What on earth could possibly cause an inner primary-to-engine bolt to come loose, fall out, and be found at the bottom of the chain case when I took the primary cover off of my 95' softail classic???

 

I have seen it before. Typically, the bikes that this has happened to had been 'worked on' previously by mechanics that cut some corners.

 

Was there a locking tab found in there also?

 

I see...no problem with torqueing it back in and a little thread lock?...or is that a bad idea for some reason?...and yes Dan, the locking tab was in there as well. All the other tabs are bent up consistently but are not close enough to the bolt head to prevent it from spinning. I'm no HD tech but simple mechanical intuition tells me that ain't right! Strangely there was also what appeared to be about a 1/4" length of the transmission end of the clutch cable!! Weird, like it had been cut off and the round block at the end of the cable that pulls was in there too split in half. Very curious.

 

I think you may have your answer right there. If the tablocks are not bent properly, they can`t do the job.

Replace the tablocks, torque the bolts in accordance with the service manual, bend the tablocks properly and you will be good to go.