Replacing the hacked up subframe on my bargain find, and I'm seeing now why the upper mounts were short thru-bolts with nuts on the end, instead of being bolted straight to the frame like the fiche diagram shows -- the hole's stripped.

At a glance, I really don't see why it'd be a problem to just run with that forever, there doesn't seem to be anything that needs clearance on the inside. Am I missing anything? Should I splurge on a helicoil kit? If so, is it 1.25 pitch or 1.5?

 

There are 4 bolts that hold the subframe on, lower two ARE through bolts with nuts on the back side..
Upper two are bolts into fixed threads in the frame.. I assume your re asking about the upper two?

If your ok with the thing being hacked, and the hassle of needing two tools, leave it as is...not going to hurt anything.

As a personal opinion, Id fix it right.... Thread repair coil set is not a single model, or even motorcycle only repair set...So I tend to not even think of it as a repair part purchase...or if I was adding up costs, Id look at the thread repair coil cost for the two coils used, and consider that the $$ number to add.
The rest is just tool cost.

To each his own, Id fix it .. you may not.

 

For me I have thru bolts on mine due to a little sink hole I hit on 2nd ave in Manhattan. Sheared the originals right off. I didn't trust the aluminum threads after I saw how they faired in the hit so I just nut & bolted them.

If you are doing multiple repairs as I was it just didn't seem worth spending extra time on an invisible fix that wont get touched again maybe ever.