I got nothing for the intermittent running.. One of the more experienced guys (QWERTY) should be able to help you trouble shoot...
Tank can easily be sanded and painted over.. Many options on upgrading to a larger tank.
Turn the petcock off after riding and that should take care of the smell.
Wiring diagrams are available in the tech manual.. sticky in this forum I believe as far as downloading it.
Sand and paint any rust..
I paid $650 for my 91 and think I should have gotten it lower for all the issues I've had to fix... But, I guess that's the charm of owning a 20 year old bike, you can do whatever you want to it to make it yours. I'll keep mine until the motor dies I like riding it so much !