2. Assembly
First thing to remember here is that, in their wisdom, Yamaha left a Thrust Washer off the diagrams. Between hub and boss they show a washer (25-50-2) and a thrust bearing – missing is the washer (31-51-0.5) between needle bearing and hub..(e)..
Next point to remember is 2-2-2...each step requires 2 washers..see above diagram
Install:
2 washers/shaft-to-hub-bush (hub) thrust bearing/2 washers (boss) 2 washers/nut
*Crankcase
*Bush
*Washer..25.2-36-1.0
*Washer...25-50-2
*Hub
*Washer...35-51-0.5 **this is usually missing from diagrams, therefore gets left out**
*Thrust Bearing
*Washer...25-50-2
*Boss
*Washer...plain
*Washer...Spring Bellville/lock washer
*Nut
*Push Rod End
This sequence ignores plate packing and Mikesxs recommendation that you pack thrust bearing direct against hub, then covered by the 2 washers.
Also be aware that when the internal 2 piece push rod was introduced many parts books and manuals showed, in pictures, installation with the turned down end pointed towards the clutch hub, instead, this reduced end locates into the worm gear pushing against the ball bearing crimped into it...you will know its installed wrong when you either cant close the case or have no pressure at the clutch handle
So, before starting check the 2 shift mechanism springs
Ensure:
-the spacer is ok
-you have the 2 washers
-there are no rubbing marks
-the primary drive dampening springs are intact
-the hub basket dogs are not worn, cracked, bent, broken..bent/broken, replace-rilled, if not too bad lightly file-reduces friction plate catching, if bad, replace
...install...
-thin washer
-bearing...mikesxs has a good replacement
-thick washer
-boss, check that splines are not worn
-washer
-spring/lock washer
-nut...18mm...55-59 ft/lb...80 N.m...8.1 kg/m
...install...
-make sure the ball bearing is in the shaft...oil
-push rod(s - bearing)
...install clutch pack...
-pressure plate...if yours has splines make sure they register
-springs...all same size and within specs
-screws...tighten with impact driver - 5-7 ft/lb...9.0-9.5 N.m...0.8-1.0 kg/m...use #3 bit so you dont damage the phillips head
CLUTCH PACKS
The different packs, 6-7-6 plates, are interchangeable as a unit. As the early, thicker plates (3.5mm) are not available anymore, Mikesxs suggest removing the rubber rings and installing an extra steel and friction plate pair in the early clutch packs.
The 7 plate pack is known to increase risk of primary gear dampening spring failure.
My personal suggestion is to change in a later model 6 plate pack - straight swap.
When installing
- soak new friction plates in oil-overnight if possible...Note that your bike needs 20W-40, which is available at truck stops and auto stores...eg Shell Rotella, Pennzoil without the additives found in modern automobile motor oils. Wrong oil = clutch problems...big time!!!
- check steel plates for warping-lay on plate glass, if you can rock it or slide a 0.008"(0.2mm) feeler guage under, replace
- buff the sharp edges smooth...as these are stamped-out, the top edges are rounded by the die, the bottom edges are left sharp...buff these smooth with a wire wheel
- scuff the surfaces lightly with emery paper to remove glazing - wash
- check friction plates for wear...new-3.0mm...min-2.7mmm (earlier, 3.5mm new/3.1mm min)
- lightly bevel the edges of the friction plate tabs with a file...this helps prevent them catching on the basket fingers
NOTE...when installing the later sprung 6 plate pack, be aware that there are 2 different steel plates...the plate that belongs to the anti loading pack that goes into the boss first is thicker than the others, 1.6mm as opposed to 1.4mm - dont mix them up
Alignment
- if not aligned properly the cluth will be noisy and not work properly
...this hole must align with the mark on the boss
...like this
...when there is no mark or hole then align as below...only 1 screw boss lines up with a tooth centre-this is where the pressure plate must align...mark the tooth