My sons new automatic 50cc bike has almost now take off power. It will just barly begin to move at 1/2 throtle.

At WOT it will still loose power on my back lawn & its almost flat. On paved roads its VERY fast but just has no lowend power.

Can i change the springs in the clutch to help this?
I have already gone from a 14 tooth to a 12 tooth drive sprocket & may swith the 37t for a 42t on the rear.

Could the clutch be messed up?

Please help!