MY cousin has a 99 400ex and his buddy has a 2000 400ex the 99 has some mods like a K&N filter jet kit,holshots modified stock exaust. the 2000 400ex smokes all him time is this a weight differnce in the riders or what I rode the 2000 and I rode the 99 when it was stock the 2000 fells like it has better throttle response and a little more top end speed. welll remember ride red ride smart and ride hard!!!!!!!!!!

 

I think the 2000 is faster than the 99 due to the bold new graphics. With the inspiration provided by the racy new graphics riders reach a higher level of performance.

Seriously now, there is a difference. The stock main jet on '99 is a 148 while on the 2000 it is 158. Also, I think the internal design of the stock silencer is a little different.

There may be other differences but these are the only ones I have heard.

 

I think honda did something there not saying besides bold new graphic's maybe a slightly milder cam. I don't knoe like I said the 2000 feels s lot better than the 99 I don't like either of them's egro's though and I prefer 2 stroke power more than 4 stroke. I like my 250r better than them both.

 

my 2000 had a 148 and i changed it to a 150.

 

I own a 99 400EX and a friend rides a 2000 400EX. We both put on a K & N jet kit. We both had stock 148 mains. I take him off the line and through 3rd gear, then for some reason he pulls me on top end. But, overall, pretty close.

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