Removing tank dents is one of those ideas that in hindsight seems self-evident. Bolt the tank solidly to a fixture that can't move; fabricate a dozen or so curved, heavy (preferably cast-iron) 'spoon's, rods, and levers. Heavy cast iron so they won't rebound; curved to brace against the center tunnel inside the tank. A solidly bolted immovable fixture so that considerable force can be applied without the tank shifting position. A soft faced mallet (or several) to work the outside of the curved surface while muscling the dent from the inside with a 'spoon'.
I've owned motorcycles since 1968, at least one, and sometimes as many as five (at a time). Gas tanks always seem to have dents where the upper triple tree impacts the tank during a tip-over. There are stops cast into the lower tree to prevent this, but the front forks invariably twist upon hitting the ground, and the upper tree/handlebar hits the tank. That's one universal dent.
Another is when the owner decides to remove the tank. The rear is usually easy, but the front always seems to stick. But the owner can lift the back end, move it about a little, so he knows that the front end will just pop off if he only pulls a little harder...Oops...The front pops free and hits the upper triple tree, leaving another dent...
I have an excellent example of each in front of me...My CL450, which is at present my daily rider...
For a change, I didn't make these dents...they came with the bike, bought used back in '07 from a fastidious owner in Harrisburg PA. I'm loathe to part with it for even a short time to repair, as that would leave me ride-less...
...Maybe this Winter...
