`Had the `71/750 engine rebuilt over the winter: new rings, bearings/superblends, rebalanced crank, overhauled the head/valves/guides, etc, etc, and have 850 miles on it ...now a running high-zinc conventional 20/50 after break-in. (I removed the old (non-regulated) oil cooler off as part of the larger bike rebuild at the same time. ) Prior to this, the right cylinder had begun burning through about a cup of oil every 100 miles... probably valve guides.
Now runs/performs well, no smoke or oil-burning/oil-loss (also etc, etc.). Does NOT wet sump even after two weeks of idleness/recovering from minor abdomonal surgery before I could start it again. I therefore assume the oil pump/gears/plates assembly is reasonably "tight."
But....
I've always had a Sun oil pressure gauge that I mounted way back in`73 picking off the banjo bolt in the head which feeds the rockers. Before the rebuild, pressure with 20/50 GTX was at least 35-38psi @ 3,500 RPM/hot, and 20-ish psi @ idle.
NOW the indicated oil pressure using that same 20/50 dino oil is ~18-19 psi @ 4,000 RPM/hot, and only 6-7 psi idle/hot. Oil temp in the tank/hot is 210+-ish (no oil cooler). I'm going to pull/replace the oil pressure gauge/pick-off line tomorrow to double-check that I don't have a bad instrument (even though I don't think that's the problem).
Any other thoughts/ideas as to either the pressure, or the "don't-worry-about-it-because-it's-oil-flow-that counts" school of thought?
Now runs/performs well, no smoke or oil-burning/oil-loss (also etc, etc.). Does NOT wet sump even after two weeks of idleness/recovering from minor abdomonal surgery before I could start it again. I therefore assume the oil pump/gears/plates assembly is reasonably "tight."
But....
I've always had a Sun oil pressure gauge that I mounted way back in`73 picking off the banjo bolt in the head which feeds the rockers. Before the rebuild, pressure with 20/50 GTX was at least 35-38psi @ 3,500 RPM/hot, and 20-ish psi @ idle.
NOW the indicated oil pressure using that same 20/50 dino oil is ~18-19 psi @ 4,000 RPM/hot, and only 6-7 psi idle/hot. Oil temp in the tank/hot is 210+-ish (no oil cooler). I'm going to pull/replace the oil pressure gauge/pick-off line tomorrow to double-check that I don't have a bad instrument (even though I don't think that's the problem).
Any other thoughts/ideas as to either the pressure, or the "don't-worry-about-it-because-it's-oil-flow-that counts" school of thought?