I heard there were 3 recalls on '88, '89, and '90 Exciters all regarding the fuel system. *Does anyone know anything about these, or can anyone tell me where I could find out this information?

Try doing a search on it. I have heard something about the carbs being recalled too but nothing else. Maybe try posting in general to get some attention.

Yamaha updated the carbs on the 87 Exciter from butterfly Mic. to the 38mm round slides Mic. with a power jet.
88 Exciter came stock with the 38mm round slide with power-jets
The 88's had a update to plug off the power-jet and rejet the main.
I think PSI was the first to find the problem, and it was a mid range lean spot from the needles.