Re: Hello from Boise
The Chinese in frame 2-stroke may do you well, but they do have their issues. Just read through some of the posts in the 2-stroke section and in frame section and you will understand.
I have a preference to the 4-strokes myself, using a ShellyBelly Whisper Drive or a Q-Matic. You could also use one from Thats Dax, Bicycle engines.com, ect.
Browse through the vendors on the left and right of the screen, there are alot of in frame or forward mounted powertrain options.
I am still sitting on the fence concerning the 4G transmission. They don't seem to be built as good as Whisper drive, or Q-Matic. Another thing to consider, both ShellyBelly and Q-Matic are coming out with automatic 2 speed transmissions. More torque and faster top speed, and still the (IMHO) benefits of a 4-stroke engine.
They are quieter, you do not have to use pre-mix oil, they produce more torque, are more reliable, and get better gas mileage. The 4-strokes also cost upwards to 3 times as much as a 2-stroke.
I cannot recommend one kit for you, they all have their good points, and bad.
"It's a chinagirl. It's a sometimes fun little engine that often will break your heart. It's disposable.
Does not come with a fortune cookie."