i wouldn't recommend the grubee skyhawk kits to anyone. sadly, they're the only ones currently legal to import from china. everyone i've built had problems. blown head gaskets, bad magnetos, weak pistons.
something as simple as a ring keeper on the piston can break loose and destroy your motor. i was trying to make them faster and more reliable and offer them for sale, but instead, i'm in the hole with a pile of scrap aluminum.
grubee's poor quality has totally turned me off of the chinese 2 stroke. in fact, i need to rebuild my race motor for the 4th or 5th time, and the bike's got less then 100 miles on it. every engine failure was caused by crappy pistons.
part of the fault is i'm modifying them to go much faster than stock and the pistons just can't take it. but people have been modifying little engines for 100 years with good results. it's sad when you can't even build the kit straight outta the box without something failing right away. add a little more power and watch all your hours of hard work explode on your way home from 7/11.
reliability from a chinese two stroke? good luck. making money selling them? good luck. fixing bikes you've built to try to keep a customer happy? get used to it.
bitter? yeah, a little...