i had that problem its all down to floating in and out of the powerband causing you to grip harder causing arm pump up when cornering keep the revs really high and splip the clutch in and out a few times keeping the bike in the powerband and relax don't hold the bars too tight, you need to have slight grip but enough to hold on?
It takes a bit of time getting used to clutch slipping i pitched loads of times,causing the bike to wheelie were i wasn't pumping the clutch i was off or on this caused massive wheelies and you no on dirt no smooth surface FUCK off the back? but thats my opinion i ain't teaching you to suck eggs it worked for me and a lot of my mx buddies once you get it you'll tear those 4 stroke s apart round the bends and on the straights yeeehaaa
![headbang :headbang:](http://forum.zx10r.co.uk/Smileys/default/headbang.gif)