Trouble with motor- YZ400f

1 reply to this topic
  • MT400f

Posted July 25, 2013 - 04:42 PM



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?


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  • grayracer513

Posted July 25, 2013 - 06:24 PM


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

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