i have i 99 400ex that is stock and i feel that the first gear is too high and would also like to increase acceleration and my wheeling ability. I heard people talking about installing the 14 tooth sprocket on the front. i was wondering how much to end is lost and if it helps much on acceleration and power. im not to concerned with top speed since i ride in the woods and on the track some.

 

Go for it! Expect greatly improved power/acceleration with only minor top-end loss.

 

400ex calculator

Hit the link above and input some numbers to tell you what you get a general feel for what you will lose from a straight gearing standpoint.

This chart doesn't account for all factors such as the hp lost from running a smaller set of sprockets versus a larger set for a given sprocket ratio. For example 15/30 and 16/32 are the same mathematically from a ratio standpoint yet the 16/32 will result in more hp hitting the back tires (albeit it is not noticeable from a seat of the pants test).

/NotuRaptor