Need 4 stroke kit recommendations please!


Aug 31, 2010
Rochester MN
As the title says I'm looking for advice on which 49cc kit is the best. Im going to be helping a friend build her cruiser bike. I only have experience with the 2 stroke kits. Im particularly worried about the belt drive transmissions, I have heard some of them break easily. From what I've read it sounds like either a kit with the 4g or the 7g box is the way to go? Is there anyone who can tell me how reliable either has been, or what modifications were needed to make it reliable?

This may seem like a trivial question but after google searching and searching forums extensively I have yet to get a clear cut answer. I tried to answer my question without clogging the forums hope I can be forgiven haha.


Jul 17, 2008
The belt drive works great however the 4G plastic cover is really bad and breaks easily where it is mounted with the screws. What I did is make an aluminum band around the perimeter of the plastic cover and drilled holes where the screws mount through. That held up pretty well.

Also the kit came with a long axle for the crank shaft which was made of soft metal and easily bent. That caused the sprocket on the right side to derail the chain due to some really terrible run out whenever I pedaled. make sure you have a decent crank set with wide crank arms to go around the transmission.


Custom MB Buiilder
May 7, 2008
Houston, Texas
Till I find the answer, I have a Grubee Transmission the old one. I have a Honda GHX 50 motor, brand new. The transmission is missing some washers & misc parts. Can I send it somewhere to be looked at? Also I need a motor mount to install it in a 26 inch bike frame. Does anyone know where I can order a mount? Have a new Titan carb for it. Will need a pipe also. Any help will be appreciated.