300ex low-mid rpm hesitation

[punker69q]

When I put the throttle all the way, my quad allways hesitate? what can be the causes of that?

[dirtclog]

not enough info really but here's a couple ideas...

If machine can be "rolled" into the throttle ok may need valve adjustments

could be clogged jet(s)

could be clogged fuel line

could be clogged exhaust (carbon buildup)

air filter clean?

[Rastus]

look for proper jetting, nad make sure the carb and gas lines are clean.If this doesnt help, it might need the valaves adjusted.
So, pretty much what dirtclog said :)
Id check the easier stuff first, if that doesnt help, thats when id try adjusting the valves