Topic: Dry Rust

[muzzy]

My CB750 has a very fine /dust rust inside the top of the tank, Its only where the fuel level has not reached.
I have removed the tank and sloshed fuel around I cant see any discoloration or sign of the rust coming off.
The rest of the tank is perfect only area is the very top of the tank that doesn't see fuel.
Any comments or suggestions much appreciated
Regards

[pjlogue]

I would put in a quart of rust remover, seal up the tank and slosh it around leaving the tank upside down for a few hours then check it.  Once all the rust has been dissolved I would flush it out with clean water 3x and do a final rinse with distilled water and then an Acetone rinse being very careful to not get any Acetone on the paint!  Put the tank back in service and refill with fresh gas ASAP.  Acetone is hygroscopic and will suck moisture from the air so refilling with fresh gas quickly is important. 

-P.