IME - Self taping oversize plugs tend to keep "self tapping" and remove the threads with just a couple plug in/outs. That would not be the best choice IMO.
You could:
- Replace the pan
- install a Heli-coil, i.e. install steel threaded insert.
- tap and install a ball valve drain plug (you could thread lock or epoxy it in)
If it were mine, a heli-coil would do the trick. A complete kit comes with a drill, a tap, coils, and installer device, and likely some thread lock. Make certain the length of your bolt will not bottom in the insert. If it does, you need to shorten the bolt or get a longer insert. If the two meet due to the bolt being to long, it can cause the insert to back out.
For the install you grease the drill and tap to try hold the metal chips on them so they can be extracted. Some extra oil to poor through the engine to get the metal shavings out At least a Qt or more. PS - nothing says you can't drill while OIL IS pouring out (even old oil!). Its just messy! It is highly effective at chip removal. If you do this, DO NOT USE GREASE!
Grease drill bit and drill hole to over size. Grease tap and Tap hole (cut new threads for the heli-coil). Use a Q-tip and grease to remove shavings. Poor oil through filler cap and flush out shavings. Repeat, repeat, repeat.
Tip bike to keep oil from coming out of hole and clean fresh threads with brake cleaner. Clean insert with BC. Apply thread bond to outside of insert and use the tool to install insert to depth.
That's the just of it. I'm sure you can find a utube vid on it.
ALSO - you could pull the pan too and not deal with the chips in the engine. I've gone so far as to stick a vacuum cleaner hose up to the pans hole to remove chips. It works! You MUST REMOVE THE FILL CAP THO!!.
EDIT: It can go easy and in cases it can go wrong. You need a good drill with a chuck capable of holding a large bit. You also need a good sense of alignment to drill the hole and start the tap straight, not off to the side. If you don't think you're able to square up the tool and drill & tap a straight hole, remove the headers and pan and take the pan to someone who can. The BIGGEST MISTAKE during the thread cutting process is not pushing hard enough and squarely. Followed by removing the tap before an actual thread is cut. Thus, going back in you start threads a few degrees different location and waste precious material. Ping me if you choose the heli-coil path, there are more tricks.
