Yeah, that model is just as important to keep full of good oil as well as keeping it full as the 85X.
The good part is yours runs on bearings so the head is still good; But, it does need port work IMHO.
You said the chain had the cover plate, that's about all that guides it, they're always loose as a goose. They have everything and choices of shipping as well.
I was about 18yo when I bought an 85 and and a 86; That 86 was my buddies and he didn't do any maintenance. I foolishly bought 2 new rocker for it to quiet down and sold the damn thing. It needed a cam bought all I could, I had 0$ back then; Aside from 3 paper routes, lol.
Very important to replace all the parts at once. But, I was broke and it was ticking just a few months later.
I think that oil seal for the decompression shaft is DC'd, but Eastern bearing in MASS (ask for Butch ), and he'll give you pptionns. he is very helpful and I think hr gets "rubber coated seals which are 1mm short nut works fine. Do it once, do it right....
They have all our bearings and seals; Just mention ME when asked. They have some bushings too short or too long, but that's chicken........
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country