i just bought an 04 yfz450. i took it to a pit and and when i got to the top of the rpm's it bogs out. i tried a new spark plug, gas etc. when i bought it, it didnt come with a baffle. could that be why? also when i ride it threw semi deep puddles it kind of spudders, is something wrong with the electrical wires?  

if it isw bogging down on top end then the fuel mixture is too rich. try adjusting the fuel/air mixture screw to the right in 1/4 turn increments to lean it out.

sputtering when hitting puddles is normally a sign that you are getting water in the air box.  try using some sealer on the air box cover.