Can anyone ID this piece?

This was floating around the motor doing damage after finally lodging between the clutch basket and side case on a 2010 YZ450F with 72 hours on it. With both right side covers off, I don’t see anywhere it could have come from. I don’t have the whole thing apart but wanted to get an idea if anyone might know where this might have originated. I did take the left crankcase cover off and there is some scoring on the rotor where it looks like something was caught between rotor and stator but not sure what, this or something else..? There are two pics below. Thanks



It's tough with pictures like that, but the only thing it vaguely reminds me of is a piece of a locking lug off one of the trans gears.

Yeah, ok that makes sense. Up close it looks like it was once some kind of gear tooth or dog (from manual) but its been chewed up pretty bad. There is a tooth broke off one of the balance shaft gear but its not the right size and must be a result of this one floating around. I don't think I'm very hard on these transmissions but this would be the third time I've had some type of transmission failure on a YZ. :thumbsup:

Edited by sean3239
correct description of damage

Looks about the right size to be the tab off the shift guide plate that bolts over the segment. Had this break on my 09.

May be a little too thick though.

first is it aluminum or iron ?

It's not aluminum

it is not from a gear tooth ,they are black and if, u would be able to shift anymore. look for my posts ,i hand a brocken gear on my yz 450 10 it was the 2end.

there is not many options if it is really iron !? is the engine opened or still in the bike?

make a lager pic of it

A chip off of one edge of one lug out of the three or four on a gear would not prevent it from working in a near normal manner. It would, of course, eventually lead to a much earlier failure of that gear.

I didn't take it apart but the shop that did has said that fifth gear came apart and that resulted in a few other gears, 2nd and 3rd, that also came apart or damaged as well.

yah i was gonna say it looked like a engagement dog from a gear.same thing happened to my zx7, guy i got it from used to do wheelies from fist to second and tore up the dogs. so when I got the bike i was doin a stand up in 2nd and it popped out of gear, pulled it apart and found the 2nd gear cluster was hammered and one of the dogs was in the pan

Exactly what I said in post #2.

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