I stumbled onto a 1991 11 years back now. Just a bit over 17000 miles but had been garage parked for right at 20 years. The PO had traded it in on a Hardley who changed the fluids, battery and tires....I still got it cheap. Anyway, I rode it home and around for a few weeks taking notes....stumbled onto this website right after and found some tips. Since I have restored old bikes as a hobby since the mid 1960's I knew what to look for so I ordered the usual suspect parts and pulled the plastic work off. I ended up replacing all of the hoses, vacuum, air, water, oil, fuel. among other things.
Not to make a long story longer but I replaced the timing belt also....experience said I should as time can be a worse enemy than mileage on elastomeric parts. The original part and new OEM Honda spare looked identical, no wear marks or cracks evident and the old one was just as pliable as the new spare. Had I photographed them side by side, I may well have mistaken which was which.
An unrelated to timing belts issue is the original alternator. The original unit has long been out of production and is very difficult to find new. I got lucky and found a spare off a low mile wreck (5000 something miles). It's a lot of work to replace with a later alternator assembly but complete kits are available on Ebay. If you're intent on keeping the bike that may be a good investment.
My 1991 is down right now with an inoperative ignition coil. Got a new set, just waiting on the motivation.
The bike is a smooth runner and very stable on the highway. My wife prefers trips on this bike over our much newer ST1300.