Puch Magnum II - Untitled Thus Far

Have you checked your plug color?

Edit: Chocolate or coffee brown would be where you want it. Black or oily is bad, as to too white or grey.

As far as the sound and feel of the engine goes, if it's four stroking at wide open throttle top speed (firing every other rotation), that's a sign that it's running rich. If it's just lacking power, then it's too lean.

Here are some links:

Plug Chop
How Far from Four Stroking