The fork cleaned up nicely in preparation for painting. I half expected to find a crack or two but was pleasantly surprised to find no cracks. It is quite different from later forks. It is 3/4″ wider and has 7/16-20 UNF nuts welded in the top to accept the handlebar mounting bolts. I used a 7/16-20 UNF eyebolt from an old Plymouth Barracuda to hang the fork for painting. The horizontal braces were not painted green underneath so I suspect they were added when Jim Cavanaugh upgraded the bike.
The bottom bushing was a heavy press fit which will require reaming to accept a kingpin bolt. I was able to push the top bushing in with my thumbs and it accepts a standard size kingpin bolt nicely. I am not surprised that the fork will not fit onto the frame fishmouth without some work. The fishmouth measures 4.494″ across the mounting bosses. The fork measures 4.434″ inside the new bushings. I will have to reduce the flange thickness of each bushing by 1/32″ to get this to fit. The next problem is the welded on bungs with the bores each measure .660″ thick. They need to be .625″ or thinner to accept the FB1012-6 bushings correctly. .660″ means the kingpin bolts will lock up on the bung instead of the bottom of the bolt shoulder. All these bad dimensions explains why I see so many hammer hits on the fork. Instead of correcting these issues someone just beat the fork on. Thinning the bushing flanges and extending the kingpin bolt shoulders even more on my extended kinpin bolts will fix this problem. What is truly amazing is neither Nerthercutt or Rokon ever figured this out. Instead they jammed set screws into the kingpin bolt threads to keep them from backing out. Looks like they gave up in 1986 when they switched to the bearing head steering forks.
3/8-24 UNF nuts are welded into the bottom of the tubes to accept the chain adjusting bolts. The brake anti rotation bracket was welded on about 5 degrees out of alignment which wore one of the brake shoes crooked. I straightened the bracket with a crescent wrench.