Author Topic: Stelvio 1200 - broken gearbox output shaft  (Read 400 times)

Offline guzzdi

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Stelvio 1200 - broken gearbox output shaft
« on: September 22, 2022, 04:33:55 PM »
When I was riding steep uphill on forest road, my bike suddenly lost traction. The engine worked fine, but no power goes to rear wheel on any of gears. Clearly major failure in a middle of nowhere :)
I called friends with off road trailer and we succeed to evacuate the bike.
At home we started to diagnose and first thought about failed clutch or final drive. We took out final drive (just as it’s easier) and realized that cardan shaft is not spinning (with engine running in a gear). We took out cardan and to the biggest surprise found the problem - the very end of gearbox output shaft broke from the gear shaft. Like somebody cut it wit a laser!!
I never experienced or saw something like that on any motorcycle in my life (I owned 6-7 during many years).
Did anybody hear or read about such failures and any reason (besides manufacturing defect) it may happen?
I’m thinking that replacing whole gearbox (but used on eBay?) is the best possible option. The alternative is to search for output shaft only and take apart gear box which sounds scary to the degree and probably not much cheaper at the end.
Any collective thoughts?
And the question - are gearboxes all same/identical for different years Stelvio 1200 4V? What about identicality between 4V 8V NTX etc? Just want to be sure which one to look on eBay.
Thx
Attached pictures of the broken part





« Last Edit: September 22, 2022, 04:42:51 PM by guzzdi »

Offline lucian

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #1 on: September 22, 2022, 05:16:22 PM »
Damn . I would say Moto Guzzi owes you a new shaft. I would contact them . It must be a manufacturing defect.

Offline Muzz

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #2 on: September 22, 2022, 06:19:56 PM »
See p.m.
Muzz. Cristchurch, New Zealand
03 Breva

Life is just a bowl of Allbran
Ya wake up in the morning and it's there

Offline guzzdi

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #3 on: September 23, 2022, 01:33:39 AM »

Wildgoose Chase Moto Guzzi

Re: Stelvio 1200 - broken gearbox output shaft
« Reply #3 on: September 23, 2022, 01:33:39 AM »

Offline guzzdi

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #4 on: September 23, 2022, 02:01:29 AM »
Damn . I would say Moto Guzzi owes you a new shaft. I would contact them . It must be a manufacturing defect.
The bike is Stelvio 1200 4V 2008.
I really doubt they will treat as "manufacturing defect" (though it really is)
Unless there is a good contact somewhere in corporate who can provide an exception authorization for parts and work to the local dealer/service center to fix it :)

Offline tris

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #5 on: September 23, 2022, 01:31:21 PM »
I'd  love to put that in the hands of one of our metallurgists and see if they could identify the failure mode.

If a lab inspection is a possibility, don't  touch the fracture surface and don't put it back on the remains of the shaft. They can tell loads by just looking under a microscope

It could be a manufacturing defect,  but might be something else entirely.
2017 V9 Roamer
2005 Breva 1100 (non ABS) "Bruno" - now sold
1995 Cali 1100 - carby   "Dino" -now SOLD
1993 TW125 "POS" - Resting

Offline guzzdi

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #6 on: September 23, 2022, 03:46:29 PM »
Tris,

I don’t have here in Seattle access to such level metallurgists :)
Besides that, I cannot even imagine what are possible any other reasons except manufacturing defect? I was single on a bike, going uphill gravel road, no luggage, on a second gear about 20 km/h.
Uphill steep, but I wouldn’t think of it as something extraordinary from a bike load perspective.
And what is a point to “prove” manufacturing defect? The bike is out of warranty anyhow…

Cheers

Offline tris

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Re: Stelvio 1200 - broken gearbox output shaft
« Reply #7 on: September 23, 2022, 03:59:11 PM »
Just idle curiosity,  as its an unexpected failure, and  us Mech Es are curious about such things

But, I agree, wouldn't change anything.



2017 V9 Roamer
2005 Breva 1100 (non ABS) "Bruno" - now sold
1995 Cali 1100 - carby   "Dino" -now SOLD
1993 TW125 "POS" - Resting

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