Isolastic mounts journey into the unknown

Really curious about the differences in isolastic mounts. I have a 1972 Interstate 750, and also a Mfr date 1975 MKIII 850. The Interstate and the MKIII don't have original exhaust pipes. This is the story as follows. Was working long hours the last couple of years, so I took the Interstate in to be about a 50/60 % restoration. I received the bike back had a few oil leaks problems (what's new) which is understood with British bikes. The bike had been sitting for about 17 years, so I had been increasing my trips from short runs to longer runs to let any problems surface like a shakedown cruise (term fits). Anyway after a good run of say 60 miles an hour or so, the right side header pipe loosened up, and at the connection at the muffler. The clamp on the connection tying in the header to the muffler was played out, it wouldn't clamp down any further. I have also had this problem on the MKIII. It also has a hanger plate fabricated by the mechanic to accommodate the mounting of this exhaust set up. At that point the isolastic mounts had torn near the fabricated hanger. Along with the carburetor nuts also loosening up on the studs so badly that at least two fell off (fortunately due to tight spacing, the nuts weren't lost and just sat jiggling on the end of the studs. I took it back to the mechanic as I have only had it for a week about the oil leaks, which we surmised coming out of the rocker covers, and small plates adjacent to them. My mechanic spoke to a more informed NORTON old timer who said it could be the isolastic mounts causing this, vibration, working. The bike have just over 20,000 miles. Is there any inspection, or test that can be done to the isolastic mounts?
Just curious as if anyone has run into this kind of problem? I did have it on my MKIII which at the time was fitted with new exhausts due to an accident in 1976, the old megaphone exhausts could not be found to return to original, I solve it by reworking the plate, and shimming. I also had a small problem, with the allen, or hex bolts loosening up on the intake ports on the head, which I cut down a wrench (to facilitate using the wrench due to limited space) and applied Locktite, which worked fine. So if anyone has any input or tales of woe , frustration, and finally success, I would love to hear them in this regard.....of isolastics... Also the options, and difference in types of isolastics i.e. Vernier, or whatever, as I am ignorant in isolastic expertise at this point..

Pictures please.

Have a read through this: engineering-compromises-leading-exhaust-threads-stripped-t14363.html

The exhaust system is a huge compromise, JMWO :mrgreen:

>>>>>Is there any inspection, or test that can be done to the isolastic mounts?

By the time you get the ISOs in a position to evaluate them, replacement is right around the corner. Your ISOs died years ago, they do not live forever and they slowly lower the engine/transmission/cradle as they give up the ghost.

The symptoms you describe are a clear tale of worn out isolastic rubber "donuts". Once they harden (from sitting) they go downhill VERY fast, and fall apart.

Do a search of the forum for an easy way to replace them without having to totally drop the engine.

As far as the vernier type for the isos, you can't go wrong with the Hemmings adjusters. It replaces one of the end caps on the front and rear isos. Other types may require buying all new parts, not just the rubbers and there's at least 2 other types.