Gents,
You've provided lot of good technical advice, food for thought and moral support. Thanks, guys.
Muskie, yep Timeserts do seem that they might be the cleanest ultimate solution. I don't think they make them in BSW, but maintaining thread originality on this bike may be the least of my problems.
Graybeard, the deal with the Austin sounds like tears must have been shed. It's OK, you're amongst friends.
e, I assume the forum confession booth is open 24/7 to cover all time zones or just messing-up late into the night. With the Alu Weld, is it possible to get down to the bottom of the hole?
Bill, I think I remember you telling us the story of the bad threads in the barrels. I do think that, for now, my easiest way forward is a bit of relief in the inner timing cover. As for full contact with the shoulders around the holes in the covers, squaring the heads to slant won't work (if that's what you meant) because they won't be in the same rotation twice (come to think of if, I suppose you could force that issue). I think with the force required to hold the timing covers in place, less than perfect circumferential contact will be OK, in any case, if anything, the uneven force might tend to mold the shoulders to the matching slope.
Bob, I do think that I will opt for being able to ride over solving this problem right now. Your compliment regarding my persistance is generous and appreciated. Hmmm, valve guides? Do I use the same confessional for that topic or is there a dedicated one? After I installed new ones, following reaming, the machine shop pointed out that the valves set a little funny in the head. (Oh God no! This turns into another off-angle story!)
TT, That's interesting, going with the tap, only. Sounds like something I'd like to experiment with, but in a piece of scrap and not with the precious tap that came with the helicoil kit.
John: Wish I had done the drill-in-a-tap-wrench approach, as it sounds like a safe solution. In the afterthought of this, it occured to me that an old inner cover fitted with drill bushings installed would make a good fixture. I also like your idea of the one-hole-at-a-time fixture.
Morris, Very clever, basically making your own Timesert and maintaining BSW.
Terry, Your tweaking the bolt idea is a another experiment I might try in a piece of scrap to see if the helicoil can moves enough in its hole while staying stable enough to do the job.
One of my ideas for a possible fix involves another experiment in scrap wherein I drill an off-angle hole and tap for the helicoil. Then, drill a perpendicular hole (with no helicoil in place) at the same center. Then, run the tap down as near to perpendular as I can get it. Then (have I reached my "then" limit?), install the helicoil using permanent Loctite. Before the Loctite sets, run in a screw with antisieze (to avoid the Loctite) and try to assure perpendicularity of that screw until the Loctite sets.
Thanks, again, guys. Looking forward to more thoughts. I defy you to find anything on YouTube that touches on this subject.
Richard L.