iyesterday i fired my first grubee skyhawk, it runs great i only have about 3 miles on it but is very smooth running have an alighnment prob with the rear sprocket no biggie, also have a 49cc grubee with lots of miles kinda my daily driver never a problem with it a hau sheng 66cc same thing no probs after getting everthing adjusted proper, it loves hills!but, if you compare the grubees to like the hau sheng this differences are obvious the casting are much cleaner and the overall workmanship is much better, just one more thing break these things in well take yer time. give em plenty of oil stay off the thottle dont think you can go 30 right out of the box when i fired up the skyhawk yesterday it was very sluggish at first but it only took a couple miles of moderation and it started to light up28:1 fuel for break in, gonna go out soon and fix the sprockrt and will get back, have a great day guys, frank