KTM50cc Pro Senior

My son has a 2003 KTM50cc Pro Senior. It starts and warms up fine, the problem is that when you are at idle and hit the throttle hard it hesitates and seems to try and die. If you ease the throttle on or get it rev-ed first and hit it the bike runs great. I am sure it is in the jetting but I am not to great with jetting. Does any one have any suggestions on what I should try first. I was thinking I needed to move the clip up or down a notch on the needle.
The KTM is an automatic, chain driven, liquid cooled fire ball, having it hesittate and then hit is not good when you weigh fifty pounds.

Jetting is the solution. A combo of needle and main jet will get it cleared up.

You are describing a lean situtation. It needs more gas.

Of course, I am not a motorcycle mechanic, I just play one on the internet.

There is only one way to learn about jetting. Go buy a good range of jets from the dealer and start messing around with it. Good luck. Write down what you do. After a year of jetting you will have a nice baseline for different weather conditions.

Good luck.