Re: Best engine kit?
First welcome to the forum, your question has been asked many time here. All of the engine kits are made in China in several different factory's, some are of better quality. What some of the suppliers of the higher priced engines do is disassemble the engine and replace parts like bearings with upgraded versions, some even check the balance of the crankshaft to ensure you get a good running engine. As for building a bike at home that depends on a persons mechanical knowledge, you do have to fabricate some parts and pieces at times.
Your results may not be the same,Greg