2009 Stelvio. Cracked Fork/Axle Pinch Bolt Damage. Help Please.

[catneck]

I have had the bike 3 weeks.
10k on the clock.
P O noted new tires front & rear.
I quickly logged 1000 miles, as this bike works well for me.
No dealers within 300 miles.
On a work trip via car last week.
Stopped at Moto Guzzi dealer.
Tech had an NTX on the rack.
I asked him what to look for.
He pointed to the axle pinch bolt.
Said to inspect mine when I returned home.
I did.
Both cracked.
Bike immediately parked.
Called dealer.
Out of warranty.
MG will not cover.
I have learned that they are 1 year only forks.
And only available as a complete leg (includes fork tube and internals).
Any help available?
Frustrated, as I like the bike.
I believe this to be a safety issue.
MG must be aware, I have seen this referenced before.
And MG remedied before.
Any pointers?
Later model/cross model fitment?

[guzzisteve]

P O noted new tires front & rear.

Most likely time they got over tightened!

[catneck]

P O noted new tires front & rear.

Most likely time they got over tightened!

At an established shop no less. Which he cannot find a receipt for.
Looks like I am paying them a visit.
Arghh.

[Kiwi_Roy]

I'm sure a good welder can fix it for you, the pinch bolts shouldn't be super tight.

Can you post a picture

[normzone]

Yes. There you go. Emphasis on a GOOD welder.

I was panicking for you for a moment there, but [Kiwi_Roy] has it right. Unless it's some extremely strange alloy, it should be weldable by a welder who knows his stuff.

[catneck]

URL=http://s295.photobucket.com/user/cat_neck/media/Moto%20Guzzi%20Stelvio/20150830_183405_zps6vqdyvj5.jpg.html][/URL]

[Vasco DG]

The bottom of the leg is a casting and critical. I would strongly advise against welding.

The only reason the castings crack is because they get over tightened by a gorilla. This is the reason we have inch/pound torque wrenches. To help prevent it happening Guzzi recommended swapping from the hex head pinch bolts to Allen heads which are less likely to be over-torqued by 'Captain Simian' at yer average tyre shop.

Pete

[oldbike54]

The bottom of the leg is a casting and critical. I would strongly advise against welding.

The only reason the castings crack is because they get over tightened by a gorilla. This is the reason we have inch/pound torque wrenches. To help prevent it happening Guzzi recommended swapping from the hex head pinch bolts to Allen heads which are less likely to be over-torqued by 'Captain Simian' at yer average tyre shop.

Pete

 Gotta agree with Pete , this type of casting should not be welded . Maybe try to locate a used set .

  Dusty

[catneck]

I like the used parts idea.
New is $550 each leg.
I hate to invest and have this recur.
I know of the allen screw replacement, and will do that.
Is there a source for MG spares ala Beemer Bomeyard?

[beetle]

I never let anyone near my hubs/axle/wheel hardware. Maybe Roper.

As this is a critical component, I would not be welding. I would not expect anyone to own up to over-torquing them either.

The lower fork/hub is available as a separate part. AF1 have them listed at $454.58.

[oldbike54]

I never let anyone near my hubs/axle/wheel hardware. Maybe Roper.

As this is a critical component, I would not be welding. I would not expect anyone to own up to over-torquing them either.

The lower fork/hub is available as a separate part. AF1 have them listed at $454.58.

 Yeah , and maybe not even Pete after a night at the pub 

 

I like the used parts idea.
New is $550 each leg.
I hate to invest and have this recur.
I know of the allen screw replacement, and will do that.
Is there a source for MG spares ala Beemer Bomeyard?

  Maybe someone here will respond . Damn , MC spares are expensive . Good luck .


  Dusty

[Vasco DG]

How does the price of a set of the later 45mm forks compare?

[pauldaytona]

In the service training  docs from guzzi they tell it is not a safety problem. I know someone who has it on the road in Russia, and they put a bolt trough it and he rode home with that.

[Kiwi_Roy]

That design sucks, it should only take a pair of 6mm bolts to pinch that together

I agree now that I see it not the sort of thing you want to weld but at $1000 for the pair I would certainly be asking around.

Another option might be a good machinist who could machine up a pair of slip in ends from billet.

[leafman60]

Dang, catneck.  I know this causes you some bother.

