CHECK THIS BOLT!!

[JPC56]

I pointed this out to my dealer bearing in mind that they replaced the bolt and alloy bracket under warranty and the reply was that is unfortunately how they are and they have no issues with it.

 

[TeeTwo]

I pointed this out to my dealer bearing in mind that they replaced the bolt and alloy bracket under warranty and the reply was that is unfortunately how they are and they have no issues with it.

Well, my warranty claim has been submitted which requires the OEM bolt to be part of the repair claim. The bracket is only a $15 part, so there is no sense in spending money on removing the broken bolt, except that part isn't expected to arrive until 'mid-November'.

They saw no reason to stop riding, and I guess if the cat mount and the bracket were perfectly aligned that bolt would carry very little weight given the one-piece construction to the silencer connection with the foot peg hanger. FYI - I was advised that any consequential claims would potentially be challenged if I had an aftermarket silencer fitted.

Anyway, I related your experience and showed them the picture of the deforming bolt on your repair and started to quote the familiar 'doing the same thing twice...' which the service manager finished with '...and expecting a different result is the definition of insanity' ... I'm hoping we have an understanding.

We shall see what evolves.

Will update in due course.

T2

 

[Dave H]

Well, my warranty claim has been submitted which requires the OEM bolt to be part of the repair claim. The bracket is only a $15 part, so there is no sense in spending money on removing the broken bolt, except that part isn't expected to arrive until 'mid-November'.

They saw no reason to stop riding, and I guess if the cat mount and the bracket were perfectly aligned that bolt would carry very little weight given the one-piece construction to the silencer connection with the foot peg hanger. FYI - I was advised that any consequential claims would potentially be challenged if I had an aftermarket silencer fitted.

Anyway, I related your experience and showed them the picture of the deforming bolt on your repair and started to quote the familiar 'doing the same thing twice...' which the service manager finished with '...and expecting a different result is the definition of insanity' ... I'm hoping we have an understanding.

We shall see what evolves.

Will update in due course.

T2

I have taken the precaution of keeping a little penetrating oil on the bolt to help the hanger slide as it expands. 2500 miles with no issues ( fingers crossed )

 

[TeeTwo]

I have taken the precaution of keeping a little penetrating oil on the bolt to help the hanger slide as it expands. 2500 miles with no issues ( fingers crossed )

I hadn't done that and see no reason not to (silicone given the heat down there & water resistant), though I don't believe it would have prevented the failures (JPC56 & mine).

Obviously, I don't know the design criteria and the load the engineer expected this bolt to carry (if any, if the presumption was perfect alignment). As JPC56 showed without a bolt, his hanger is offset left to the bracket. Mine is dropped, straight down 2-3mm, offset left ~1-2mm, as seen below.

View attachment 32505

The load on the bolt will be different between our two copies; no two bikes are going to be identical in this respect. But when a bolt shears it is understrength for the task being asked of it.

I removed the bracket (after the warranty claim was filed) since it was doing nothing useful, so I could take a look. I extracted the bolt, confirmed it was steel and sized a replacement (M8x60 1.25 pitch, grade 12.9). The OEM bolt sheared where the threads in the bracket start, and the extracted stub was all threaded. The opening of the bracket is 9mm, the threads start about 2-3mm into the mount.

View attachment 32506 View attachment 32507 View attachment 32508

The third picture shows the bolt fully seated, and it would be better IMO if the unthreaded shaft was inside the mount (maybe the OEM bolt is).

The bracket was fiddley to remove (from the RHS with the bike on the side stand). The M6 mounting bolts are precoated with blue loctite, and were a little resistant to break free, plus there isn't a whole lot of room to work. The swing arm shaft sits between the upper and lower M6 mounting holes, the bolts go into the engine case.

View attachment 32511 View attachment 32512
Lower Upper

Once the M6 bolts are out the bracket drops down and is easily removed to the RHS.

