Studster]

low psi on a compression test... time for a tune up i suppose

[KFXFreak]

Low PSI could be a couple things. If a valve is not sealing that you will lose compression big time. If you got it down that far check the head real good.