Your choices are this:

1. Replace the broken castings with new or used parts.

New parts are going to be expensive. Used parts will be very difficult to find since these bikes are very rare in the the biking population. I checked Pinwall Cycles (purveyor of used Guzzi stuff) and they have an 09 tank but no fork parts. I see nothing on Ebay. You may should call Curtis Harper at Harper's Moto Guzzi.  They can often help with Guzzi needs. Same with Moto International in Seattle.

2. Make do with your damaged parts.

Yes, this looks serious and bad.  However, it may not be as critical as some speculate. The pinch clamp's main function is to allow alignment and smooth movement of the forks legs before tightening everything up. Of course, the pinch helps secure the axle in its bore but the likelihood of the axle falling out without a tighten pinch clamp seems remote if the axle nut is properly tightened.

Still, I can understand trepidation over the security of your front wheel.

By the way, I wouldn't downrate anyone for over tightening these pinch bolts. I can understand someone thinking they needed to torque them down good and the casting doesn't look vulnerable upon casual observation.  Of course, a dealer shop should have been knowledgeable of the peculiarities of these bikes but ... whatever.   Things happen.

As already suggested on here, if you wanna salvage the stock parts, consult a good welder. A practical and workable fix may be a welding job. Any resulting weld joint should not be subject to much subsequent stress caused by tightening the pinch clamp. The weld should be made with the pinch gap opened only enough to allow alignment of the fork and/or removal of the axle so, when tightened, the weld joint is subject to minimal flex. The weld joint should be as small as possible with not a lot of build-up around the joint that will make it most rigid.  The idea is to preserve some of the clamp flex in the material on either side of the weld. Being aluminum complicates this job.

I am not sure if this will work but talk to a good welder and be sure he realizes the function of the pinch clamp. You don't have much to lose by trying.

[Vasco DG]

Sorry David but this post gets you very close to 'Dangerous Idiot' territory. I know it's not your life you're playing with but if your understanding of the laws of physics is so poor please, just shut the f*** up.

Pete

[John A]

I'd take it as a sign from above that it's time to upgrade the complete front fork assembly, maybe those 45mm forks Pete mentioned.

[leafman60]

Sorry David but this post gets you very close to 'Dangerous Idiot' territory. I know it's not your life you're playing with but if your understanding of the laws of physics is so poor please, just shut the f$!k up.

Pete

Pete, you are always way beyond that point yet you never take you own advice to "just shut the f$!k up." lol

[rdbandkab]

This fork bottom looked close to having the same bracketry as the NTX fork.   Just a thought.  It's a Duc part, but more importantly, it's a Marzocchi part.  This might be another avenue for bottoms.  You would have to verify tube diameter and axle diameter of course.

http://www.ebay.com/itm/Ducati-Monster-1100-EVO-Marzocchi-Right-Side-Lower-Fork-Leg-Foot-Caliper-Mount-/271313974794?hash=item3f2b92b60a&vxp=mtr




Price:
US $168.74
Buy It Now

[mtiberio]

I had a 2002 Pegaso, and I did the same thing to the Marzocchi forks that came stock on that. Shortly after I discovered it, I had the good fortune of being left turned by some lady who's mother had just died. Insurance paid for a set of forks on that bike. Seems if you are used to clamping down on the old 35mm sliders of yore, the same torque applied to the dual pinch bolt "modern" forks can have deliterious effects.

[leafman60]

I had a 2002 Pegaso, and I did the same thing to the Marzocchi forks that came stock on that. Shortly after I dscovered it, I had the good fortune of being left turned by some lady who's mother had just died. Insurance paid for a set of forks on that bike. Seems if you are used to clamping down on the old 35mm sliders of yore, the same torque applied to the dual pinch bolt "modern" forks can have deliterious effects.

Lol, well,I guess that's one way to solve the problem. However, I hesitate to advise a staged wreck to have insurance pay the tab. lol

The Ducati parts will be expensive to buy and adapt too.

Again, either get new/used non-cracked parts or consult someone who knows more about welding aluminum than any of us and consider a repair.

Paul's previous post is also informative.

In the service training  docs from guzzi they tell it is not a safety problem. I know someone who has it on the road in Russia, and they put a bolt trough it and he rode home with that.

Another possibility from an adept machine shop is to fashion another clamp assembly, maybe from steel or stainless steel, around the broken clamp section to effect another clamp on top of the broken aluminum clamp section. This may be better than the stock design.

