Clutch cover difference 72-81

[garyr]

Does anyone know if an earlier model 72 clutch side cover will fit a 81. The problem I'm having is I've done just that and I get a leak by the kick starter. I throughout the old cover so I can't check but I'm thinking the bushing lip for the kick starter is thicker on the older models not allowing it to seal 100%

I realize not many my have ever heard about his problem but it worth asking.

 

[HooliganCycles]

I would just get on yamahas web site and see if the part numbers are the same

 

[jamesgs4]

IIRC, they are slightly different, due to the change from 5 to 6 clutch discs. I read somewhere that the newer one will fit fine on the older cases, but the older one will not match up as well to the newer cases.

 

[garyr]

I had thought the kick starter shaft and the older case may have had a larger boss/bushing not making it seal correctly. That isn't the problem, I just checked again and the kick stater still has play in and out with the case on.

Originally I did not have the dowels on either side of the case ..I threw them out with the old broken case my mistake. I got some NOS dowels and just put the case back together. I used 2 gaskets this time and set to the case bolts to the right torque...we will see.

The old gasket did not leak until I started the bike..funny. Than it leaked like a sieve. I'm about 4 days away from starting the bike..will check it then.

Thanks for all the help.

 

[blackbetty]

IIRC, they are slightly different, due to the change from 5 to 6 clutch discs. I read somewhere that the newer one will fit fine on the older cases, but the older one will not match up as well to the newer cases.

I use a 1981 6 pack clutch on my 75; replaced the original 7 pack with the late model spring loaded unit, so we know that covers from 73-81 should work.

Here's a note on clutch packs pulled from here:

http://thexscafedotcom.wordpress.com/2011/01/19/xs650-clutch-assembly/

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

 

[garyr]

Here's some additional information about clutch parts. Mikes clutch bolts are to long and they will damage the clutch basket. The problem is you will never know other than seeing metal flakes in your oil. I had to take mine apart again after this oil leak and found lots of metal in the oil so I took the clutch part to find the bolts gouged into the basket.

Also I found the Mike's replacementet springs are way to hard...my clutch was like I had to pull in 20 pounds of pressure. I ordered NOS springs and bolts....clutch is perfect now.

you can see the bolt on the right is Mikes and is to long.

Damaged basket. Grove around center bearing.

Stock bolt is on the right.

 

[grepper]

I do believe they are all interchangeable. I have a 79 cover on a 72 motor (my red bobber). The 80 xs650 I sold last summer had a 77 motor with the 80 cover. Now I'm rebuilding an 80 motor and have a 72 cover for it. It fits fine, but I haven't run the engine yet.