Had the Derbi out this weekend, and rode about 60 miles with me aboard. Kinda windy, and the Derbi struggled a bit on the hills with the wind and a 180# rider.
Went to the semi-annual Slimey Crud Run in Pine Bluff, WI, and pulled-in next to this beauty -
Bimota V-Due 500cc 2-stroke - https://en.wikipedia.org/wiki/Bimota_V_Due
This one has been totally redone to actually work. Long story, that I got from the owner, but basically the engine cases were a problem originally. By the time Bimota figured it out they were almost broke.
Factory engineer bought everything (bikes that were bought back, unassembled bikes, all parts) and had new cases made, as well as going to carbs instead of the problematic F.I.
First one I've ever seen.