I am planing on building a 4 stroke motorized bicycle sometime mid 2015. I want to use a 2015 Schwinn coffee but I am open to recommended bikes for a build. I do kinda have my heart set on the Schwinn coffee and it looks like it could be a good engine fit without being to tall for me. I am pretty short (5 feet 7 inches) so I don't want a bike that's exceedingly, uncomfortably tall like most motorized bikes seem to be. and from what I've noticed it looks like they wouldn't need that big of a frame size. just seems like more extra unneeded space and frame height. I've ridden on a motorized bike that was to tall for me and it wasn't a very comfortable ride especially during stops and red lights. What 4 stroke bike motors are legal in California and what are reliable brands? I'm looking for something in the 50cc range. (the most common size anyway) So any experts on motorized bicycle building would be appreciated.