Piece from magnetic drain plug.....

Any ideas? It is about an 1/8th inch long, and 1/16th tall. Some kind of gear tooth, but I think it is too big to think cam. Top and end edge have some kind of etching lines on them, the two sides are smooth like they have mated. Is this coming from my gears? If so, do I have to remove the engine and crack the case? What happens if I don't? Thanks.


Here is another view.


Thanks for any ideas.

I think it is to small to tell. I would suspect it is from the transmission and you may have a chipped tooth. Should not be serious enough to require a tear down. I would monitor your next oil change and drive through all the gears to make sure the transmission feels right.

Or maybe the kickstarter ....

Was the piece magnetized to the plug when you pulled it out ? If so it is steel. It appears too small to be the whole face of any transmission gear. If it was a tranny gear piece then the bulk of the tooth is still there - no worries. Did this come out of a WR450 ? If it came from a WR450 it looks like the top half of a starter pinwheel gear. You could check this by pulling off the left case cover. Do your woodruff update while you're in there.

Thanks for the responses. It came off of a '98.3 WZ400f.

(1998 WR 400f, YZ timed, with 2003 YZ e-cam)

I am hoping that it is transmission. It was stuck to my magnetic drain plug at my oil change (filter was CLEAN, no other fragments), and I have no problems using all 5 gears.

I did hear a "ratcheting" once last week while riding coming to a stop, and downshifting). I shut it down immediately, then never could get it to replacate the sound.


I had a similar piece come out of my 2000 YZ 426. It was the edge of one of the little things that stick out of the side of the 3-4 gears. They go into a pocket on the other gear. It took over a year of hard riding then 4th gear started to go. I rode it until winter then tore it down. It was caused by a bent shift fork not letting the 2 gears engage all the way. They eventually just rounded off an it would still cruise in fourth. you just could not accelerate hard or it would grind. I am not saying this is your problem. It is just a little chunk of metal. I would not worry to much. Just change your oil a bit more for good measure and go ride. If you have to tear it down it is not to bad. ---Mike

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