How to Repair Motorcycle Gas Tanks

Repairing your gas tank on a motorcycle is similar to repairing a dent or hole in your car body. There are a few things you need to watch out for, though, simply because this container is going to hold gas, and needs to be airtight and leak proof. You use basically the same products to repair dents and small holes, but you have to be careful how you apply them, and remember that the repair area is going to be in contact with gas. If the hole is too large, it is best to just get a new tank, but for minor dents, and small cracks you can take a few hours and save a few bucks.


1) Remove the gas tank from the bike. Disassemble or remove the fuel valves and completely empty the tank. Inspect the fuel cap for cracks and integrity. Carefully look all around the gas tank for evidence of damage, especially around the welds and edges.

2) Check the tank for leaks. There are few ways to do this. You can simply fill it with water (first covering the hole for the fuel valve) and watch for leaks. Or, you can use an air compressor and pressurize the tank to see if air escapes. You have to completely seal the cap (which should be airtight, but may have small cracks in the gasket) and fuel valve area.

3) Locate the leaks seal them. For small cracks, sand the area clean thoroughly, then and apply bondo. Let dry and then sand again.

4) Repair the dents and scratches. Sand these areas carefully and clean thoroughly with soap and water. Leave a little bit of a scuff in the metal to allow the bondo to stick.

5) Apply bondo to the dents using a plastic scraper. Apply large amounts of bondo so it completely covers the dents and goes over the edges. When the repairs dry, retest your gas tank for leaks.

6) Sand the bondo using a hand sander and heavy 80 grit sand paper. Once you have the bondo sanded to the general shape you want, sand it down to a finer shape using 120 grit sand paper.

7) Apply the primer to your gas tank. Use even strokes and apply several coats until the repairs are totally covered. Primer can be applied very thick to hide smaller divots or imperfections.

Extra tips:

* When applying bondo it is best to apply it in one even stroke, making sure there are no air pockets or lumps in the bondo.

* Mix bondo quickly and only mix as much as you need for each repair since it begins to harden quickly. Large leaks should be repaired by professionals, and tested before use. Leaking gas tanks are definitely unsafe on the road.

For Motorcycle maintenance parts and more check out our sponsor