Stretched Gas Tank: How To Stretch A Motorcycle Gas Tank In 5 Steps!

If you want a stretched gas tank and you have some basic welding skills, you can easily stretch a tank for your chopper making it as unique as your imagination and skills can take you. Keep in mind this is just a guide; you should be sure you are able to do these steps and understand them before you begin.

Stretched Gas Tank Step 1:

The first thing you should do when installing a custom gas tank is to make sure your new tank is completely devoid of fuel. You will need to do some welding and you do not want to have any fuel left for safety sake. You should also gather your materials so you have everything ready to stretch a gas tank. You will need the following:

  • Cardboard
  • Shears
  • Welder - this can be rented if you do not have your own
  • Sheet metal, 20 gauge
  • Primer
  • Caulk
  • Bondo
  • Sand paper
  • Tank Sealant
  • Sealant
stretched gas tank

Stretched Gas Tank Step 2:

Make the pattern for your extension out of the cardboard then trace it onto the sheet metal. Cut the pattern out of the sheet metal then form it to make the gas tank. Use the marker to create lines to line everything up. Before you begin welding, be sure to remove the old paint from the gas tank using sandpaper or a grinder.

Stretched A Motorcycle Gas Tank Step 3:

Tack weld the middle of the extension to the marked center on the gas tank and move around at approximately one inch intervals until it is complete. Try to make sure the sheet metal is flush with the old tank. Once complete, let it cool completely then sand down the weld spots so everything is even. Use the shears to even out any edges so that it flows completely with the tank.  After you have everything smooth, mark a line where the seat will go and then trim any excess. 

Stretched Gas Tank Step 4:

Use the caulk to fill in the space between the extension and the gas tank.  Make sure you use all weather caulk so it holds up. Then, clean the entire unit so there is no excess caulk. Bondo is perfect for filling in the seams, ensuring everything is flush. Once again, sand everything so it is smooth and clean it thoroughly.

Stretched Gas Tank Step 5:

The final step in the process of stretching a gas tank is sealing. You want to make sure your tank extension doesn't leak. There are a number of tank sealers available on the market. Typically, you pour in the product and keep it moving and rotating to allow the product to completely coat the inside of the tank. This procedure will not only prevent leaks but will keep rust and corrosion from forming inside of the tank. This is good for longevity as well as keeping your entire fuel system working properly.