As my old friend Roy has mentioned checking that the rocker oil feed banjos have not been dished through over-tightening, may I also point out that the head size of the standard 1/4"BSF screw (#188), used at location H,  is small enough to worsen the problem. It really does not span the top of the banjo sufficiently, concentrating the force in the middle. An improvement can be made (without a lathe, Bev!), by using the 1/4"BSF screws used on some Amal carburettor petrol feed banjos, which have the head size of a 5/16" screw on a 1/4" shank. The load is thus spread over a greater area. I know the washer helps, but it is only soft copper and bends very easily.

Dick