Back in 1989 I was rooting around in the loft storage area of a long-time BMW dealer along with the parts manager, who was a friend of mine. Stepping over frames & engines and other assorted parts, I noticed an odd looking gas tank sitting on one of the heating ducts. This is that tank.

What looked like knee pads in the previous photo were really extensions to the tank. This shop had always been heavily involved in racing, and many years ago they had modified this tank especially for sidecar racing. The modifications were all to add additional fuel capacity. The offset filler neck, vent tube, and large petcock holes were a clue as to what the tank really was though, so I purchased it even though it wasn't cheap.

After several hours of careful cutting with a variety of tools, the original tank emerged into view. This is an original BMW RS54 (Rennsport) racing tank.

The left side was obviously where the sidecar racing modifications were started. Dozens of large and small holes were drilled to allow fuel to flow in and out of the additional space - the smaller ones were even done in a precise symmetrical pattern.

The left side must have taken a lot longer than the shop planned, because when it came time to do the right side, a simpler approach was taken! Yikes! At this point the metal work it needed was far beyond my capabilities, so I gave the tank to a specialist to restore for me.

The metal man cut the tunnel out of the tank, and worked all the dents out. He then went about closing up the holes. The large opening in the previous photo is seen here, welded closed with new metal.

Here is a view of the tank with all the holes closed up, and it's ready to go back together. The tunnel section is seen laying to the right of the tank. The two pieces of metal inside the tunnel are the left and right baffles inside the tank.

Fast forward about 10 years (yes some of these projects can take a long time!) and you see the same tank, completely finished and mounted up to my racer.

Just in case you really have to have an RS tank of your own, check out The Tank Shop, since they are making an aluminum reproduction. Look for their Racing section to read more about it and to look at more photos of the tank.

While not a "custom tank", I thought you'd enjoy the interesting blend of cultures portrayed by the paint work!