I just joined this forum and thought I'd respond to this quite old thread!
I've owned my '82 MB5 since the late 90s. Has a little over 4000 miles on it now, but still looks just about the same as in this pic. Stock except for one more tooth on the countershaft sprocket, and a gel cell battery now going on it's 5th year and still working fine. Also have a little tank bag on it now. Did a top end on it when I got it at about 2600 miles, but it looked like it didn't even need it once I got it apart. Put some NOS fenders on it, front and rear. I've riden the "50cc True Grits fun run" with my MB twice, and hope to make it again this year after missing it the last 4 years or so. Plenty of 50cc bikes there of all types. I've also ran the parade lap at "Mid Ohio" sports car course with the MB5 which was a blast. Pretty cool to pass the Goldwings on the curves...
Any other folks into 50cc "street bikes" in the middle TN area?
Glad to add to this thread with my black MB5
(I also have a highly modded stroker SL125 (150) that I have raced in the classic 125 class, and also still have my first bike a '73 Honda XR75. Well first "real bike", the old Rupp doesn't count does it?)
GK