Using a new early CB tank (take-off on sidewall), with a later RB sender unit (take-off through the unit), to give me an inlet and outlet, in case I decide to use my fuel injection.
I cut out the entire recess on the sender side of the tank, cut out the sender unit retainer and sidewall take-off point from the removed plate. With a hole that size it is also an ideal time to fit a swirl pot, before re-welding a single replacement panel as pictured below. Welding the baffle in place from this angle is very difficult, so I decided to cut an extra 9 inch hole in the top to ease the problem. If a carburetor version only is required, cut out the sender unit retainer ring only, leaving a smaller repair and no swirl pot.
I then used a 60mm cutter to make the hole in the front face of the tank; there is an ideal area central on that side. Re-welded the sender unit retainer in its new position with old sidewall take off point nearby.
Pressure testing the tank is simple, attach a balloon or in this case latex glove to the filler neck, block off one of the inlets if fitted, and attach a pipe with valve to the other. Inflate and wait and see. I had to have two pin-holes welded up, which is not bad considering I also shortened the tank at the same time to clear my axle.
Finished product, just needs etch priming and painting!
