Brought my GT80 out of the barn and into the garage for some TLC on the lift.
Eww.. Yuck..
Let the games begin. We all know the routine….
imgur.com/a/iwqTmZ7

Wow, inside of that tank looks terrible! What happened? Ethanol gas sitting for a long time?

YUCK!

I cleaned a '71 175 gas tank that looked like that. I used apple cider vinegar. It developed pin holes. Had to line it with 2 coats of POR-15. But the original paint was saved.

No, I don’t use ethanol gas. My theory is that this little 80 is the first bike in my row of bikes inside my barn. It has a window next to it, and I think the sunshine’s onto the tank in the cold temp’s and creates condensation. I try to keep all my tanks topped off to the rim, but this little 80 gets ridden more than any of my other bikes. So it was not topped off.  The bottom of the tank appears to be pretty clean, so I am hopeful that it will clean up without pin holes.

imgur.com/a/nu71fGw

Wow, nice lineup there. Shame about the tank. Hope it cleans up without holes.

Tank cleaned up with no issues, disassembled the carb and petcock, put them thru several cycles in the ultrasonic cleaner and it runs perfect.
Then I checked all the tanks and they are all good. So I put a cover on the 80 for now but may hang some form of curtain to block the sun.
imgur.com/a/Wd735hN