The basics:
186 yanclone engine
Norton Atlas 4-speed transmission with Commando mainshaft and belt-conversion diaphragm clutch
Wheels, forks, swingarm, etc from 1972 Honda XL 250
Tig welded 4130 steel frame, made in sort of a Norton Featherbed style
3.5 gallon 5052 tig welded aluminum fuel tank with rubber mounts
DOT legal LED head lamp with high and low beam
LED signals
This bike consistently gets 100-110 us mpg.
It is titled in California as a "Special Construction" vehicle and is fully legal on all roads. It has a VIN and there is no trouble with registration.
The weird:
It is tall, less-than-average height people might have a hard time flat-footing.
The wiring should be redone. It basically works, but the voltage is always low and leads to weak battery after a few days.
The kick-stand spring is weak or should be repositioned, it can droop down unless it is leashed somehow.
Its, you know, a loud and shaky single cylinder diesel bike.
I have just over 5,000 miles on this bike. Mechanically it has been super reliable. In the first 1,000 miles I had a lot of issues with things just shaking apart, but since then it has all been trouble free except for the slowly draining electrical.
Me and the bike are in Los Angeles city.