boging in the top end?

[quader400]

well does any one know why it could be boging in the top end? its my freinds 400. he is getting a vavle readjustment would that fix it . does anyone have any ideas thanks for any help.

Sounds like his main jet is too big...:macho

[quader400]

its stock with kand n and no air box mods

[cals400ex]

with a k and n filter i would try a 150 main jet. also, the valves is probally my problem. i was getting my *** smoked by my friends in the higher gears and it turned out that i just needed the valves adjusted. runs great now.

[*FoX*KiD*]

you might have a whole bunch of dirt and carp on your air fliter try useing the K&N recharger kit

[F-16Guy]

That bike is way lean in stock form anyway, and the K&N probably ain't helpin'. Go up a couple sizes on the main, and go to a 40 pilot.