My 45 Zokes were trashed in the inside as well. The oil broke down quickly, was very dirty.
Here is what I did:
I found a complete front end from an 03 EC300. The forks were 43 WP's were a direct swap.
You will need the following to make the swap:
1. Complete forks and axle.
2. Triple clamps, stem bearings, dust caps, washers and lock nut and top nut.
3. Nissan front brake caliper, hose and master cylinder
4. Axle spacers and hub spacers (inside hub)
5. Bar mounts if going to oversize bars
6. Wheel bears and seals
7. Plastic fork guards with hose clamp.
8. I bought a plastic front brake guide for a KX100 and mounted it on the clamp to keep the brake hose in check.
The conversion is a direct swap, no messing around with machine shop's trying to get some KYB forks or clamps for a trashed YZ to fit.
Save yourself the pain, buy a COMPLETE used GASGAS front end from the steering stem forward and the transformation will be completed in a day.
Get the forks service and go ride!