Yesterday I stripped the front end off the '77 GL1000 roller that's been sitting here for over a year sans engine, with the intent of using it on my CB750. Luckily for me, the GL forks have Progressive springs in them, but the old alloy air caps were pretty badly weathered.
I hunted around my garage and found a NOS of S&W Air caps for some unknown forks with the right thread, but the threaded portion was around 6mm too short, and even though I could screw them in a couple of turns, it wasn't enough.
I chucked the fork tubes in my lathe and machined off 6mm from the top of each tube, and Voila! The caps are a good fit.
Before:
After:
The're not the best forks I've seen, but after I cleaned them up with some 800 grit wet and dry paper and WD40, I removed any rust and high spots (someone had clamped them in a vise and gouged them in their 37 year history) and they should work fine. Good news is that they're both straight.
I also stripped the paint off the calipers and triples, and I'll give them a coat of paint tomorrow. Cheers, Terry.