Welcome Robert to the forum, glad you joined us
What kind of bike to get?.....
http://motorbicycling.com/f3/what-ki...-510.html...In the link you will find measurements for the bicycle frame.
What kind of motor?....
http://motorbicycling.com/f4/kit-best-1764.html...
2-stroke's are cheaper, a lot of maintenance and lighter.
4-stroke's are little more expensive, weigh more, less maintenance.