[luthier]

Disappointed Leafman. It's not an option to weld but you want to insult Mister Roper and continue the Dangerous Idiot theme.
It's this kind of attitude that drives good men mad and leaves internet boards being populated by fools, thus lowering the IQ to ground level.
Cease and desist from this annoyance. This board is better than what you seek to drag it down to.

[Lannis]

That design sucks, it should only take a pair of 6mm bolts to pinch that together

It does look like a bad design, but it's similar to ones that other makers have used before.

When this issue first came up, I sat down next to my Stelvio forks and considered them.

First of all, very little "clamping force" is needed to hold the axle.   Matter of fact, with both clamps broken, the front axle stays in place anyway.   It looks to me like the "clamps" are there to literally keep the axle from rotating and rattling around.

Second, the fact that TWO bolts side by side are clamping this thing down is problematic, even if you're using a torque wrench.   I took a 6" long box end wrench, choked up on it halfway so that I had only about a 3" lever arm, and started tightening the bolts on one side.

Tighten one bolt so that it's firmly set.   Now tighten the other bolt so that it is firmly set.   

Now go back and check the other one.   OOPS, it's loose now, tighten it so that it's firmly set.
Now go back and check the other one.   OOPS, it's loose now, tighten it so that it's firmly set.
Now go back and check the other one.   OOPS, it's loose now, tighten it so that it's firmly set.
Now go back and check the other one.   OOPS, it's loose now, tighten it so that it's firmly set.
Now go back and check the other one.   OOPS, it's loose now, tighten it so that it's firmly set.

You can see where this is going.   This sequence doesn't stop until the clamp is about broken, or so tight that it will break under the bumps of a ride, and you've never put more than a few inch-pounds on an INDIVIDUAL bolt.

Same will happen with a torque wrench.   At some point, you have to have the willpower to STOP even though you could put some more torque on the "other" bolt after you tighten one and still not exceed the spec.

For me, I clean the threads, apply Loctite blue, set each one in place and give them a little pull, then leave them alone - don't go back and "check" the last one .... No broken clamps .....

Lannis

[normzone]

I respect all your viewpoints - the geometry would make welding challenging, and castings can be problematic for welding. That said, you should locate a trained and experienced welder and ask their opinion.

There are professional welders who work miracles daily with improbable alloys and complex geometries. If one of them advises against it I'd respect their opinion. If one of them says " Oh, that's not as difficult as you might think " that's a different ball game.

[John A]

Probly cost more than new parts, who did the pre buy inspection?

[catneck]

Probly cost more than new parts, who did the pre buy inspection?

That would be me.
I trade bikes frequently.
Never had to look for this before.
Lesson learned.

Thanks for all the input.
Really curious about later NTX fork fitment.
Does that unit use the same axle pinch arrangement?
Will be calling Curtis later today.

[oldbike54]

I respect all your viewpoints - the geometry would make welding challenging, and castings can be problematic for welding. That said, you should locate a trained and experienced welder and ask their opinion.

There are professional welders who work miracles daily with improbable alloys and complex geometries. If one of them advises against it I'd respect their opinion. If one of them says " Oh, that's not as difficult as you might think " that's a different ball game.

 The problem with welding this type of casting is the porosity of the base metal . Sure , it can be TIG welded , and will be cosmetically fine , but when bending stresses are applied , the base metal will crack just outside of the weld seam . It is difficult to relieve and heat treat cast aluminum/mag alloys . This is a VERY important component , kinda like brakes or tires , the risk of failure is simply to high . That said , Chuckie hasn't weighed in yet , and he probably knows more than most about this . Yo Chuck , any ideas ?

[Lannis]

That would be me.
I trade bikes frequently.
Never had to look for this before.

You wouldn't have been expected to look for and find something like this.   The only ones who would are those of us that are already aware that it's a potential problem, have seen it happen with other bikes, and would know to get down and look close and rub around and find the crack.

Some Guzzi EV steering heads cracked in the early 2000s, but you'd be unlikely to find it on a pre-buy inspection unless you knew to look for it ....

Lannis

[John A]

I consider it the price of knowledge , unfortunately that was an expensive lesson but at least it wasn't  me!

[Peter from Sch'dy]

Ducati aluminum swingarms cracked and were weld repaired routinely. Steel frames cracked and were scrapped routinely..

YMMV
Best,
Peter