I have about 110 miles on mine now, and haven't had any problems at all - with the engine that is. I tried to contact them via email two times now w/ no response. My clutch lever was defective, and I wanted it replaced. Never heard from them.
I have read how an 80cc doesn't exist, but the manual provides a piston sizing chart for the different displacements so maybe, maybe not.
If I was to buy again, I would go w/ a "ThatsDax" engine or a company that supports this board.
Powerking also does not have a warranty, so you're on your own if it breaks down. Spend the extra buck and get a better one that has a warranty w/ it.
My neighbor has a Dax motor, and I noticed that he got a better performance exhaust pipe, but I got the cool black and chrome handle grips. One other difference I noticed was the Powerking has a threaded seal on he CDI to magneto wires that go into the engine case on the bottom. The Dax motor just had the plain wires. That's important because you want to make sure you seal the magneto casing to keep water or moisture out of it. It will short out the magneto if you don't seal it well. I used windshield repair silicone which is working great. Other than that, pretty much looks the same. Both motors have bearings as opposed to bushings as well. That's a major thing to consider when shopping.
What ever you choose, it's way cool!! - and well worth the investment.
Hope that helps,
Thru in a couple pic's for you to check out.
I painted my motor black, but I have seen a special addition Powerking kit in black if you decide to go w/ them.
The kit does come w/ a tear drop 1/2 gallon gas tank, I just liked the look of my bike better w/out it on the main frame and relocated it to the carry bag on the rack
Troy Fitz.