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'03-?? '13? WR250F Flywheel and Starter Gear Compatibility?

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Does anyone know if a newer flywheel/starter gear/starter clutch(bearing) will fit a 2003 WR250F?  I see that they changed the design some through the years, but I suspect that if I got everything from the crank thrust washer out that it would interchange just fine.

It looks like the whole one-way bearing design changed in '04, which I'm not against as I believe that's what ultimately caused my failure.  The rotor stays the same through '13.  It looks like they added an actual thrust washer between the ring gear and the rotor in '06 (and I assume shortened the snout on the ring gear by that amount, thus the new p/n) and otherwise everything is the same through '13.

I guess based on the above, I would assume everything from '04-'13 is swapable in the correct combinations, so my real question is if the change from '03-'04 made anything incompatible.  Given that the stator itself is the same for '03 and '04, as is the intermediate starter gear that the ring gear meshes with, and although the crank shows a different part number aftermarket pieces are listed as '03+, I'm fairly certain it's a go.  But verification from someone who knows never hurts.  Not having to find one year specific parts would sure make things easier.  Thanks!

Edited by Gimper

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In case anyone is interested in the failure that brings the topic up, attached are a few pictures.  I believe that the starter clutch began binding, which given the off center single point contact of the intermediate starter gear put an axial twisting force onto the starter ring gear.  Even though the crank runout was within spec, it would seem that the added pressure caused the needle bearing to wear on the high spots on the crank (opposing sides radially, opposing edges axially).

I don't recall what the actual crank runout was, but it was within spec, though at the high end.  Given that it was an aftermarket crank (no recollection of what brand though---it's been 5 years since I put it in), that seems pretty standard from what I've read.  I'll be checking my new crank before installing it.

Note the flat spots on the one-way bearing rollers!  Also the crescent wear on the back of the flywheel, which also indicates to me that the crank had enough runout for the rotor to be off-axis enough to wear like that.

I quit riding it when it I noticed while warming it up before a ride that it sounded totally normal, but a significantly louder than usual.  No crazy knocking or anything, just the usual bearing growl, but noisier.  I figured I was going to find main bearings that were shot.  In the end it was a stroke of luck, as I found that one of the third gear dogs was cracked the entire way around and must be hanging on by a sliver of intact metal in the middle.  I could've been one ride from a total transmission grenade for all I know!  (Video of cracked dog)





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Well I decided to take the plunge and purchased what looks like a very clean 2009 setup on fleabay.  Unfortunately it's missing the thrust washer between the starter gear and the rotor, so I'll be adding that to my OEM parts order ($5 for a washer!), though it does have the one between the gear and the crank.  It's also missing the needle bearing, and I'm going to my local bearing supplier on Monday to get as many bearings as possible rather than pay double for OEM; does anybody happen to know the bearing manufacturer's part number for this needle bearing?  I'll order the OEM part if not, but again, it's $15 and probably only 8 from a bearing house.  I try pretty hard not to be too cheap these days, but $5+ bucks a bearing adds up when you have 10+ to buy.

In any case, I'll report back when I know for sure that it all works, but I'm fairly certain at this point that it will.

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