This is the second time this has happened. My ZR smokes a lot, more than other sleds. I always use more oil that the other guys I ride with. A couple years back I took it in and they replaced the oil check valves. That did seem to do the trick for a couple years but now it's back. It was a little pricey to get those changed so I'm thinking about doing it myself but first I need to understand how this works. My knowledge of a check valve is that by design they just stop fluid from going the wrong way. How does this effect oil usage?
I have checked and according to the service manual the marks for idle and max throttle do line up.