Reinstall is the reverse, added a drop of blue loctite to the M6 (steel) bolts and exercised care, and went slowly to make sure I didn't cross thread them into the alloy case; it is too tight a space to thread them on by hand, so I used a small 5mm hex key until they were well engaged.

The torque spec is in the attached PDF, and wide (10nm+/-2). I set 9nm, with thread locker on them I saw no reason to go higher.

The bike went on the center stand so a platform scissor jack could be used to raise the cat box to align the mounting holes. When properly aligned the M8 bolt is easily hand threaded pretty much all the way until it hits the seat. If it gets tight during insertion raise or lower the jack in small increments. It is obvious when at the sweet spot. No loctite on the OEM threads, I didn't use it either (with the bolt under shear stress it is unlikely to back out anyway).

The M8 was snugged down, the space is too tight to get my torque wrench in, after snugging it down I measured the gap, it was just under 5mm (the minimum gap spec). I backed the bolt out slightly to hit 5mm (about 1/8 of a turn)...and marked the bolt with a dot of paint so I can easily see if it is rotating. Job done. And gave it a shot of silicone into the sleeve per Dave H.

View attachment 32510

250 miles on it today. All good...and far better than riding it around while waiting for the warranty bracket & repair.

The bolt only cost $2.65 (Home Depot). It is easy to get in and out and I plan to check it periodically until I hit 7,500 miles. Hoping it holds up, and if it does, I will replace it and continue to do so at every future service. Cheap insurance against it failing while on the road.



T2.

 

[VernonT]

I was double-checking fit with the side case during Mistral exhaust install today and noticed that the main bolt which supports the CAT dead center behind the transmission was backed out around a half inch. That struck me as "odd." It also lacked the telltale yellow paint splash indicating recheck at the factory. I checked it (6mm allen and ratchet) and found that it was indeed loose. It screws into a blind threaded cast boss on the underside of the transmission case. This picture identifies the bolt, already tightened with as much torque as a prudent man would apply, and you can clearly see that the fastener is about 6mm too long for its intended job. (Rear of the bike is the left side of the pic, view from the right side of the bike

EDITED: LEAVING THIS POST HERE FOR CONTEXT, AND AS OTHERS MIGHT WONDER WHETHER THIS BOLT SHOULD *APPEAR* TO BE OVERLY LONG. CHECK YOURS ANYWAY ! THOUGH IT'S SUPPOSED TO BE LONG ENOUGH TO ALLOW FOR EXPANSION, MINE HAD INDEED VIBRATED LOOSE AND BACKED OUT AN ADDITIONAL 10-12 MM. CORRECT INFORMATION IN SUBSEQUENT POSTS.

I will be removing and replacing it after shortening it appropriately, but it clearly had vibrated about halfway out in just 200 miles or so of riding, so y'all might want to give yours a peep. (**This is the wrong solution!! see below for more information.**)

View attachment 29767

I checked mine a few days back. The bolt had literally backed out completely, absolutely no thread contact.
I re-tightened to the 25nm called for. So far so good but will certainly add to my list of “pre/post flight” checks. That and the loose right front abs rotor.

 

[Ranishdogs]

Hi everybody , was checking over bike this morning and found bolt holding cat on was missing , I had checked it a few weeks ago and it was still there . Going to contact Jim Allan and see what's his take on it .

 

[Tebax]

I just checked mine, and it’s positioned as it should.
Seems straight enough too.
Dunno if the dealer checked it in the first service but I very much doubt it as it wasn’t a general issue (and still isn’t although some have had problems).

 

[Ranishdogs]

Removed cast brkt as I could get new bolt to start . Found bolt had sheared off just inside casting . Contacted Jim Allan's and they want bike back into workshop as no warranty would be granted without them having tge bike physically in . Although after having sent more photos they say warranty will not be a problem . See attached pictures . Interestingly when trying to get new bolt in I hadxto loosen the header pipes on head to gain a bit of movement ad there was a lot of strain on cat brkt .

 

[TeeTwo]

Hey Ranishdog - welcome to the sheared bolt club and thanks for adding to the knowledge base. Mileage?

