Aluminium Fuel Tank Construction

Last year I developed a split in my fuel tank. This was during a Darwin Motorcycle Club race meet, I ended up riding my son’s Kawasaki for the last race. Wow, what a Rolls Royce of a bike compared to my old machine. I remember hitting a series of square edged holes leading into a fast sweeper and tensing for the hammering but I was pleasantly surprised to find his bike just floated over it, as smooth as! Anyway, I just could not afford a new tank at the time, but I had access to a welder and some sheet-metal equipment and I thought, “well I could afford some time to build a new tank”.

I started off fabricating the base of the tank and had to hand shape the section over the main frame member as it curved in two directions. I welded in a plate to fix the fuel tap to with two blind holes threaded M5.

Underneath, showing seams I used to construct the shape

Shaping the base panel involved a bit of stretching and shrinking plus occasional annealing as aluminium will quickly work harden. Once I was happy that this part sat in place over the frame I looked at starting on the side sections. I made some cardboard templates by wrapping the cardboard around the sides of the plastic tank and trimming this down until it was pretty close. I then used these templates to cut out the aluminium sides. The material I used was 5000 series 1.2 mm thick Aluminium.

Base with sides after initial shaping.

I welded in some aluminium round bar that I drilled and tapped blind holes into for the various mounts. I had to use the radiator cowls to position these accurately.

Shaping the sides took a while and the right hand panel had to have a relief cut and shaped in for the radiator cap.

RH side curved in for Rad cap

I continued to work the sides until I was satisfied with the fit for the cowls and mounts. I then fabricated a top panel using a cardboard template to get the basic cut out shape.

Top Panel taking shape


Taking shape

I purchased a fuel filler neck with a suitable cap from a camping and caravan supply store and welded this into the top plate.

Nearly completed

It was a time consuming project and I would hate to charge someone for the commercial hourly rate. But I enjoyed this sheet metal project. I actually completed an apprenticeship as a Sheet Metal Worker in the early 70’s so the skills were there. But as with any project enthusiasm is the main ingredient. Projects such as this should be tackled one part at a time, this avoids being daunted by the complexity of the task, plus each part completed give satisfaction and inspiration to continue.

I welded the tank with a Fronius AC/DC TIG welder in pulsed arc mode and used 5356 filler rods. When my day job takes up less of my time I would like to hand build an AC Cobra replica. Now that would be a photo story!

Shelby AC Cobra

Shelby AC Cobra (Photo credit: Wikipedia)

Pretty Retro Hey!






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