Shimming Supplement by lc
I've posted parts of the below recently elsewhere. A good compilation of most of the info needed in one spot:
I shimmed a transmission last summer and spent 2 1/2 days doing it (although there was a custom installation incorporated for 2nd) . For initial setup (before measurements were taken) I installed the shims according to this:
The first thing I noticed is I had to move the complete input shaft over by .5mm to get even dog engagement on both 4th and 5th gears...
If you need to get more or less clearance for the end needle bearing side clearance try reversing the 1/2 circlip that locates the shaft's ball bearing in the case (odd, but this will shift the complete shaft over a few thou).
Be sure to use the upgraded 2/3 shifter fork, which has a wider base. Also be sure to press the needle bearing races hard into their saddles when checking clearances.
Essentially you want mating dogs to bottom when engaged, if squeezed hard, but these same dogs not to touch when not engaged, if squeezed hard.
In my complete trans setup I could only use a toothed washer behind 3rd gear as I wanted max engagement of the dogs. (The toothed washers are only available in the thicker 1mm size). I am totally comfortable with this, as it is only this 3rd gear position that a circlip may get a direct thrust load when a gear's dogs are engaged..
Use an extra pair of pliers on the backside of the circlip to keep it from twisting during re and re. Finish up with new circlips and re-check clearances. Place the opening of the circlip so both circlip ends fall on a spline..
And more: The improved shifter fork and a ton of info (including shim part numbers) here:
I suggest you shim your trans like this^^^^ for the initial setup. Then install it into the case and adjust accordingly for deepest dog engagement (dogs engaged) but without clash (dogs disengaged). Apply a tight squeeze with fingers to gears being adjusted to check both situes...
Don't forget to push down on the needle bearing race (at ends of the shafts) to seat it in the case when doing any clearance checks....
Here's some more stuff for you:
Use good used circlips for setup, replace with new for final and re-check. (consider an "in service" circlip to have a one time installation life)
Kaw only makes .5 and 1mm shims. .25mm shims are available at Yamaha (fit the RD400). The pn is: 168-17428-01-03 www.partzilla.com/parts/search/Ya....SION/parts.html