scully39
CB750 New member
I have a 1974 cb750k which I rebuilt into a café style bike. I have a oil pressure gauge mounted to the oil gallery which shares the oil pressure light. I have found when at idle (900-1k rpms) the oil light comes on and pressure doesn't register until I increase the revs. I replaced the filter and oil (10w-40) and put in a rebuilt and tested oil pump thinking perhaps pump cams were worn. Same problem. I have an aftermarket oil tank and lines with fittings that are 1/4" I.D. i'm thinking they may be too small for the viscosity of the oil and the inflow can't keep up with the pump at idle. If the return and inlet lines were reversed by mistake there would be no pressure at any rpm correct? I'm sure they are on right but I want to cover all bases. Only other thing I can think of is a blocked oil passage but the engine has relatively low miles and was clean inside with no debris in filter after first oil change which was done after only a few hours on the engine.
Any suggestions on what to check will be greatly appreciated. I have a lot of hours into this and would like to finish (if they are ever finished).
Any suggestions on what to check will be greatly appreciated. I have a lot of hours into this and would like to finish (if they are ever finished).