I have a grey market L1-R26 and need to replace the oil pressure sending unit, but i do not know where it is. This certainly makes replacing it more challenging...LOL.
It should be somewhere on the side of the block,possibly the exhaust side and below the head, It should have a single electic wire going to it, You might be able to trace it back from the oil pressure light. Other than a temp sending unit(if you have one) the oil pressure sender is probably the only thing with an electric wire that would be connected to the side of the block.