I did this repair on a friend's Busa and this is what I found out in the process. FIRST, there's only so much meat to tap into around the drain hole so a Helicoil isn't, maybe, your best choice. SECOND, only a small amount of the pan material will actually grab the helicoil as the sleeve that sticks up has to have a slot cut into it for proper draining.
I discovered that a Timesert, or steel sparkplug repair thread (which looks exactly the same in most respects, might be one of two better choices for this repair because they are both "one-piece" units. Once installed, you can flatten the outside to match the natural pan dimensions for drain plug / washer sealing, AND (here's the best part) the inside can be match-cut to the inside of the pan for optimal oil drainage.
I got a hold of a machine shop here in Vegas that does this service all the time, and $50 later I had a stronger threaded pan that will never leave the bottom of his engine for the same reason unless he torques the drain plug "WAY" past 16.5 ft/lbs...shall we say 100 ft/lbs ????......No really.....
The problem with the factory arrangement is that they should have threaded the aluminum pan with steel threads to match your drain plug's threads. Too many in-and-outs for oil changes and the aluminum threads simply get soft and worn, UNLESS you are critically careful about oil changes, which none of us are.......
Call a couple motorcycle shops, ask them who they use, call that shop and I'll bet he's doing the same basic thing with a steel insert. Machinist's are usually pretty savvy about installing things like these, respective to their intended use and abuse potential.....you'll never have this problem again.
Get a new pan gasket, get the pan repaired properly, and torque the little 8mm headed bolts to 1kg when finished with a little blue loctite on them and it's a DONE DEAL Bruddah !!!
You drain plug thread is 14M (mm)X1.25M(mm).............or 14Mx1.25 :oldcool:
