[toofiddy]

The part numbers are 13420-KSC-A10 and 13420-KRN-A10. Are they interchangeable? I have an opportunity to snag some cheap 250R parts and I'm trying to figure out which ones are common.

On a related note, can anyone post a link to what a worn countershaft bearing sounds like? Here's a vid of me riding, take a listen and see if you can hear anything anomalous. I feel like I can hear a background whirring noise, like maybe a bad bearing, but I don't know if it's normal or not.

https://www.youtube.com/watch?v=QMD9rhBiTK0

My bike is experiencing oil migration from the tranny to the engine side. I've just replaced the right crank seal, and I'm debating opening up the left side to do the countershaft bearings. The shaft is super tight and smooth in terms of rotation and radial play, but it moves laterally (along the axis of the shaft, in/out of the case) alot, like maybe over an inch. Is this normal?

[SuperGMC]

It sounds fine to me although I don't know about the countershaft endplay. My '06 250X makes all kinds of funny noises that I just learned to ignore.