I voted poor for a few reasons,
During a ride, one of the head studs made a loud pop and i immediately knew what had happened, it had pulled out of the engine block and ruined the threads, requiring expensive repair
when i went to remove the engine from the bike for simple maintenance (other than the stud) and checking all bolts, the screw holding the clutch cable to the lever it lost it's head
the rear motor mount broke out of the crankcase (both minor issues, but a pain in the *** to fix)
THEN, i looked at the cylinder carefully after removing it to clean carbon deposits, and noticed that it is not even remotely close to smooth, there were obvious spots of both excessive wear and areas where carbon was filling in divots in the cylinder
I called king's expecting at least some cooperativeness because they gave me a three month warranty which i am still in, but i was rudely turned down.
they told me that they would only send ANYTHING to me if i had called with a problem within a couple weeks of receiving it..... when i asked about the three month warranty they avoided the topic
basically, it's not even worth it to repair this engine, i'd rather buy one from a company that actually follows through on its warranty