explain the sprocket differences to me please?

[J.J.]

i'm about to place an order for some items and was thinkin of going ahead and picking up some sprockets while i'm at it..

on my 07 400, what is the teeth configuration for front and rear from the factory?

should i go down or up on teeth? i love my bottom end that it has now, but top end kind of lacks..

i pretty much ride trails though and a recreation MX track.. nothing crazy..

what sprockets would you guys recommend?

[katch26]

14-39 - 05+
15/38 - 99-04

not 100% on the years but I know the 07 is 14/39 and my 03 is 15/38. Going with a larger front sprocket or smaller rear will increase your top end. The front sprocket is easier to change than the rear and will yield bigger results. Going to a 15 front would be roughly the equivalent of going down 3 in the back. Its going to be a trade off though youll have to give a little to get a little.

[hypersnyper6947]

You will be sacrificing your bottom end by adding more top end to the bike. Yes the front sproket is much easier and cheaper to change but you cannot fine tune with it, like katch26 said ever 1 tooth on the front is like 3 in the rear. I suggest buying a 1 or 2 tooth smaller sproket for the rear. The less you change ( 1 tooth) the less your bottom end will suffer. I dont know about you but i prefer to have bottom end power over top speed any day.

My .02

[Snipe]

I agree but you have to admit that the 400ex has so much bottom end that changing the gearing in the ex to be higher speed helps in trails while not loosing much bottom.