i just read the review of the 2k1 400ex at atving.com...... they said the ex is happier when u short shift it.... i know what short shift means but what exactly were they trying to say.... does it hurt the engine not to short shift it cause when i ride with all my buddies one their 400exs they get the most out of each gear and i do just about the same... i occasionly short shift but only when im going through sound sensitive areas.... just curious though

BLC,
On most four strokes, short shifting tends to be a more efficient method of delivering the usable power to the wheels as opposed to winding the engine out to the rev limit as is the practice with 2 strokes. On the vast majority of 4 strokes, the peak power output occurs at a point fairly well before peak RPMs. One possible exception to the rule is the Raptor which as I understand, revs to 9k. If you were to put your ride on a dynamometer,you would see the point where your HP actually begins to drop off even tho you are not at full throttle. Winding past that rpm point is counter-productive, hence the need to short shift. Only experimentation will tell you where that point is but when it is discovered your friends who are winding out their 400exes to max throttle will get used to seeing your rear shock thru the dust:)

BLC,
If you ever look at a power curve on a 4-stroke, you will notice that peak torque is far below max HP in relation to RPM's. As the torque begins to drop off, HP is still raising. HP is just a measure of how fast an engine will do any given task(RPM's). Since the volumetric effiency of an engine is greater at lower RPM,s, that is where the most twisting power is(torque). If your putting HP to the ground, your either going fast, or your spinning your tires. If your putting torque to the ground your hooking up and getting max traction.

Rick