Check the wiring at the horn contact, if good, jump the horn with another battery to see if they do indeed work. If they do, then the problem is with the contact button. Take it from there.
10w40 will do just fine. I use Motul.
On the right side there is a chcek glass it is hard to see
I have a 1982 GW 1100 Interstate 20 90 18 front Michelin mu90 b16 78H rear Dunlap
1980 was the first new version of the Goldwing Interstate. It came with the 1100 engine. That lasted till 1983, then the "84's came out with the 1200, good till 1987, then the 1500's. The 1980 Interstate all dressed cost me just $ 5,000.00 here in Canada, those were the day's.
The best way would be to pick up a manual. Just too many things to do.
The standard comes with no extra equipment, fairing or side bags. The interstate is a full dress right from Honda.
go to: www.goldwingdocs.com
No
Should be just beside the battery.
Water cooled.
Iraqi the front of the engine at the bottom
Look for the ID tag on the frame head. They all start with GL then the engin size (1000, 1100, 1200, 1500 or 1800) then there may be a letter, I for Interstate, A for Aspencade and S for SE (Special Edition).