Saving a '81 KZ750-E

Elation turned to frustration overnight. The pressure build up should have made me more cautious. Last night it got enough to bend my tank! The underside rib ballooned outward, and the two sides of the tank splayed outward. This caused a dent to form on the top, just in front of the filler neck. This tank had no dents or dings. Now I'm not sure I can straighten out. So very bummed...


The two bottom surfaces were flat and parallel to eachother. Now they are splayed open.

Along with the damage from the pressure build up, a leak formed at the rear mount bracket. It is spot welded onto the tank, but there is a rust pin hole between the tank and the spot welded bracket. So yeah... a rabbit hole indeed!

Holding the tank in my lap and using a dead blow hammer, I managed to get the bulged out center rib back close to the original position. Some of the dent relieved on the top of the tank, but not entirely. The tank is no longer a symmetrical shape, and no longer sits flat on the table or floor. Man, the air in my shop is blue right now! Wonder if my neighbors here my swearing rants right now...

Arrgh, that sucks:S :S :S but nothing you can´t handle. Good work so far, move Forward....

The tank is drying with the heat gun, and I am starting to get my blood pressure back down. The small dent on the top can easily be corrected with body filler. I am considering having a welder TIG weld the entire perimeter of that mount bracket to seal the leak. I really don't want to drill out the spot welds to get to the area where the leak is, that will just create more weld repair work. Moving back into repair mode instead throwing wrenches mode...

When the tank is dry, the plugs will go back in and I'll get the entire outside bead blasted clean.

The dent on the top.

I pulled the heat gun, and the entire inside surface of the tank is now orange with flash rust. I was hoping drying the water rinse with heat right away would be okay. I didn't rinse with WD40 since I haven't confirmed it would be okay with the paint process and not bleed out ruining the paint. One fix leads to another repair process. Can't seem to catch a break today.

Bore scope shots

I've experienced a similar snafu with a tank before. To bring the edges in I traced out the hem flange pattern on some wood, used a flat blade screwdriver to pound the board and create the groove, nested the tank on the boards, then used a mini sledge to pound the board on one side, while supporting the other side against a wall, until the tank was back in shape.

I was going to mention something about not allowing pressure to build up in the tank but your comment previously seemed to suggest you were aware. Anyway, we learn from mistakes so time to learn...

The metal sleeve at the filler hole is leaning way off center now.

The bore scope has revealed some additional black "tar" areas still in there. The Cleaner/Degreaser did a good job, but apparently not 100%. Since it calls to dilute it 4:1 with hot water, I still have some unused left over. I wonder if I should use less hot water for a stronger solution. I can't seem to get the scope in the right position to see the area under the mount bracket though.