Hi, I'm new here and have a question. I have an 81 XR500R. At the last oil change I noticed a large amount of metal in the oil. I took the engine apart and rebuilt it. It still made metal. I took it out and installed a different engine and this one is also making metal. Neither engine makes any noise and they ran great. Could this be a faulty oil pump? The first engine when, I tore it down had a bad cam journal so I thought that was it. However after thinking about it I thought there was way to much metal in the oil to be just the cam journal. Anyone else have this problem? Thanks.