Re: Whizzer motor vs huasheng 49 cc
I've never had a Whizzer engine, but I know quite a few who've had one. I almost bought a new one in 2010 for my bike, but research dissuaded me.
Instead, I bought a Huasheng. Since August 2010 I've put ~6K miles on it and have had zero engine mechanical problems. Just a couple gummed carburetors.
The Whizzer engine has more torque and much more potential horsepower. It's also considerably more expensive. It will likely need work to keep running.
The Huasheng is cheaper and will tend to be more reliable - it's a utility engine, made to run all day long. Whizzer engines can be very reliable with a bit of work.