Gearnut is right on the crap shoot statement, but there are more good ones than bad ones I believe.
(Bad ones die in the hands of good MB builders & good ones die in the hands of bad MB builders)
Many good engines have bit the dust from poor actions during and after the build......take time to build it right based on the large amount of very helpful/useful information you have at your finger tips right here on this forum.
I see no reason to believe this is a bad kit, the add says that these engines have been test run for at least 10 minutes, so if this is true and the people testing them refuse to box an engine that is rattling or acting up in any way, you should be getting an OK set up.
just remember that upgrading the mounting hardware with at least grade 5 bolts/studs will really help to make sure your engine is solidly mounted and will stay where you put it and not be breaking studs right from the start.
I've looked at this kit myself and wondered how well these engines will actually perform compared to others.
Best wishes.....!
Peace, map
NEW 80CC 2-Stroke Gas Engine Motor Kit For Bicycle Bike | eBay
Just wanted to post the kit I was getting before I got it, just in case it happened to be a horrible horrible kit and some of you could save me from disaster or something.
Basically I Wanted the cheapest kit I could get and hopefully get something that will last me at least a year