Making A Motorcycle Fuel Tank

RtwPaul, in a former life, with the tools of the trade. Photo: rtwPaul

Hand-making a one-off motorcycle fuel tank or gas tank can be a formidable feat to accomplish.

Firstly the design raises several questions about what you’re trying to achieve: A certain style to match the bike’s design lines, a certain capacity that is required for where this motorcycle might be ridden, or maybe form over function? I have personally sat and had these very thoughts, over the years building dozens and dozens of gas tanks when I built motorcycles from the ground up, built to my designs and dreams, and often to an idea that the customer would bring into my shop.

Material and its thickness can play a large part in how a gas tank will be made… steel, aluminum, or maybe even copper. There is a need to think ahead, about how the gas tank will be held together.

Welding is the most straightforward process and to make it easier it would seem obvious to reduce those welds to a minimum. Doing this in theory sounds logical, but it then requires you to do more forming work to create the desired shape. Those tools might be as simple as a hammer of a specific shape, size and weight, pounding the material against a sandbag or similar. Once the desired basic shape is there, then more technical tools and machines come into play.

If it’s steel then it’s going to be 16 or 18 gauge and beaten into submission with brute force. If it’s aluminum, then some sooty heat is applied to anneal and soften the material to make the aluminum more pliable and easier to work with and reduce brittleness.

A machine line up in my former shop of my tools of the trade included a shrinker/stretch machine (to do exactly as it describes) and a planishing hammer (hitting rapid tiny blows between two desired radiused steel heads to shape and form very specific areas you are working on, with hearing loss as a byproduct of the process…).

For final smoothing, you need an English wheel. Then you place it on the “buck,” a wooden form you made earlier to help you create that final shape you required.

Like anything, there is more than one way to skin a cat, as the saying goes…

…and this might be the other way, the mass-produced way…safety third, and why does everyone throw it on the floor? So that one guy can keep his job!

Watch and enjoy…