J–K models use the black plastic version of the chain guard. I was fortunate to obtain one of the last remaining original parts from the 1972–1973 production years.

Item No. 14, the metal reinforcement plate, was missing, so I had to fabricate a new one.

The part should have been made in steel, but I chose to manufacture it in aluminium, as shown in my CAD model. After a trial 3D print in PLA to verify the dimensions, I machined the final part from 3 mm aluminium on my milling machine and tapped M6 threads.

Please feel free to downlad the STL file.

For extra strength, I added a nut to improve clamping, since the part was only 3 mm thick.

The chain guard is now mounted on the bike. The screw in the frame will be replaced with a countersunk version at a later stage.