Rebuild question!

Hey all, new here to the forums- found this researching my situation on Google, I think I've found my new internet home. I tried looking for some pics of the cases on the forums but no real luck finding the parts in question... I'm currently rebuilding my 01 yz250, the crank bearings (and I'm sure some other contributing factors) went out and destroyed everything from the crank up, including the jug. The top end is brand new and ready to rock but when installing my Wiseco bottom end, two parts fell out of the case when pressing in the new bearings- I can't seem to find them on any of the parts fiches in my manual(s) and I was hoping someone knew where I could find them a home!


These both fit perfectly around the shaft with the o-ring that the front sprocket later mounts on, but this can't be their proper place as the case will not seat with that spacer on there. Any help is greatly appreciated! Thank you!

The first thing I thought when I saw the picture was countershaft. If you take a look, the seal on the countershaft does not actually seat against the countershaft itself. There is a collar that goes over the shaft, into the seal. You put this in after the case is together.

It one side of that collar sort of conical?

25 is the seal, 26 is the collar. Not sure on the washer.

Hey Puma, thanks for the input man, but the countershaft sprocket's spacer is already accounted for, which is why I'm so confused here. The internal diameter is the same as the spacer you mentioned but the thickness of the spacer in question is about double that of the countershaft's spacer (#26). I also noticed that there is a perfect wear mark on spacer-X and both sides (left and right, internal and external) are conical. :smirk: That thrust washer looks pretty at home behind the clutch basket.


I believe the thrust washer is the washer that goes behind the clutch basket. My manual says it is 42mm (1.65in) diameter.

The spacer looks like it goes around the end of the crank on the clutch side, underneath the primary driven and drive gears.

I have my bottom end split currently, and my primary drive gear spacer has the same wear pattern your picture shows.

Makes sense to me, GMO, thanks! That's where the pictured washer belongs. Still can't quite picture how this spacer goes in, is there any way I could get a photo of it? It's not covered in my manual apparently, or there's no illustrations at least.

Yeah, I checked my manual for it, and I could not find any pictures either. Seems this was left out.

The spacer slides over the right hand side of the crank. When it slides in, it will slide inside the crank seal.

It goes on after the cases are pressed together. On the outside of the right case half.

GMO397 is right. I recently rebuilt my CR250 and that's were it went for me. I didn't want to post because I wasn't sure since mine was a honda.

Crap. The first seal I installed was too big to seal to the crankshaft so I switched it for another smaller seal, the spacer doesn't seem to want to slide over the crank any further than the teeth for the drive gear? :smirk:





Dug out the old crank, pictured right. The teeth run the distance of the spacer (0.75in) further back on the crankshaft, have you gents ever had experience with the Wiseco cranks? It says it's for this model, year, etc, and the smaller oil seal I have on now snugs up to the crankshaft perfectly. Maybe they did away with the metal spacer and just rely on the bearing for support as with the stator side? I'll have to call Wiseco and see if that's the case, or a packing error. Thanks for all the help guys, you rule. I will follow up as soon as I get an answer. :smirk:

My wiseco crank resembles the one on the left more accurately.

I have no problems sliding the spacer on the crank, give them a call, something is off.

In the works, tried calling yesterday morning and the message said they were closed, I'll try again tomorrow and post what they say.

Hey, I just re read my earlier post. My wiseco crank looks like the one on the right.

The plot thickens. Tried calling Wiseco again today with no luck, they must have some weird business hours, 9am EST and they still haven't turned on the phones? :smirk: Must be nice!

OKAY It's a few months later and with sufficent riding and paranoid checking of the crank, I have come up with this: Check your VIN number and crank design before you order parts, I have a half year model, so while it's an "01" the engine is an "00," however I haven't had any problems with fitment of other parts. My fix: I had to shim behind the basket with an extra washer I had laying around (the largest of the washers on the parts fiche for this section of the engine) and it didn't fit around the crank perfectly (about 1mm of play in it) but it does the job nicely, I haven't observed any premature wear with 20+ hard trail hours on it, so I'd go ahead and say that's a safe fix if this ever happens to you. Hope this helps the next poor soul, if you guys have any further questions please go ahead and get ahold of me.

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