Re: grubee skyhawk 66/80cc
In the current market of 80cc/66cc engines, I don't think that there are any providers of engines that are "just fine out of the box". There are several very important parts that should be replaced before installing and riding. Swapping out the knuckle bearing with an aftermarket one is very important. Just an example: the stock bearing can be replaced for about $0.75. A good aftermarket bearing can cost $15 or more. (I bought a $10 "racing" bearing for mine.) The stock bearings DISINTEGRATE at the slightest notion. All of the stock nuts and bolts are very low-grade steel, so any of those that you can replace will help significantly. The stock plugs are garbage. The stock mufflers are pretty crappy too. Quality control on china girls SUCKS, so the buyer must control the quality. A tear down and rebuild before use will greatly improve reliability. The more thorough, the better.
I'm just waiting for somebody to set up their own tooling for one of these engines, then make them with good quality metals and parts. Of course, that would then probably cost as much as a four stroke. Still, a bullet proof china girl would be AWESOME!