Friday, March 6, 2015

How to pressure test a motorcycle gas tank

If you just purchased a new gas tank for your motorcycle, customized your existing gas tank, or added a fuel sight gauge it is imperative that you pressure test your gas tank to be sure there are no leaks before you line, prep, and paint the gas tank. Whenever we weld on a gas tank we pressure test that tank to avoid any costly reworks after the tank is painted.
  1. Plug all openings in gas tank
  2. Pressurize gas tank to 5-10 psi
  3. Submerge gas tank in water
  4. Note any bubbles and mark tank if any leak
  5. Repair tank and retest
  6. Clear any water from raw tank

1. Use a non-vented gas cap or we often use a Fernco rubber plumbing cap (available at any plumbing or hardware store) to plug your gas tank fill hole. The Fernco QC-102 is a 2" Qwik Cap that works perfectly for peanut tanks with a cam style cap bung. We use a non-vented cap or a plumbing compression drain plug for threaded caps. If there are any crossover fittings or fuel sight gauge fittings plug these with pipe fitting caps. Use the remaining petcock fitting to install a petcock.

2. Fill the tank with air. We use a hand pump to reach the necessary 5-10 psi. I suggest that you do not use compressed air to fill the tank as it is difficult to control the volume of air going into the tank. Do not exceed 10 psi as deformation can occur or seams may split. I have seen this happen and you will have a lot of work to do to fix the issues.

3. Close the petcock to keep pressure in the tank. Submerge the tank completely in a tub of water. We use a Rubbermaid container, but I have heard of people using bathtubs, laundry basins, kids' pools, etc.

4. Any bubbles that are consistently coming out of the tank indicate a leak. Look very closely at any potential leaks and mark them with a paint marker or permanent marker. Sometimes these bubbles can be difficult to see where they are originating from, so be sure that you are finding the original source of any leak.

5. Dry your tank off with some compressed air and repair any leak in the tank. You will need to weld or solder the leaks as necessary. Do not rely on your tank liner to repair pinholes and leaks. Be sure to pressure test again after any repairs.

6. When your tank is consistently holding pressure and you have no bubbles, you can rest assured that your tank is ready to be lined with a good tank liner.

-Steve Rullo

Visit our How-To section on for other informative articles.


  1. There are numerous substantial reasons why you have to contract an expert handyman to play out any gas fitting administrations that you require for your home or business. plumber Glenfield

  2. Are you in the market for a motorcycle, but have bad credit and need a high risk motorcycle loan? calgary car transport

  3. You should be well familiar with the concept that changing your oil within the recommended guidelines is the single best thing you can do for any engine on any kind of vehicle. This obviously includes motorcycles.motorcycle shipping

  4. Take a gander at your handyman as an advisor who can make sense of the issue, give you a general thought on to what extent it will take to settle it, and give a precise

  5. Interesting post. I have been wondering about this issue, so thanks for posting. Pretty cool post. It's really very nice and useful post. stainless steel foundry