The header pipe/exhaust manifold/cat assembly is long, and the cat bracket is towards the rear, the assembly and cat bracket are welded. It is easy to understand how a slight misalignment to a fixed point on the cast bracket boss could occur. I was fortunate not to have to loosen the header pipe (using the platform jack did the trick with just hand turning the jack, so not much stress applied to the assembly on my unit to get alignment.)

Obviously, this is not a general problem; the majority have not had an issue, some bolts have sheared when the assembly is under stress, others have worked loose (and presumably were simply retightened or replaced, under little stress & reasonably aligned, no need to jack the box or loosen the header pipes).

Thinking out loud..

...I guess the header & hanger bolts are all threaded when the exhaust assembly is presented to the bike, engine in frame, then tightened to torque; when fully torqued out any misalignment stress will reveal itself mostly on the itsy-bitsy hanger bolt. I also wonder if that is why the threads on the boss are recessed a touch and the mouth is 9mm, to aid getting the hanger bolt in place?

Seems like a classic distribution bell curve at work. Most will be 'misaligned' enough to keep the bolt in and not 'misaligned' sufficiently to stress the bolt to shear. I also wonder if the # of heat/cool cycles will be influential?

Worried about the bolt working out? - marking the bolt with a paint dot/indelible marker is an easy reference point for movement, take a look down every time you pull the bike out. Using thread locker may not work very well given the heat through that bolt.

If it sheared, up strength the replacement bolt, what is the worst that could happen? It shears again or the casting fails (and it looks like a pretty solid casting). The assembly welds aren't likely to fail etc. Cracked/failed silencer attachment as some have had? Regardless, using the same OEM bolt without any other adjustment doesn't make sense to me; JPC56's ongoing experience teaches that IMO.

I'm looking forward to learning how your dealer takes care of this.

Cheers. T2

 

[Ranishdogs]

Hey Ranishdog - welcome to the sheared bolt club and thanks for adding to the knowledge base. Mileage?

The header pipe/exhaust manifold/cat assembly is long, and the cat bracket is towards the rear, the assembly and cat bracket are welded. It is easy to understand how a slight misalignment to a fixed point on the cast bracket boss could occur. I was fortunate not to have to loosen the header pipe (using the platform jack did the trick with just hand turning the jack, so not much stress applied to the assembly on my unit to get alignment.)

Obviously, this is not a general problem; the majority have not had an issue, some bolts have sheared when the assembly is under stress, others have worked loose (and presumably were simply retightened or replaced, under little stress & reasonably aligned, no need to jack the box or loosen the header pipes).

Thinking out loud..

...I guess the header & hanger bolts are all threaded when the exhaust assembly is presented to the bike, engine in frame, then tightened to torque; when fully torqued out any misalignment stress will reveal itself mostly on the itsy-bitsy hanger bolt. I also wonder if that is why the threads on the boss are recessed a touch and the mouth is 9mm, to aid getting the hanger bolt in place?

Seems like a classic distribution bell curve at work. Most will be 'misaligned' enough to keep the bolt in and not 'misaligned' sufficiently to stress the bolt to shear. I also wonder if the # of heat/cool cycles will be influential?

Worried about the bolt working out? - marking the bolt with a paint dot/indelible marker is an easy reference point for movement, take a look down every time you pull the bike out. Using thread locker may not work very well given the heat through that bolt.

If it sheared, up strength the replacement bolt, what is the worst that could happen? It shears again or the casting fails (and it looks like a pretty solid casting). The assembly welds aren't likely to fail etc. Cracked/failed silencer attachment as some have had? Regardless, using the same OEM bolt without any other adjustment doesn't make sense to me; JPC56's ongoing experience teaches that IMO.

I'm looking forward to learning how your dealer takes care of this.

