This an 80's JMC 3.1XL.
It was totally tricked out back in the day by the engineer father of its young owner.
This bike was converted to run 24" sew-ups!
As you can see, the brake bridge was relocated and the fork crown was shaved to accommodate the 24" tires.
There was a repair made at the downtube as shown.
The fork dropouts were machined for weight savings.
Tires do not hold air.
Many other parts were also machined to shave weight. Even the stem quill was drilled!
This is a super cool survivor work of art. It oozes Old School BMX history and would be a great conversation piece or wall hanger. It can be used, however if you have a little one who is up for being the coolest kid on the planet.