XS650: Clutch Assembly

The bean counter was here. How do I know. In their wisdom, Yamaha left a Thrust Washer off the diagrams. It was there in their original manual. Then it disappeared. Between hub and boss they show a washer (25-50-2) and a thrust bearing – missing the washer (31-51-0.5) between needle bearing and hub..(e)..

correct diagram…shows the missing washer between basket and hub

 

section view

 

the raw product

 

Don’t forget the primary springs. Bits in the sump and filter. Clutch complaining. Broken springs. Can be replaced. I called Terry and ordered his vescanite blocks. I have no complaints.

the springs in the primary commonly break…a must do

 

While you’ve gone this far check the shift shaft and selector springs. They weaken and affect your gear changing. To fix you have to strip it all down anyway. I keep a bag of springs and simply replace them when I’m there.

the springs..selector above..shift shaft just poking its nose out from behing the clutch

 

make sure the adjustment is right

 

so

 

ready for first washers…25.2 x 36 x 1.0 : 25 x 50 x 2.0 then the bush

 

in that order…the smaller first, sits on the bearing outer

 

Look for wear on the edges of the basket and boss…can lightly file smooth…remember though, the more you take off the more play the clutch plates will have.

thrust bearing and its’ attendant washers…35 x 51 x 0.5 : thrust washer : 25 x 50 x 2.0

 

if you have it use the new thrust washer with more needles…the washer is the missing thin washer…comes as a set

 

so

 

then the boss…18mm…55-59 ft/lb…80 N.m…8.1 kg/m

 

there are 2 usual ways to secure the boss..2 washers and a nut…or lock tab and larger nut…where is the ball?

 

Load up the plates. First a friction then a pressure.

Then the pin that pushes the pressure plate. Don’t forget the ball like I have here.

Then fit the pressure plate. If the boss has a mark on it, it must line up with the hole in the pressure plate. If there is no mark, look at the pressure plate screw receivers in the boss. There is only 1 that lines up exactly with the centre of a tooth. It is important to mark this and line this up with the hole in the pressure plate.

these marks or points MUST line up

 

so

 

early p.p have no teeth…the teeth must locate at all times in the boss

 

i like to use these…allen head screws…dont strip the head and get a better feel

 

and looks like this…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 if using the originals

 

dont forget to check your clearances

 

push rod seal commonly leaks

 

check the push rod seal… lhs…here is a kit that replaces the original seal with a generic

 

This one from Twins Inn.

the push rods…dont forget the balls .. 5 16ths .. or replace the 2 smaller rods and a ball with a longer one

 

check the worm gear for function…the female part breaks-hard to see in all the crap-so clean it and lubricate…dont lose the bearing from within the male

 

look at your cables…clean and lubricate…this motion pro one is heavier, stronger and doesnt have so mush rubbing in the bend

 

CLUTCH PACKS

There are 3 variations. Pre 73, 6 plate pack : 73-78, 7 plate pack : post 78, spring loaded 6 plate pack.

The different packs, 6-7-6 plates, are interchangeable as a unit. The early, thicker plates (3.5mm) are not available anymore. If it hasn’t already long been done the rubber rings are removed and extra steel and friction plates are installed.

The 7 plate pack is known to increase risk of primary gear dampening spring failure.

	Steel Pressure	Friction
Pre Aug 73	1.6mm	6 @ 3.5 mm
Aug 73 – Aug 78	1.4 mm	7 @ 3.0 mm
Post Aug 78	1.4 mm	6 @ 3.0 mm

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