The two most common types of motorcycle tank repairs needed are dent and puncture repair, and minor leak repair. The first step in resolving these issues is turning off the tank, removing hoses and electronics that run to the tank, and removing the tank from the motorcycle safely. Almost all motorcycle tank repairs will require you to drain the tank of fuel to prevent fires or other safety issues, so have a container standing by in which you can drain the fuel safely and efficiently. Try to avoid getting gasoline on the tank paint, as this can damage the finish of the tank.
Once the tank has been completely emptied of fuel, let the tank dry with the cap off to allow fumes to escape. Motorcycle tank repairs using a torch cannot be done if any fuel or fumes are present in the tank. While the tank is drying, it may be a wise decision to consult the manufacturer to find out if any recalls have been performed on the tank or other parts on the bike. This step may save you the trouble of having to repair the tank at all. If the manufacturer has not done a recall, inquire about their recommendations for repair methods and products, if applicable.
Some motorcycle tank repairs may require you to do some welding with a torch. If you have never done this before, it is best to either hire a professional or do it yourself under the supervision of someone with a significant amount of experience. Welding is not an easy process, so if you have not done it before, you run the risk of damaging the tank even further. The paint almost always need to be stripped from the affected area to ensure the weld can be done properly, so be sure you are ready for the costs of repainting the tank as well.
Motorcycle tank repairs that involve fixing dents can sometimes be done without removing the tank from the bike at all. A dent puller can be purchased from an auto parts store, and this tool will help the repairer pull out dents from the tank using suction. Smaller dents may need to be filled with putty and then sanded, but larger dents can usually be fixed using the dent puller. A dent puller may leave behind some creases or irregularities, so further repair may be necessary.