Here is the oil pressure gauge I made for my SXV. I wanted to retain the switch for the idiot light so I could correlate any anomalous behavior. Not sure if I will use this much beyond initial checkout, however. I have concerns about this diagnostic tool surviving the vibration and heat associated with any long-term use.

Salient features...

3/4" square aluminum bar, 2.25" long.
The oil pressure switch has an M10-1.0 thread.
M10-1.0 banjo bolt (I made one, but a double-hose brake banjo would work).
90-degree brass street elbow to pressure gauge.
1/8" NPT pipe plug (not visible in pics) seals the line-bore. Had a nice small one with an Allen head (like Aprilia uses on the engine cases).
I sealed all the pipe joints with green Loctite (for "sealing welds and porosities").

With 10W60 oil at 45 degrees F, the gauge showed 90 psi while cranking to prime the system. After a minute of running, I saw 75 - 80 psi at idle -- increasing as the engine was revved. With the engine up to operating temperature, my oil pressure is about 35 psi at a 2200-rpm idle.

Although the photo shows a 160-psi gauge with an ABS housing, I used a 200-psi metal gauge on the bike. They both have about 1.5" diameter faces. The 200-psi gauge came from a home improvement store (near the air compressor stuff). It was made in China and costs about $4.00. U.S. makers Wika and Ashcroft sell similar industrial gauges -- about $10 for brass, or $50 for stainless. Wika rates their brass gauges for a maximum temperature of 160 degrees F, and their stainless ones at 212 F.

Wika also recommends only using a gauge to 2/3 of its rated pressure if the pressure is fluctuation. You can go to 3/4 of rated if the pressure is steady. Since normal oil pressure can reach 125 psi, I erred on the safe side with a 200-psi gauge.

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