Engine oil pressure specs

Does anyone have the engine oil pressure specifications for the 1982 XJ650RJC they could share? I’ll even settle for sober and well considered oil pressure numbers from one of the many, ageless XJ gurus found among these forums.

I cannot find any oil pressure specs anywhere. I’ve checked both the factory and Clymer manual several times and can find nothing. I even asked my wife and she had no idea (another mystery for another time).

I find this damn weird because I have many other bikes with many other manuals and they all list an engine oil pressure spec of some sort.

So either I’ve gone half blind and can no longer read a service manual or XJ650 engines have no oil pressure to begin with, thus rendering the listing of this spec somewhat, er, um, pointless?
A curious engine set-up, but at least you won’t waste any Hp pumping that damned oil around, well for the first while at least

As always, any help is greatly appreciated,

 

OIL PRESSURE GAUGE:

The part that Yamaha forgot. In almost all high-performance engine settings, the measurement and knowledge of operating oil pressure is a vital part of operator information. These following kits allow you to monitor the engine oil pressure on a periodic or continuous basis, allowing you to monitor critical internal engine conditions.

These engine OIL PRESSURE MEASURING KITS contains everything you’ll need to take periodic measurements of the engine oil pressure………something that Yamaha never provided a means to do, for some unknown reason(s). Periodically measuring the oil pressure in the your engine can provide clues as to the health of various engine components (not just the oil pump condition, but more importantly, bearing clearances….as excessive bearing clearances will “leak” pressurized oil and reduce oil pressure, thus leading to all sorts of problems). Thus keeping track of oil pressures over time is an important “maintenance” procedure, akin to checking cylinder compression pressure periodically.

This kit contain a specially made main oil gallery plug and a liquid-filled mini oil pressure gauge. The gallery plug replaces the left side factory gallery plug ----- the one directly below the left crankshaft end cover (which was actually called an “oil pump cover" by Yamaha, for some odd reason……). Once installed, you can run the engine and check oil pressures at various engine temps, and record the readings. Although you can leave the gauge installed permanently, we do not recommend this, as it does stick out past the pump cover and you risk damage of epic proportions if anything were to disturb it…….

Each kit comes with block-off plug, so that the gauge assembly can be removed while leaving the gallery plug in place; then, the block-off plug replaces the gauge assembly and creates a leak-proof solution, while leaving the gallery plug in place, ready to re-use (re-installation of the gauge) whenever is necessary.

And although Yamaha does not specify oil pressures for their engines, they do note that the oil pump relief valve is set to open at 64-78 psi, so you can use that as a guide.