• The oil pump is not regulated during operation and it will deliver it's entire volume of oil under pressure to the oil filter mount. The oil pump is geared to the pinion shaft and operates faster (increasing oil pressure) or slower (decreasing oil pressure) depending on the revs used. Oil viscosity will affect oil pressure. On cold startup, the oil's viscosity is thicker and this will result in a higher oil pressure but circulation will be restricted somewhat. As the engine warms up, oil gets hot and thinner resulting in higher circulation and a decrease in oil pressure.
• Oil pressure readings are generally taken via the oil pressure switch outlet on the oil filter housing. Although, a gauge can be installed at the oil pump with the proper fittings. Installing a gauge on the rocker boxes won't do much good since the oil transferred from a hydraulic to a gravity and slung fluidity by the time it gets to the rockers. An adapter is usually added at the oil pump housing to split the piping to both the oil pressure regulator and the oil pressure gauge.
• Run the engine to normal operating temperature and check the gauge. At 2,500 RPM, oil pressure will vary between 10-17 psi (69-117 kN/m²). At idle speed, oil pressure will vary between 7-12 psi (48-83 kN/m²). ¹⁾

• The 2013 XR1200X has an oil pressure relief valve Set at 50 psi. The idle oil pressure is 16 - 20 psi and at 2500 rpm it should be 40 - 44 psi. It includes an oil cooler with a thermostat that starts to open at 190ºF (88ºC).
• The oil pump and the head breathers are a new design. The oil pump rotors are driven by the cams, the feed rotor is driven off the front intake cam and the scavenge rotor is driven by the rear exhaust cam. ²⁾

The oil pressure switch (for the oil pressure light) is a pressure actuated diaphragm type on / off switch basically.
The diaphragm is spring loaded and held against its contact point when then engine is not running or the when the oil pressure is too low while running.
With the switch contacts touching, this closes the circuit to the oil pressure light and causes it to light up (with the key on, of course).
When the engine is fired up, oil pressure builds in the oil pump, activates the oil light switch and opens the oil pump check valve (allowing oil to enter the engine)
Oil pressure is sensed by the oil pressure switch. By the time the engine reaches over 1000 to 1200 rpms,
The oil pressure is sufficient to move the oil pressure switch diaphragm completely off it's seat which opens its contact point, breaking the circuit to the oil pressure light and it goes off.

77-85 Engines

The check valve is not a pass through but instead a cartridge type one way check valve operated by a spring loaded cup against a seat pressing at 4-6 PSI.
Oil pressure enters the center of the check valve, lifts the cup against its spring and exits the check valve by pushing around and past the cup and into the engine.
At a point, the cup will float off it's seat up against the spring towards the end of it's travel.

The cup will stay off it's seat and open as long as there is sufficient oil pressure pushing against its spring.
This spring actuates the 4-6 PSI pressure that the pump must overcome.
If there is not enough oil pressure to keep the check valve cup completely or partially off it's seat;
The back pressure from the spring will push the cup toward it's seat, or closed position, equal to the amount of minimum pressure loss from the pump.

Until the seat is fully closed, the remaining oil pressure will still try to push past the cup.
At a point, the pressure from the pump will not be sufficient to completely float the cup off it's seat.
So, the cup will turn sideways a bit only allowing oil to pass it on one side.

This reduction in pressure is also sensed by the oil pressure switch.
When the pressure drops, the diaphragm eases back toward the closed position.
If the pressure is low enough, the contacts will close or partially make contact while closing or intermittently opening and closing.
The oil light will come on or flicker depending on the action of the contacts.