My huasheng revs to 9300 without a load and does 45 mph on flats. Its probably got somewhere over 8k miles on it, most likely more. Been wanting to get a speedometer that keeps track of milage but they don't seem reliable enough to go that far.
Those little motors seem nice they’re cheap too. They sound nice with a long straightpipe. The bearings get better lubrication since it’s all oil instead of diluted oil and gas. I wish I’d gotten one instead of a 79cc
When the weather is colder these little 4 strokes need additional throttle opening when you set the choke. Not an easy thing to do with the spring loaded carb. My GX31 needs the twist throttle adjuster screwed out about 4 turns to open the throttle enough so it draws in enough mixture to start on full choke, otherwise it won't even idle, takes a few minutes to warm up before I run it under a load.