Sometimes I am amazed at what I find when working on peoples bikes. The other day I was working on a 73 Honda CB750K and when I removed the oil filter there it was. Who ever had last replaced the oil filter either didn’t note the order in which they removed it or doesn’t care. They had reversed the filter/washer /spring and installed them backwards. Below is the correct way to assemble most Honda CB element style filters.
Instead of the spring/washer pushing the filter against the motor insuring the oil travels through the filter and pressure valve it was holding the filter away from the flange allowing the oil to completely miss the filter and I don’t think that helps the oil pressure much either and that’s bad. I sure hope it was not a shop that did that. This is a very common mistake I see all the time. If you do your own maintenance, READ THE SERVICE MANUAL or the money you save will be spent fixing the damage ignorance caused.