Electronic tach I am assuming. You could just get a new electronic tach then that should work just fine.
Something like this.
http://www.jcwhitney.com/sun-super-tach-ii/p2009604.jcwx?filterid=c2124m199j1Just have to make sure it is weather proof.
Otherwise you could check ebay or a bike bone yard but the 92 probably isnt too common yet in those.
The ride IS the adventure. The destination is just to get gas!