V100 with Broken Kayaba Shock

[janguzzi]

Found this on Facebook. Shock not mounted correctly but is this really the reason?

Broken Kayaba shock:
https://www.facebook.com/photo?fbid=10232710922020458&set=pcb.826598325713275





https://www.facebook.com/groups/387840452922400/ (translated with deepl.com):

I hope the translation will allow you to understand! Good morning to all V100 Mandello base and V100 Mandello Navy owners. Some of you may know about the catastrophic failure of the Kayaba shock absorber fitted as standard on these models, a failure caused (it seems) by the lack of a spacer, number 8 inside the exploded view. It has now been a month and my bike is repaired, but I am not picking it up because I no longer want to ride it with that shock absorber and am waiting for an aftermarket one that I will mount AT MY EXPENSE! Last night I learned that a second Mandello V100 bike had the same failure (photo in first comment)...one should not have happened, two is unacceptable! UNACCEPTABLE, too, is the fact that Piaggio a good month after the first incident, has not undertaken any urgent campaign to make sure its customers/users are safe! At this point, within my means, I will do so by informing as many people as I can reach of the potential risk of riding a basic V100, or a Navy. Have your bike inspected immediately, especially check that the two spacers #8 on the exploded view are present and mounted correctly! Regards to all!

[Frenchfrog]

Seen photos of several of these breakages. Looks like a recall should be about to happen....

[blu guzz]

I had that happen once on a BMW while on a trip.  I had to ride it 350 miles that way.  Much slower but worked.

[lazlokovacs]

oh my

cheap components?

[sdcr]

I’m not extremely surprised, as first, and sometimes second year models, exhibit “teething” issues.
Not fun, but if Piaggio steps up, should be ok.

[Bisbee]

My 2021 850 Special leaked oil from the left rear KYB shock at 700 miles. The dealer sent Piagio some photos and it was replaced with no problems. Unfortunately, there seem to be some quality issues with KYB. For a shock mount to break and the potential loss of control certainly points to a recall. Who knows what country/factory they are made?

[Antietam Classic Cycle]

Sounds to me like the bottom eye of the shock was locked into place vs. being able to rotate like it should.

"Have your bike inspected immediately, especially check that the two spacers #8 on the exploded view are present and mounted correctly!"

That would point to incorrect assembly, not a problem with the shock itself. 

[bad Chad]

oh my

cheap components?

Maybe the ones that have failed are being ridden by very fat guys?   I know I've broken a few camp chairs in my days.

[Dave Swanson]

Sounds to me like the bottom eye of the shock was locked into place vs. being able to rotate like it should.

"Have your bike inspected immediately, especially check that the two spacers #8 on the exploded view are present and mounted correctly!"

That would point to incorrect assembly, not a problem with the shock itself.

As per usual you can always get the real story from Charlie.   

[Antietam Classic Cycle]

As per usual you can always get the real story from Charlie.   

Just a guess on my part - I haven't even seen a V100 in real life yet.

[lazlokovacs]

While I have maximum respect for Mr Mullendore... yeah, like he said, jury's still out on this one...

Will be interesting to see if guzzi do the right thing

Sorry, have to run I just saw a bunch of pigs flying past my window

[Huzo]

While I have maximum respect for Mr Mullendore... yeah, like he said, jury's still out on this one...

Will be interesting to see if guzzi do the right thing

Sorry, have to run I just saw a bunch of pigs flying past my window

Three different ones…?

[lucian]

I have only found reports of this one failure and to my eyes the photo depicts a cold weld.   

[Huzo]

I reckon the eye of the shock has not been pivoting in normal use.
If it was, there  would only be compression and tension forces. If it was not able to rotate on the pivot bolt, then there would be a “tearing” force at play.

[Tusayan]

I reckon the eye of the shock has not been pivoting in normal use. If it was, there  would only be compression and tension forces. If it was not able to rotate on the pivot bolt, then there would be a “tearing” force at play.

You could right about that - it’s the first possibility that comes to mind.  If the shock has these it should be swiveling between the eye and the shock body, and the bolt should clamp the eye immobile.

On my V85TT (and others) the Kayaba rear shock eyes were not greased adequately at the factory and both ends of mine were almost seized when checked after 6000 dry miles.  If they seized completely it would put an unintended bending load on the shock body.

[Frenchfrog]

That seems to be consensus here in France too as the bushes on at least one of the bikes don't appear to be positioned correctly.For a long while now the factory at  Mandello appears to have quite a lot of temporary staff on the assembly lines and that could be a partial cause for this ..easy enough to check if you know what to look out for.

[Huzo]

So when the shock fails in this way, how far does the swingarm deflect ?
One would think that it collapses far enough for the wheel to jam under the rear subframe ? If that were true, not the nicest thing in the world for the universal joint..(or the rider).

[Huzo]

You could right about that - it’s the first possibility that comes to mind.  If the shock has these it should be swiveling between the eye and the shock body, and the bolt should clamp the eye immobile.

On my V85TT (and others) the Kayaba rear shock eyes were not greased adequately at the factory and both ends of mine were almost seized when checked after 6000 dry miles.  If they seized completely it would put an unintended bending load on the shock body.

