Cool!
I have an oil pressure gauge on both my CB750's. I have always seen that as a not needed item but changed my mind last summer, very hot. Oil viscosity becomes lower and risk to not keep up the pressure in the important bearings when engine becomes really hot, common with flickering warning light at idle.
I see now the pressure direct after cold start 70 PSI at idle, cruising pressure at 4000 rpm on 5:th gear 60 PSI when warmed up, down to 40 PSI when really warm. I'll see in time when oil has degraded and cannot keep up the pressure when warm and time to change it. I can compare how it look like with new oil.
If I should have installed one when I restored and modified my K6 1983-84 I might have seen problems in time when my engine ran really warm and finally blown 2 RC 836 pistons and all 4 rods small-ends became blue, probably due to oil that did not keep up to its the job. Might have killed the oil a few weeks before down in Jugoslavia where the engine ran really warm.
It is better visible down at the oil galley than I thought.
My stock K2 and K6 with billet block
Edit: This made me aware of oil pressure when hot and oil pump upgrade such as new rotors from MessnerMoto. My K6 has a pump with those rotors installed. I noted improvement direct a warm day, oil temp in oil tnak 110*C. Not possible so far to get flickering oil pressure warning at low idle, engine stops before that.
My K2 will get a pump that has new rotors at next service/rebuild. That pump is soaked in oil resting in a plastic bag.
http://forums.sohc4.net/index.php/topic,173081.0.html