I had a 1980 cm400t back when they were a new item, I now have 3, {restored two} for my kids
first road bikes, If the fenders,gas tank etc. are not rusted,and it was cared for, they will run
forever ,with normal maintenance. new synthetic oil ,will eliminate most of the "running hot"
problems, as well as going {one} step richer,{larger} on the low jets{idle circuit.} for reference,
Haynes Carburettor, and fuel systems Techbook, covers this pretty well...
good Luck