Swing Arm thrust washer Breva 750

[hzbloke]

I took the swing arm off to grease the splines and found that the thrust washer on the right hand pivot pin was not there (#13 on the diagram). I doubt very much that it was ever there. I've done 60,000km on the bike and never noticed any odd handling. I feel a little bad about having done 60,000km without checking the splines but they had been greased, probably in the factory, and are in excellent condition. Indeed everything on the swing arm (bearings, pivot pins, rubber boot) is in very good condition.

For now I've put it back together without the washer. I know it locates the swing arm but clearly it is not essential to the well-being of the bike. Is it in anyway special or would any washer of the same dimensions do the job?  And does anyone have those dimensions?

[guzzisteve]

Now, this intrigued me. Did some research. Bingo------- same washer used in all smallblocks all the way back to 1977. Even the 6 speed uses it. Didn't look at V9

SO, WHO HAS ONE OFF. I i remember correctly(iffy) it's bout 1/8"
It will do nothing but move wheel over 1/8", ujoint has no carrier bearing. It may be closer to the swingarm encloser.
Well, that's at least an answer.

[SmithSwede]

Are you absolutely certain the washer isn’t there?  I’ve found mine “glued” to the bearing a few times with dried crusty grease.

[hzbloke]

Are you absolutely certain the washer isn’t there?  I’ve found mine “glued” to the bearing a few times with dried crusty grease.

A good suggestion but I'm sure it's not stuck there. I cleaned everything up pretty good. There's the chance that it fell off but I'm blessed with a fairly large, clear concrete floor in my shed and, so far, there's no sign of it.

I did find the dimensions though. It is 15mm ID x 23mm OD x 2mm

[Bob Wegman]

I just had the swing arm off on my V7C. In addition to locating the swing arm I think it provides some clearance for some wiring that is located between the frame and swing arm.

[Muzz]

Chuck has detailed the setup.  It is mainly used to centralise the UJ in the swingarm as I understand it.

Insert swingarm.
Do up LH bolt until all sidways movement is gone with wave washer compressed, and do up lock nut.
Do up RH bolt until firm, make sure the movement of the arm is ok, and do up lock nut.

Something like that anyway.

While the arm is off I check to make sure the swingarm bearings are free.  If not, I flick the seal and repack with grease and give them a spin.  My bearing man reckons that the bearing used is really not the best for that application.  Because the movement is very limited the balls do not get to spin so just wiggle in the same location and do not allow any grease to be spread around inside.

[Huzo]

A good suggestion but I'm sure it's not stuck there. I cleaned everything up pretty good. There's the chance that it fell off but I'm blessed with a fairly large, clear concrete floor in my shed and, so far, there's no sign of it.

I did find the dimensions though. It is 15mm ID x 23mm OD x 2mm

Bottom right corner..
Orbost..?

[hzbloke]

Bottom right corner..
Orbost..?

Geographically you are correct but I'm really a bit less bottom and a bit less right - Beechworth. But on a map of the world I reckon my description is good enough.

[Muzz]

Must say that it is not a normal washer, it is wave washer.

The washer itself is quite thin but with the wave I am guessing it would come to about 3mm.

[hzbloke]

Must say that it is not a normal washer, it is wave washer.

The washer itself is quite thin but with the wave I am guessing it would come to about 3mm.

Are you sure about that Muzz? It would sorta make sense but the photos I have found show it to be just a plain flat washer. Here's one from Gutsibits UK:
                                               

[SmithSwede]

Mine is flat.  No wave

[Pizza Guzzi]

Same here, flat washer.

Glenn

[Muzz]

Are you sure about that Muzz? It would sorta make sense but the photos I have found show it to be just a plain flat washer. Here's one from Gutsibits UK:
                                               

100%.  At least, that is what was fitted in the Breva. Definitely a wave washer, not flat.

[SmithSwede]

I’m pretty sure the V7 was fitted with a flat washer in the Northern (normal) hemisphere. 

South of the equator, due to the Coriolis force and cane toad venom, a wave washer is required. 

[malik]

Just checked - the '10 V7C, the '14 V7S & the Breva all have the flat washers. Didn't look for the old Nevada one. And we are all south of the equator, at least we were the last time I checked. That wave washer isn't the source of your gearbox shenanigans, is it, Muzz? It's nearby. Could be contagious.

(Aparently it doesn't seem to matter which you have, whatever works).

[Muzz]

That wave washer isn't the source of your gearbox shenanigans, is it, Muzz? It's nearby. Could be contagious.

No, in my case the gizmo had come loose from the whozzix.

