Looks to me the mighty TS185 has plastic levers and PP Mudders too!..that is one trick bike with some serious patina you have there Bill! serious! fit a hooker pipe and an era plastic vesco tank and it's the complete deal
Tony, I'd probably just give it a wash and rub back where ever needed, a splash of black, a couple of tank emblems and ride it as is
Firko, I hate to give wrong advice so I'll say this, the later black '76 TS would be the best to hot up due to having a little extra something but I'm not sure if the electrofused barrel could be 'cost effectively' modified..
..Lozza!
Swap the gear clusters, primary drive and ignition for TM items and retain the TS cases to match the later TS cylinder (the later TS also run a normal 2 bolt rubber push in type carb spigot ala TM which save manufacturing anything). Someone like me takes the easier way and uses the normal '74/'75 TM or TM styled TS bits because there's no chrome bore to worry about but for actual outright HP I'd reckon a modded '76 TS would deliver the most ponies. This is all only if the cylinder could be effectively replated or maybe even rebored to a regualr oversize after the port work. Again, I assume the grand master Loz will know the answers
Most of the difference with the 72-75 TM/TS is the early J and K had the pushrod operated clutch setup. Different outer cases and longer selector shaft but the rest is much of a muchness right through. Early exhaust exit angle is different also, a minor issue. Personally I'd use the '74/'75 TM but it depends if you looking or can afford the absolute which dirt track requires.
Another big question here, is the '75/'76 TS a follow or not? same goes for the '76/'77 TS125, are they a follow on or flow on?
I really wish I knew for sure.