Article By: Daniel Donley – Pandemonium Custom Choppers – www.pandemoniumc2.com
Originally Published In The September 2012 Issue Of Cycle Source Magazine
Working on a custom build? Just want to freshen up the look of your current bike? Well this month I am going to show you how to mount a Frisco styled gas tank. I’ll also be showing you how to relocate the petcock so you can get a few extra miles out of that small, but cool looking gas tank.
When getting started on mounting any gas tank, you first want to set it on the bike and figure out where you want it and what looks the best. Don’t forget to check the handlebar and controls for clearance of the tank.
I always mount the front of the tank first. Start by making a mark with a Sharpie, and then center punch the mark.
Next, use a center drill to start a pilot hole; a very small drill bit will also work here.
Using a step drill, drill the hole to the desired size to fit the bung. I like to use stepped bungs so they set on top of the backbone and are a lot easier to keep straight while you’re welding them.
Be sure to use Anti-seize on the threads of the fasteners to prevent them from getting stuck while you’re welding in the bung.
Now, the front of the tank is located and tacked into place.
Mark and repeat the process to the rear mount.
For this tank, the mounting tongues are slightly rounded. With the bungs fully welded to the frame, round the tops of the bungs to fit the contour of the tank with a grinder.
Now that the gas tank is mounted to the frame, time to move on to relocating the petcock to utilize all the fuel in the tank.
Drill out the existing petcock bung using a hole saw, and then de-burr the hole with a file.
Cut a small circle from a piece of sheet metal to fill the old petcock location and weld into place.
Drill the rear of the tank using your step drill and fit your new petcock bung into place. Common sizes for these are ¼” NPT and/ or 3/8” NPT, but be sure to size according to your petcock.
Now that you have all of the fab work done on your gas tank, be sure to pressure test it. I normally test pressure at 3 to 5 psi, no more than that. You don’t want to turn your way cool new tank into a bomb, so be careful here! This is a project that can easily be done in a few hours. It only requires basic fabrication skills to make the stance of your ride look even cooler and also be beneficial to utilize all of the fuel in your tank.