Originally Posted by F_Rod81
All of your concerns are valid, but if you ask me.... you can only experience it for yourself, don't base something off of your reading.
A lot if not most of the bad reviews are from those that are either inexperienced mechanically or they don't take the necessary steps to help the engine for the better. Any china 2 stroke kit can be made to be very reliable just depends on the owner. I have over 5k miles on my Chinese kit and have only encountered minor issues. If you like to tinker and tune with things, then the simplicity of the 2 stroke kit is a good option, the china kits will teach you a lot. If your not one for tinkering and you just want to get on and ride then I highly recommend a 4 stroke kit.
Listen to this man. Frank is an experienced builder who rides fast and reliable bikes. I've ridden many miles with him.
Properly installed and properly maintained, there is no reason why a person should not expect thousands of miles of reliable riding from most any of the Chinese engine kits. Yes, there are the occasional lemons that comes along but you might get one of those when you purchase anything. Ask my neighbor with his new Acura that spends more time in the shop that his garage.
Generally speaking, the lack of mechanical skill/knowledge is more the culprit when it comes to problems with these little toys of ours and that goes for the engine, the accessories including the sprocket mount (rag joint). I have thousands of miles on three of them with nary a problem. I do use a home made sprocket adapter on one bike but that was just an experiment, not because the rag joint didn't work.
The same goes for all the complaints I read about the poor quality fasteners. Here again, the lack of mechanical skill is the main problem. Overtighten any fastener regardless of quality and eventually something is going break. Either the fastener or the threads in an aluminum casting. Proper use of a torque wrench is one way to eliminate this problem along with avoiding the advice to "tighten all fasteners after every ride". That lame advice is probably responsible for more fastener/thread failures than any other aspect.
As in any hobby/sport/endeavor, some basic knowledge is essential for success. I often see posts here that will read, "I have no experience with motors or tools but I want to build a reliable/fast/fun motorized bike". We all try to help these people but there is a good chance that this person will not be able to get the maximum enjoyment from his project and most of you will agree as to why.
Sure, everyone has to start somewhere, but I still maintain there are prerequisites to success and without them the builder will suffer some disappointment before he reaches his goal. Comparatively, the builder with years of mechanical experience in his or her background will be way ahead of the game. New, inexperienced and mechanically challenged folks should be made aware of the requirements for success. I guess that's all I'm saying.