Join Date: Sep 2006
Location: Oshkosh, Wisconsin, USA
There will likely be several opinions on how to best fix this, but you will likely have your own comfort zone. A few options here; Heli-Coil, threaded plug called "Keen-Serts" or something, or tapping a little oversize are a few of them.
Since the repair must contain slippery oil under variable pressures, you need to maintain the sealing face. I haven't had this problem yet, so I never paid attention to the fork drain screws' design. Are there O-rings involved, or just little sealing flat washers?
Without seeing the feature 1st-hand, I think I would research the current size thread size, and compare the closest "next size" between both metric and english, to take the screw a little oversize while still retaining the original sealing surface, then re-thread. Make sure you have a suitable replacement screw in-hand before you make the committment, though.
The HeliCoil would be my personal next choice, as they have always worked well for me in salvaging spark plug holes, but I don't know how small the thread sizes are available. I think I have one kit here that is a 6mm, but not sure...might be 10mm (memory is the 1st thing to go, don't'cha know?)
I do all my own stunts...