So I got this Jawa for a case of beer from a coworker about 2 years ago. I didn't do much with it because of other projects until about 6 months ago. The piston was stuck so I did a complete rebuild of the motor; seals, bearings etc. The cylinder is bored out to the third bore size with matching piston. Interesting note on this cylinder is that there are boost ports in it and the stock head has no decomp lever. 14/12 Dellorto SHA. I finally got around to hooking up the electronics to check for spark today and low and behold there was a nice bright blue spark. Oh yeah those are Maxi forks on it.
Just thought I would share. More updates to come. Also, I have no idea if it is a Supreme 2 or 3 and don't know how to tell. Vin plate doesn't say either.