At the moment I'm learning the stand up wheelie and the way I do it is first I wheelie sitting then I just stand, now my problem is when I standup my right hand which is obviously on the throttle cant move any further (I cant give it more gas) so the bike comes down, what am I suppose to do?!

 

try coming off the seat when the wheel is coming up,its a much smoother feeling also place your hand further up on the throttle before u start this way when your up your hand is in a proper grip