Yes, there must be a hardened washer at each end of the splines or the spline ends are at risk of galling or blueing. One washer is usually slightly thicker than the other.

Endplay should be very tiny or zero if you go on manufactory recommendations for a angular contact ball bearing. A angular contact bearing was fitted original on the clutch side. But if you use an ordinary ball bearing instead, the mainshaft endplay is not that important as long as it exists, I would recommend to keep it between 0,1-0,5mm 0.005-0.020 inch. A tiny tick tock if you go by ear...

Because of the weak 10mm bearing on the sprocket side and violent forces the chain will put on that bearing, the bearing will not keep its axial stability very long. When that thin bearing is worn a little, the mainshaft will have a larger sideplay than originally set, and the angular contact bearing on the clutch side will loose its settings and its up-and-down play becomes exponentially larger. That in turn can cause clutch cage wobble and transmission dissonant sound.

A regular 6207 2RS (double rubber sealed) bearing of good quality and presicion on the clutch side will keep the up-and-down play a lot smaller than with a angular contact bearing when the mainshaft becomes looser. A good quality bearing will hold up fine for the axial force you will put on it when you operate the clutch. The wear is kept down if you use a 2RS bearing that is shielded from the dirty and metal flaked oil that will be present in the gearbox. Don't remove the shields. You can rely on that it is lubricated from factory for life.

Ok, back to the distance washers on the mainshaft. Maybe following info is nitpicking, redundant and supplementary but anyhow..

Depending on what side you put the thicker washer, you shift the mainshaft a tad out or in.

So, depending on how you shim the mainshaft, a mainshaft ledge is putroting past the sprocket gear end. In turn the ratchet spring washer (original hardened) is riding on that ledge -or- dragging on the sprocket gear. It may matter for the ratchet noice and preventing kicklever return when you start the bike, if the washer is dragging on the gear instead of riding on the ledge. In my opinion the washer should ride on the ledge. However, a soft unhardened spring washer will wear down fast and start drag on the gear.

Remember to regulary drip a drop or two of oil through the tiny oil hole in the chainguard to lube the kicker mechanism. Oil splatter from the chain will not reach that.

If you check the albums "Transmission" and "Transmission2" in the yahoo group there you'll find some more explanation. But you have to click on the notes icon on the pics to be able to read the text.

101scout@yahoogroups.com