Only if the eye spacer was intended to rotate on the bolt, one would think that the rubber between the spacer and the bolt is where the intended motion takes place.
I think the eye may have become clamped during tensioning of the bolt, due to inadequate length of the spacer.
This would result in a “peeling” motion contributing to what we see here.
Imagine you had the shock upright in a vice clamped tightly at the bottom eye.
If you wanted to tear the body loose from the eye (although brutal), that’d be how you’d achieve it.

[Huzo]

the bolt should clamp the eye immobile.

Did you mean “clamp the SPACER” immobile…?

[Frenchfrog]

I've always understood that the shock would rotate on the spacer rather than on the rubber Huzo.One theory as to the shock breaking was because the spacers were incorrectly positioned and clamped the shock lower tight  which makes sense to me at least.
After something like that happening it would take quite a lot of resolve and re assurance for the owner to get back on I guess.

[Huzo]

I've always understood that the shock would rotate on the spacer rather than on the rubber Huzo.One theory as to the shock breaking was because the spacers were incorrectly positioned and clamped the shock lower tight  which makes sense to me at least.

Yes FF, the shock OUTER will rotate on the spacer via the rubber, but the spacer must not /does not rotate on the bolt.
The rubber twists to allow for the motion.

[Tusayan]

If the V100 Kayaba shock design is like that on the V85TT, and if my memory is correct about that design, I don’t believe there is a rubber/metal bushing.  There is instead a fitting similar to a rod end (Heim joint) fitting.  If the eye is intentionally clamped by the mounting bolt then the shock body rotates around the ball, greased and with rubber seals to prevent egress of the grease. If the ball/eye fitting isn’t greased and galls or rusts it could develop very high friction, putting bending loads on the shock as the rear suspension moves through its range of motion. The V100 shock appears weak in its ability to take an unintentional bending load like that.

This is a V85TT Kayaba shock.  It’s not 100% clear to me that the V100 shock has the same design end fitting, and this failure mode would require that to be so, and also that the shock be unable to rotate on the bolt if the ball seizes.





Also worth noting that on the V85TT these squeak a lot before they seize.

[Huzo]

Fair enough Tus…
Time will tell.

[SIR REAL ED]

I have only found reports of this one failure and to my eyes the photo depicts a cold weld.   

Excellent speculation on the part of all participants.  It would be great if any V100 owners would post pictures.

I think Lucian may have nailed it.  That picture does look suspiciously like only one drop of Super Glue was applied rather than the factory recommended spec of 5 drops.

The reply of Guzzi/Piaggio etc. will be most revealing.  KTM would be very secretive.  Especially with the owners and even with the dealers.

[Tusayan]

Re the missing spacer theory - it would have to be a spacer on the inside of the lower shock mount, when missing allowing the mounting bolt to clamp the ring/washer at the bottom of the shock body against the aluminum shock mount.  This would have the same effect (bending on the shock body) as a ungreased/seized lower eye fitting.   However I think the hard contact would make a very noticeable sound as the suspension moves, but perhaps not.

The cold weld idea does not immediately seem right to me, as there appears to be a portion of the shock body still attached to the ring.  It looks like it failed above the weld, but it’s hard to to tell exactly from a photo.  Photos sometimes lie and it’s otherwise a pretty good possibility.

[jacksonracingcomau]

Sounds to me like the bottom eye of the shock was locked into place vs. being able to rotate like it should.

"Have your bike inspected immediately, especially check that the two spacers #8 on the exploded view are present and mounted correctly!"

That would point to incorrect assembly, not a problem with the shock itself.

That’s the way I read it too, perhaps someone will post the relevant page showing spacers #8

Yes FF, the shock OUTER will rotate on the spacer via the rubber, but the spacer must not /does not rotate on the bolt.
The rubber twists to allow for the motion.

No matter how many times I read that, I can’t get where the rubber that “twists” is, no rubber in a modern monoshock eye afaik , check your V85 to see how they work

Someone post a pic of v100 parts book for the sake of clarity

[PeteS]

Big part of the problem is the V100 shock has no gusset like the V85 shock has.

V85



delete duplicate keywords


V100







Pete

[Huzo]

That’s the way I read it too, perhaps someone will post the relevant page showing spacers #8

No matter how many times I read that, I can’t get where the rubber that “twists” is, no rubber in a modern monoshock eye afaik , check your V85 to see how they work

Someone post a pic of v100 parts book for the sake of clarity

If the shock has a ball end, then the rotation is achieved there. I’m trying to remember if my replacement shock on the V85 is the same.
Don’t remember.
I think the Ohlins has a sleeve with rubber, maybe not.

[jacksonracingcomau]

If the shock has a ball end, then the rotation is achieved there. I’m trying to remember if my replacement shock on the V85 is the same.
Don’t remember.
I think the Ohlins has a sleeve with rubber, maybe not.

It would have to be a “poverty pack “ ohlins or cheap copy if it did, even twin shock ohlins had helm joints 45 years ago (i still have them)

[SIR REAL ED]

Big part of the problem is the V100 shock has no gusset like the V85 shock has.

V85



delete duplicate keywords


V100







Pete

Hard to tell from the angle of the photos, but to my eye that looks like no weld is there at all. 

As if the lower shock "eye" mount and the shock body are both a single cast component.

Shirley, if they were welded, more weld that that would have been applied.

Maybe someone at the factory confused the paint thickness gauge with the weld thickness gauge?