Help 02 wr426 - Bad engine noise -t/chain,bearing?

9 replies to this topic
  • jplear

Posted October 02, 2002 - 03:16 PM


Last Saturday had good riding day. When I got back start bike to drive off trailer and wash. The engine made a bad grinding chain rattle. Bike seem to run fine. I have check the following but noise is still there
Cams,Cam timing and chain,tensioner,oil change normal.valve clearance ok clutch looks ok. Noise is hard to tell were its coming from Very slight at idle get a little gas and there it is.
best describe as rattle grinding noise related to rpm. pulling in clutch does not change it. Bike is 7 month old oil change every 3rd ride well maintain. Any Ideas.
Please help. Bike starts and idles fine

  • dominator426

Posted October 02, 2002 - 08:19 PM


Your skid plate bolts may have loosened causing it to rattle at certain RPM's...It happened to a WR owner on this site before.

  • jplear

Posted October 03, 2002 - 06:42 AM


all skid plates and guards removed - help its almost the weekend

  • dominator426

Posted October 03, 2002 - 08:17 AM


Could your compression release cable be too tight or binded?

  • Rich_in_Orlando

Posted October 03, 2002 - 08:43 AM


My '99 did something similar a month ago. The main crank bearing had apparently disintegrated. I maintain my bike just like you do. The crankshaft is being rebuilt as I write this. This is the second time it has happened. :)

Don't run the motor until you figure out exactly what is wrong. You could do more damage and it could cost more money if you do. All it takes is about a minute for metal shavings to destroy the oil pump and crankcases.

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  • Brian_in_Long_Beach

Posted October 03, 2002 - 10:02 AM


There is a keyed gear on the earlier bikes - my '99 - that the key wears out and lets the gear rattle. I can't remember the name of the gear & I don't have my manual handy. Do a search on my user name for a post around April of '01 - there's lots of info on the problem & fix.

I hate getting old.... 33 is gonna be a bitch:)


  • Stumpy

Posted October 03, 2002 - 10:35 AM


I had the same symptoms that you are having and it turned out to be a worn out cam chain. It was rubbing the inside of the hole that it goes through and producing lots of tiny aluminum shavings. Luckily, I caught it before it did any real damage. Good luck.

  • rogdrzer

Posted October 03, 2002 - 12:10 PM


could it be a muffler bearing?

  • groundhog

Posted October 03, 2002 - 11:36 PM


Search the YZ forum for counter balance gear noise. Early YZs had a problem with lose keys in that gear. Can be destructive if not fixed quickly.

  • jplear

Posted October 04, 2002 - 02:10 PM


thanks for the help


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