Cheers. T2

Hi T2 , mileage is only 650 miles . I've got a couple of 10.8 high tensile bolts in stock so will probably just repair myself . Its a 600 mile round trip to Jim Allan in Falkirk and the weather has been pretty crap so unless I can get it done at same time as first service it doesn't make sense to go down . The misalignment on mine was definitely causing a lot of stress on bolt so when I refit it I will slacken off everything and try to get it more in line . Love the bike and have had Guzzi for years so unlike other motorcyclists can live with a little tech faux pas .

 

[viewpoint]

Hi all, Good write up regarding bolt. So I pinched your idea and marked up bolt with paint
Bikes now done 1150 miles. Bolt was very tight so happy with that and the bolt looks perfectly aligned
Dave

View attachment 32524

 

[TeeTwo]

Love the bike and have had Guzzi for years so unlike other motorcyclists can live with a little tech faux pas .

I hear ya. My third Guzzi; I knew what I was buying. It certainly helps to be willing, able & confident enough to tackle the simpler repairs in view of the thin dealer network and extended lead times on parts (though I think they are improving on that front).

At purchase my current dealer/owner said 'If there is a problem with a new Guzzi you will know it in the first 1,000 miles' - she is pretty much on point.

At purchase my wife said 'Why? Guzzi's don't make you happy' - but they do, and the V100 pushes my buttons. Rideable art. (It helps that I'm now retired, getting home from a long loop ride for work on Monday isn't the issue it was, plus I'm lucky to have 3 rides to quench the grumps.)

Oh, and I will stop whining about my 50-mile return journey to the dealership, you made my day.

Ride on and hope you get some autumn weather to enjoy it.

T2

 

[JPC56]

Brief note, my bolt sheared at 720 miles and was replaced at 1351 miles so it survived 631 miles without support. I have now done 2038 miles and the bolt is still there ever so slightly bent but no cracks evident (still not convinced though) If the bolts holding the mounting bracket to the back of the gearbox shear that would be a very expensive warranty claim!

 

[TeeTwo]

If the bolts holding the mounting bracket to the back of the gearbox shear that would be a very expensive warranty claim!

Fair point, if that was to arise as a mode of failure.

If you have a second failure, I wonder what your dealer and MG would do next? Surely not a third install of an identical set up.

We likely will have three set-ups on the go. New OEM on yours, a 10.8 (Ranishdogs) and 12.9 on mine, so we are going to learn something in the next month or two.

Onward. T2.

 

[John in PA]

Hopefully (wishfully?), Guzzi has noted the frequency of failures and will come up with a retrofit improvement.

Breath: not holding...

 

[moparnut72]

I just read through this thread. I am brand new to the Mandello, a week now, so my experience with the bike is virtually zilch. But reading all of this and looking at the photos I think the issue stems from the cat box, catalytic converter. There is a lot of heavy welding in the construction of this component. I would expect that there may be a lot of deformation and warpage in the construction of this part, most likely obtained from an outside vendor. I am guessing Guzzi engineers designed these parts to account for the variations in the converters. I think a hardened stud or a hardened bolt with the head cut off and double nutted may be a good solution and if off centered grinding out the hole on the bracket may help in preventing future problems.

I have owned a couple of brand model vehicles in the past, the first R75/5 in Denver being one. teething issues can and should be expected. It is beyond my imagination to understand what has to be done to design and build a new product as complicated as this bike. Niggles such as this being so far and few between is amazing in itself. As soon as I am out and about I will go out and take a look at mine.
kk

 

[GTM®]

Just eliminate this headache.
As a note, if I ever build one, I would NOT put the trans mount on mine. It's not needed when the boat anchor hot-box is removed.

