[jeffahart]

Those old saddles don't have sending units. Engine sputter is the gauge, plus a little horse sense on when you filled and how long you've drove on the particular running tank. Just keep them isolated. I drove thousand of miles with my old saddles back in the 80s. Just reach down and flip the fuel petcock when the engine starts to sputter. I recently ditched my old saddles. Had mixed feeling about them for my usage now days.