A few weeks ago, going down a fire road, the bike locked up.  It would restart & click in gear, but wouldn't move.
Dropped it at my private mechanic & he had an incredibly difficult time splitting the cases.
He says that once open, the gears & parts had overheated & gotten so hot, that all the gears had turned black & they were difficult to pry apart.  He thinks there probably wasn't enough oil in the bike, but I've always done my own oil changes & it's always the full quart.
So he believes I should get an entirely new bottom end......being gears & engine cases, plus other bits n pieces.
This would cost $3000, so he suggested a used 2005 bottom end off ebay.  I don't know anything about motors, but is it really completely shot?????  He says it's not worth risking using the old parts as they got so hot & may have warped or something.
Anybody wanna weigh in on this????

It sounds like you are getting some good advice here.    The 3K estimate sure sounds high.

Does he know why it ran so hot.  Oil pump maybe?   Its a waste of time to fix it unless you get to the root cause.

Replacing the bottom end sounds cheaper.    But for that bike, that year, I would say goodbye.

I would have to agree with Mauricedoriss untill you know what caused the prob I wouldn't repair it. Also I am picking up a 07 WR 450 for $3000 running and ready to go. If they can get 3k for the cases then parting out your bike you may get that or more for just the good parts. another option is throw that one back in to one piece just to see if you can get it to run only as a learning game then you may not need to pay the mechanic next time you have a prob....just a thought. Good luck

I agree too. Find one on ebay, otherwise the potential for it to happen again is there. I think your mechanic is right too. It was either low oil, or the oil pump failed. Probably low oil. Maniac