Very rarely do any of the shafts have more than one .004" or .008" shim on one end. The location of these shims is relatively simple because every shimmable shaft in the gearbox has a different diameter.

The shift drum end has a 12 mm diameter. The left end of the layshaft is 14 mm. The right end of the layshaft is 16 mm. The left end of the mainshaft is 17 mm. The right end of the mainshaft is not shimmed. The right end of the kickstarter shaft is 15 mm and the left end is 20 mm. The selector shaft is normally not shimmed. Because of this, it is very easy to determine on which shaft the shims belong. Fig. 52A gives the part numbers and sizes of all the transmission shims.

Transmission Shim Chart

033-176-I (.002" thick)
Left end of Layshaft 
033-176-II (.004" thick)
033-176-IV (.008" thick)
Right end of layshaft 
033-292-I (.002" thick)
033-292-II (.004" thick)
Right end of kickstart 
033-292-IV(.008" thick)
033-292-X (.020" thick)
921-111 (.002" thick)
Left end of mainshaft 
921-112 (.004" thick)
921-113 (.008" thick)
050-404-I (.002" thick)
Shift drum 
050-404-II (.004" thick)
050-404-IV(.008" thick)
050-404-X (.020" thick)
Left end of kickstart 
 911-139-II (.004" thick)
911-139-IV (.008" thick)
911-139-X (.020" thick)
991-139-II (.004" thick)
Crankshaft shims 
991-139-IV (.008" thick)
991-139-X (.020" thick)

FIG. 52A

5. The next step is to find out how many shims belong on each shaft. Start by putting all the shims back on all the shafts. Then, install the layshaft with all of its shims and gears in the right engine case. Install the three crankcase guide pins in their respective holes and lay a new center gasket on the righthand case surface. Install the left crankcase and insert and tighten at least five of the engine case screws. The left end of the layshaft will be exposed through the bushing in the left engine case. The end play of the layshaft can be measured from that point.

6. There are several ways to take this measurement. A dial gauge is the most accurate, but a vernier caliper will suffice if a dial gauge is not available. The layshaft can be moved back and forth by reaching in through the center of the mainshaft bearing with a hooked tool similar to a pry bar, and catching hold of the shaft. Pull the shaft towards you by hooking the tool behind the 4th gear on the layshaft. Push it away from you by pushing on the far righthand gear. These two gears are made right onto the shaft and will not allow you to take a false reading.

7. If a dial indicator is used, it must be attached firmly to the left engine case, with the plunger of the gauge touching the left end of the layshaft and parallel to it. Move the shaft back and forth. The end play should be .010" to .015".

8. If a vernier caliper is used, locate a fairly strong, straight-edged piece of strap metal that is longer than the engine case is high. This will be used as a reference point for the caliper. Put the strap across the cases and hold the

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