I have just made an oil pressure fitting for my 550. It is a commercial M20 x 1.5 steel plug tapped in the middle M10. The banjo bolt is std M10 hex head screw drilled for the oil. The banjo was turned from brass and had a std steel 1/8 BSP fitting turned down and silver soldered in place at an angle to route the pipe up between the engine and gear box. The pipe then goes over the top of the gear box and up the LH frame tube to the front of the bike.
I bled the oil pump by removing the oil pressure switch after trying various other methods and the oil instantly showed itself. Replaced the switch and then spun the motor (plugs out) on the starter and the gauge showed about 55 PSI.
Oh yes the whole lot was finished off with some zinc plating.