[malik]

And now in the same vein - I haven't even started to put the bike back together, and I've got a spare washer! Wheeled the frame off the motor this morning, separated the lower frame rail/centrestand from the motor, and Lo & behold, on the RHS, a washer - a flat one, 18x10x2, dirty along the edge, but no rust on either face. None yet found on the LHS. ?? From somewhere on the bike? Or just kicking around the workshop? Set up the motor on the lift near the door ready for a scrub & clean tomorrow & went home. A tipple before tea will solve the problem, I'm sure.

[Muzz]

Not from the spreader bar underneath the frame?

[steamdriven NZ]

Chuck has detailed the setup.  It is mainly used to centralise the UJ in the swingarm as I understand it.

Insert swingarm.
Do up LH bolt until all sidways movement is gone with wave washer compressed, and do up lock nut.
Do up RH bolt until firm, make sure the movement of the arm is ok, and do up lock nut.

Something like that anyway.

Mine has always had the flat washer. Muzz, the two pins are wound in with the washer fitted to the RH pin. You wind them in until firm by hand then measure the extension of the outer thread showing. Wind the shorter one out and chase it up with the other side going in until the two dimensions are equal. Fit big chrome lock nuts.
If you don't have a washer you can adjust the pin protrusion to compensate and achieve the same thing. 

[Muzz]

Don't know why mine had the wave Kev,   perhaps Luigi decided he would just throw (another) spaniard in the works. <shrug>

Most people seem to be saying that their ones are flat.

[Chuck in Indiana]

Don't know why mine had the wave Kev,   perhaps Luigi decided he would just throw (another) spaniard in the works. <shrug>

Most people seem to be saying that their ones are flat.

They've been flat since the Pleistocene.. 2mm from memory. It makes centering up the swing arm a no brainer. Just put it on the right pin, engage both pins in the bearings, run the left in until the washer touches, run the right one in for "feel" and lock the pins with the big jam nuts. No thinking. No measuring. My kind of job..

[sign216]

A good suggestion but I'm sure it's not stuck there. I cleaned everything up pretty good. There's the chance that it fell off but I'm blessed with a fairly large, clear concrete floor in my shed and, so far, there's no sign of it.

I did find the dimensions though. It is 15mm ID x 23mm OD x 2mm

As for me, there must be gremlins that snatch stuff up during disassembly.  Things just disappear....

[Muzz]

They've been flat since the Pleistocene.. 2mm from memory. It makes centering up the swing arm a no brainer. Just put it on the right pin, engage both pins in the bearings, run the left in until the washer touches, run the right one in for "feel" and lock the pins with the big jam nuts. No thinking. No measuring. My kind of job..

That's the way I did it Chuck, just with the wave washer that came out of it.

I guess that next time I do the splines I could look for a flat washer to replace it with.  2mm you say?

Having thought about it, any disadvantages with just leaving it the way it is?

[Pizza Guzzi]

I did mine exactly as Chuck described and all is well. If it was me I would change the wave washer for a flat washer because ( a) its an easy peasy job to do and ( b) it's one less thing to worry about.
In reality it would probably be ok to leave the wave washer in there but it's really not an application for a wave washer. The flat washer is more of a spacer than anything, there is very little axial loading on the pins / bearings at the swing arm mount according to my hazy memory from engineering classes from 45 years ago 😄

Glenn

[Chuck in Indiana]

It's just a spacer to center up the swing arm as far as I know.

[Muzz]

Next tire change and spline grease I will change it out.

Weird.

[malik]

Not from the spreader bar underneath the frame?

Found another washer matching other one the other day - ? fallen from the engine block on the other side - looks as if that's the culprit - seem to belong to the centre pin that goes through the engine.  I guess that's the spreader bar you indicated. The saga continues.

[hzbloke]

Thanks to Steve at Guzzi Spares in Victoria I have the missing washer and I have fitted it. I'm happy that the bike is now as per spec but I've gotta say that it's made no discernible difference.

It turns out that is is possible to fit the washer without removing the wheel or the swingarm. With the bike on the centre stand and the swingarm supported at the front on a bottle jack and a piece of wood there is just enough room to wind the right pin out and slip the washer between the swingarm and the gearbox. It's fiddly but not hard.

[Pizza Guzzi]

Good work.  It certainly won't do any harm having the correct washer fitted 

Glenn

[hzbloke]

I take back everything that I ever said or thought about those diligent, professional, exacting (also no doubt handsome and virile) workers at the Moto Guzzi factory.

The 'missing' washer re-appeared this week lurking behind a box far, far away from the bike, on the floor of my shed. I seems to have broken a couple of laws of physics to get there, but there it was. My fading hearing clearly didn't pick up the ping (or whatever noise a thing makes as it violates the space-time continuum) as it hit the floor and my search perimeter was obviously too modest.

My apologies to those wonderful ragazzi.