Adapting Suzuki GT 750 forks (or any other Japanese fork with 35mm stanchion tubes) to fit a Royal Enfield.
Cut a thread at the top of the fork to allow it to screw into the threaded hole in the upper fork crown on the R-E.
This is a British Cycle thread, 26 threads per inch, 60 degree angle.
Modify the hex plugs at the top of the Suzuki stanchion tubes so they fit flush. This was complicated by the fact that the plugs are hollow, and cutting off the hex section at the end exposes the hollow. We worked around this by drilling the hole and tapping it with a 1/2 inch pipe thread, which we then filled with a hex socket pipe plug.
The bonus to this is that it will allow us to unscrew the stanchion the same way as the original Enfield forks, using a large allen wrench.
Here are the plugs as modified.
To adapt the plumbing from the Suzuki forks, I made up a little bracket to hold the "splitter" that routes the hose from the master cylinder/brake lever down to the dual disks.
The shape of the bracket is dictated by the fact that it has to fit directly under the friction damper for the steering. Carefully cut out to just clear the damper.
We made up a 3/32 inch washer that pulls the wheel over that distance, and re-centers it. The brake disks just clear the fork sliders, and since the calipers are floating, no modification of their mounting was required.
Here's the axle and washer. I used two right side axle spacers because the one on the left side is the speedometer drive. The washer wasn't really necessary, but it makes it easier to get the wheel centered in the forks.
I also used part of the tubes from the top of the Suzuki forks that hold the headlamp mounts to give me something to put the tops of the gaiters over. It attaches the same way as the standard Enfield upper fork covers, using little tabs which are held by the bottom fork crown pinch bolts.