Things You'll Need:
- Sheet metal Mallet and pounding bag Metal cutters Rollers
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Step 1
Design your motorcycle gas tank shape and make detailed measurements. Measure the height and width of each side, tracing the shape of the sides, top and bottom onto graph paper in actual size. Be sure to add width for the contours and additional length to each side so they can wrap around and connect together in the front and back.
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Step 2
Cut out the shapes on the graph paper and then tape them to 12-gage steel sheets. Trace around these paper templates with a sharpie marker, adding about 1/4 inch all the way around. Then cut out the shapes with a metal saw.
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Step 3
Dry fit the shapes together to be sure they are exactly what you want. Then add the contours to each side, and the top by laying the metal sheets on top of mallet bag and pounding the contour into the sheet metal with a mallet. You can also use a metal sheet roller to contour the sheet metal.
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Step 4
Run the edges of the sheets through a metal curler to bend the edges. Then dry fit the pieces together.
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Step 5
Weld the two sides together to form the base of the tank. Then weld the top portion to the tank. Use a gas arc welder and be careful to create a perfect bead, because the tank needs to be airtight.
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Step 6
Fit the bottom of the gas tank inside the two side pieces and tack weld it. Then complete your weld with an even bead.
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Step 7
Place your tank hardware onto the tank, including the gas cap fitting, petcock valve and fuel hose. Trace and outline the parts, then cut holes for each into the tank using a drill and metal saw. Fit them securely in the tank with the proper gaskets and a continuous weld.
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Step 8
Place the gas tank onto your frame and make marks for the additional tank hardware that will attach the tank to the frame. Tack weld these fittings onto the motorcycle gas tank, refit the tank to be sure they line up and then make your final welds.
