Alright here's a bit of info on this swap, note that this might not be significantly cheaper than custom triples.
2000-2007 cr125 forks
~2002 vtx 1800 triples
200x front hub
All balls taper bearing conversion for the head tube
Alright so you will need to press the steering stem out of the clamps. Take the clamps and forks to a machine shop, the bottom clamp will need to be bored ~1 mm over, best to have the forks with you for a good fit. This is where it stops being cheap; the top clamp is too large, I had them machine me a couple sleeves out of aluminum, with a small flange so they won't fall through. You will have to grind the steering stop down significantly, but you can use the stock steering stop on the frame.
You will have to have the steering stem turned down. The top bearing surface has to be brought down on the shaft ~1 5/8". The bottom surface will have to be turned down to fit the bottom bearing. The bottom bearing is slightly larger ID than the top. MAKE SURE THEY DO NOT TURN DOWN THE STEM WHERE IT PRESSES INTO THE TRIPLE. I still need to work out a shim stack. I'll get pics when I actually have the triples on the bike.
Center to center the forks will be ~10.5 inches. Front hub is a TIGHT fit, you will have to get rid of the studs on the rotor and run countersunk Allen head bolts, or regular bolts with slight grinding on the head. You CANNOT run an 8" front tire, it will not fit between the forks.
This is as far as I have made it. I'm not sure but I THINK the stock rim will fit, not sure if brakes are even possible. I wouldn't recommend doing this, at least until I finish mine, just in case it's not viable to make this setup work.
That's the approximate ride height with a 23.5" front. Stock clamps have a few degrees of rake built in, these have zero. Looks like it will turn out to be pretty good as is. Steering stop can be ground down a bit on the end for more turning.
Yes I used a bunch of 1" washers for shims, no I don't care about your opinion. The bottom spanner with the dust shield was ground out, instructions said to use a nut with a dust shield, and since the vtx 1800 stem is longer, I ground the threads out to use the nut as a washer so I would have the dust shield. The washers will get replaced with collars cut to length for the final. Sorry about my iPhone turning the pictures sideways.