I recently had my bike rebuilt. I got a new crankshaft, high compression piston, valves and springs, and the head got shaved, ported, and polished. I put in 1 quart of oil in the bike. Started it up ran fine oil showed up in the glass after letting it run. About a week later it stopped showing. Changed oil and oil filter, still not showing. I checked the oil pressure screw on the head and no oil was pumping out. Bought a new oil pump, and installed it. Started the bike up and oil started showing in the glass again. After 30 minutes of riding it stopped showing. Changed oil and filter again. Put 1qt back in it as always and it's still not showing in the glass. I still have oil pumping to the oil pressure dress though.