Agostini V100 SS Header System

Agostini V100 SS Header System Agostini's "big bore" cat-less headers and Y-pipe for your V100 (standard and S models) - Fit to stock or aftermarket (Ago) mufflers linked below. Hand-made with high quality stainless steel. Though claimed to work on stock fueling, we highly recommend the UpMap...

gtmotocycles.com

 

[Ranishdogs]

Good afternoon to all , as an update to sheared bolt I contacted Jim Allan's and they did agree that I would get warranty no problem . Only down side is they need to have the bike in workshop to start warranty process . Due to distance to dealer and the fact I would have to go back once its approved I have repaired old one and ordered new part myself thro Jim Allan . Brkt , 2 x bolts to hold to gearbox and main bolt was £29.90 . No big deal this time but obviously if it was anything big then a different story . . I know I didn't have to order brkt but I like to have spare to hand . The bolt definitely sheered due to misalignment of the whole exhaust , particularly at the header to head junction. . When refitting loosen everything and line up then tighten a wee bit at a time each bolt and check strain . Mine definitely had a lot of side force on cat bolt . Indecently the dealer had not had any other failures or reports of failures but has said he will check everyone at pdi and service from now on .

 

[TeeTwo]

Good afternoon to all , as an update to sheared bolt I contacted Jim Allan's and they did agree that I would get warranty no problem . Only down side is they need to have the bike in workshop to start warranty process . Due to distance to dealer and the fact I would have to go back once its approved I have repaired old one and ordered new part myself thro Jim Allan . Brkt , 2 x bolts to hold to gearbox and main bolt was £29.90 . No big deal this time but obviously if it was anything big then a different story . . I know I didn't have to order brkt but I like to have spare to hand . The bolt definitely sheered due to misalignment of the whole exhaust , particularly at the header to head junction. . When refitting loosen everything and line up then tighten a wee bit at a time each bolt and check strain . Mine definitely had a lot of side force on cat bolt . Indecently the dealer had not had any other failures or reports of failures but has said he will check everyone at pdi and service from now on .

Thanks for the update. Did you fit the higher tensile bolt on your current fix?

I have added 1,200 miles since doing my fix. So far so good, though the bolt had rotated out about 1/4 of a turn. I was going to take it out today, however, I got notice from GTM this afternoon that my Matris monoshock is being delivered 10/16; I will take the hanger bolt out & inspect when I install the shock. With the shock out it should allow room to get the torque wrench on the hanger bolt. I have a replacement 12.9 bolt on hand.

The M6 bolts and the casting checked with a mirror; all good.

Sad to report inflation has bitten, the M8x60 1.25 pitch 12.9 has gone up 10 cents in two weeks, now $2.75. Making the GTM Ago SS assembly slightly more appealing .

BTW I was looking at the torque tolerances on high tensile bolts. An M8x60 8.8 has a torque reco of 24Nm un-lubed, same as MG's spec on the hanger bolt. The OEM was hardened steel, so I'm presuming it was an 8.8.

T2

 

[Ranishdogs]

Thanks for the update. Did you fit the higher tensile bolt on your current fix?

I have added 1,200 miles since doing my fix. So far so good, though the bolt had rotated out about 1/4 of a turn. I was going to take it out today, however, I got notice from GTM this afternoon that my Matris monoshock is being delivered 10/16; I will take the hanger bolt out & inspect when I install the shock. With the shock out it should allow room to get the torque wrench on the hanger bolt. I have a replacement 12.9 bolt on hand.

The M6 bolts and the casting checked with a mirror; all good.

Sad to report inflation has bitten, the M8x60 1.25 pitch 12.9 has gone up 10 cents in two weeks, now $2.75. Making the GTM Ago SS assembly slightly more appealing .

BTW I was looking at the torque tolerances on high tensile bolts. An M8x60 8.8 has a torque reco of 24Nm un-lubed, same as MG's spec on the hanger bolt. The OEM was hardened steel, so I'm presuming it was an 8.8.

T2

Hi T2 , I have not fitted the high tensile bolt yet . On trying to drill the broken old bolt out and not having a drill press I didn't get it entirely straight . The old bolt seemed to be much harder than a standard bolt , I ended up using cobolt drills for s/s . Anyway I've ordered a deep helicoil and will put it in a drill press to straighten the hole . On removing the allen bolts holding the alloy brkt to the engine , one bolt got a bit chewed on head [access is tight and held in by torque seal ] so I ordered 2 x new bolts . Lesson learned so drill press ordered .