02 wr 426 down for the count. got a q?

I dont post much but i do read on here alot. yesterday I had my 02 wr 426 bite the dust. broken rod, damaged right side case. luckly it didnt hurt anything else. only broke a chunk out of the case right above the gears. some wierd little chamber thet goes to the clutch basket. anyways, does anyone ever sell just a half of the case? my local dealer says i have to by both halves from then. I dont believe it. and can anyone tell me if the yz 426 and wr 426 use the same cases? I almost want to run the case i have because it seems like a obsolete spot.

sorry to say that bikebandit only shows you can get them as a set, but the yz and wr have the same part numbers so the cases are the same. you might want to hit up ebay or search around for a motorcycle junkyard.

I'm pretty sure that the cases are line-bored as a set and are sold that way to avoid shafts being misaligned when the cases go together.

Yup, shafts are line bored, and the deck surface is machined as a set. Look to e-bay...

crud. that figures. who could tell me the porpose of the little camber on the clutch half that is on the top middle. just seems to be there to take up space. that is what was cracked and cant see what it is for.

I don't know exactly what part is broken on your engine case, but maybe you can have it TIG welded?

yeah bring it to a welding shop and as long as its not a critical surface (which doesnt sound like it is) you can have it welded right up for relatively cheap.. or you could ship it to me and I would weld it for free

ill post a pic first and you can tell me what you think.

Gotta be careful welding these things (not top piss on your parade...) If it's adjacent to the crank, it's probably pretty highly stressed. Weld material doesn't have nearly the strength of even cast alloys like A356. Not to mention that there will be no subsequent heat treat. Also, gotta be careful that the cases don't warp as they cool down, or you'll never get them to seal. Post up a pic to help us evaluate.

first time posting pics so lets see if it works.

the cause


this all that broke.


different angle


it's on a mating surface.. tough call

Do you have the broken pieces? If not, that's a heck of a lot of build up. You do need to replace what's broken out. The section is a stiffening "rib" for the crank area to keep the cases tight together. Without it, you won't get good clamp up onthe two screws in the area. They will back out and you will develop oil leaks. If you have the "missing" parts and you can find someone to weld them back in and dress off the case for 50 bucks or so, you really have nothing to lose by trying. If you don't have the missing pieces, or the cost of attempting the repair climbs to more than a benjamin or so, I would wave off and buy a set of cases or an engine on e-bay...


I do have the biggest chunk still. It still fits in okay. I really apreciate all the help. I grew up around two strokes all my life with sleds, banshees and 250's. so the thumper world is green. I think ill take it in with the piece I have and get it done. just sold my yfz 450 duner and looking to get a newer wr 450. this bike is going to a back up. thanks again

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