Trouble with motor- YZ400f


I recently bought a 1998 400f from a guy who couldn't get it to run. A quick carb clean and rebuild and some gas made it run great. I put probably about six hours on it after that.

On my last ride I started it and was riding for about 30 seconds and just as I was getting ready to stop and check the oil it sort of bogged like I had forgotten to turn on the gas. It died and then started a few times before seeming to seize up (kick start was rigid). There was plenty of oil and coolant.

The motor will turn over with a socket on the crankshaft, albeit not smoothly and with a grinding/scraping noise. I drained the oil and there were significant metal shavings in the oil filter housing. I popped off the valve cover and the camchain seemed to be intact.

I believe the bottom end is okay (can turn back wheel over by hand in all gears with clutch lever in).

I know I need to start opening it up and getting to the bottom of it but do these symptoms indicate anything in particular to look for?



No, nothing in particular. Check the condition of the oil pump while you're there, though.

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