Vibration at decent throttle and dash not working

[JustBought]

Ok I have been riding for a few years now and decided to buy a 1984 GL1200. I am new to bikes this old and goldwing in general (yes the noises of an old goldwing that says it has 91,789 for sure miles has me paranoid), but I'm the kind of person to keep old stuff on the road. I know why my Speedo dont work (plastic peice on the front wheel is broke where the cable holds in place),but the rest of the dash goes in and out here and there.So the question is where should I start looking for that issue as I wanted to consult the goldwing gods before tearing into the dash. Second, while riding, if you give her a good amount of throttle she vibrates decently but not terrible. Also vibrates a little when I let off throttle without pulling in clutch. I can not tell where it is comming from. Any help would he greatly appreciated!