I want to get a Front sprocket for my KFX but I'm not sure how many teeth to get. Can you tell me how many teeth is the best upgrade for the KFX 400.

 

what for???? i went 1 tooth down( 13 i think) on the front . gives you more torque on bottom end ,but you lose a little on top. how often do you have it wide open anyways. great for trail riding!!!!
you also have to look what kind of tires you are running. goinjg from a 20 in. to a 18 in. will change you gearing. i forgot how but im sure somebody can help with that answer.
i also went down 1 because i ride on sand with paddles and the sand likes to eat some hp! so i went 1 tooth down because i start in 2nd gear(drag racing)

 

Yeah mines stock I race but just with my friends who basicly just have some 400 EXs and stock Raptor 660Rs we drag and some circler tracks but thats about it mostly trail ride. I want speed but I dont wanna lose hp either.

 

I got stock tires on it.

 

I would rather gain speed than lose hp thou.

 

Ok it's basically like this. If you drop a tooth on you front sprocket you'll have a faster take off and acceleration, but you'll lose a few mpr on top end. In other words you'll get to your top speed quicker but it will be a few mpr slower. On the other hand if you raise the front sprocket a tooth you'll have a slower acceleration but you'll gain a few mpr on top end. Lower tooth = quicker acceleration slower top speed. Higher tooth= slower acceleration higher top speed. From your earlier posts I'd recomend dropping 1 tooth on the front sprocket.