Yup, I agree that a bad stator could be the problem. The stator is nothing more than magnet wire wound around an iron core. The wire is small, and wraps more than 1000 times, so if you get a bare spot inside the winding, the result could well be low output. Are they installing a new stock stator plate or just an after market stator coil? Kawasaki does not sell the stator coil or CDI trigger separately, so you have to purchase the entire plate and components as one unit. Unfortunately, kawasaki is real proud of their unit, and I think it retails at around $300.
Also, I have used the aftermarket stator coils, and was not impressed. I eventually opted for an entire new plate (I think Kawdude now has my old plate), which fixed an intermitent failure. In my case, I beleive the CDI trigger was bad.
Fainally, make sure you get your hands on the old stator coil, as you can use it to make a lighting coil for less than $20. The iron core is hard to find, so a stock stator makes a great start.
Hope this fixes the problem.
Rick