I thought I would have a look at the back wheel, I bought and ran a 3.5" D.I.D. alloy rim with a 130/80-18 tyre many years ago, and it worked well. It cleared the chain and guard...(O.K. small bite out of the guard), and the Brake torque arm was shifted outboard about 10mm. Here is one for you, everyone and his dog has drilled discs, but how many of you have (TaDa) a drilled DRUM....?
Now, I am not sure if this modification helps unsprung weight, aids cooling, or let's the "gasses" out....but I reckon the "cool" factor is right up there....I'm running with it! So, polish the rim, new bearings, a new Dunlop (Sumitomo) 130/80-18 TT100/K81, (soft compound "GT" spec). Stainless spokes and a new 45 tooth sprocket which I had Lying around, which will bring the overall gearing just under stock with the 14 tooth C/S sprocket I have. (and just over with a 15T.)
Then we will give it a few spins and if it doesn't stop in the same place after 10 spins, I reckon it is balanced...... (I have ridden a H2 with a bald back tyre, so I know they can get a bit "nervous")
New brake shoes in the back (DO NOT use "old" brake shoes, they can separate and lock up your wheel...). A lot of guys don't use their rear brake, that is fine, but given the rearward weight bias of the old Triples, and for me , the ability to set up a corner with a bit of rear wheel steering, I am a fan of rear brakes......! (Plus I had a '70 H1, which didn't HAVE a front brake....!)