CHECK THIS BOLT!!

[keremarsan]

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

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.

View attachment 29767

Hi John , after your post , I checked mine. And this screw is the same as yours , 5-6 mm distance .... I try to tighten, was already full tight ... So I think , maybe , when the bike accelerates , decelerates and with heat , maybe the Exhaust system need some "free moving space " , an error with this size could not be possible in my opinion , maybe some flexibility needed in exhaust system ? I don't know ... I will go to the service they can check it ... thanks for sharing !

 

[scott_m]

…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…

Ugh. For the millionth time. The men who work at and run Moto Guzzi are not a collection of wine infused country bumpkins. They are not stupid.

They are excellent and highly skilled engineers and designers and assemblers and most have worked at the factory for many years.

So now you need to buy a new bolt and put it back the way it was. It didn’t vibrate out and wasn’t wrong. It was INTENTIONALLY engineered this way for thermal expansion.

 

[John in PA]

Ugh. For the millionth time. The men who work at and run Moto Guzzi are not a collection of wine infused country bumpkins. They are not stupid.

They are excellent and highly skilled engineers and designers and assemblers and most have worked at the factory for many years.

So now you need to buy a new bolt and put it back the way it was. It didn’t vibrate out and wasn’t wrong. It was INTENTIONALLY engineered this way for thermal expansion.

The men at Moto Guzzi, though not stupid, ARE human, and not immune to error. Apparently you missed my "Mea Culpa" several posts back where I found and quoted (with photos!) the service manual, with the instruction and torque settings for the bolt, clearly stating that *I was wrong*, and the manual stated that the long bolt was purpose-chosen.
I think I was pretty plain in my explanation, and my confession of error, and that I removed the bushing and corrected the torque on the bolt, which WAS loose BTW, and HAD BACKED OUT well beyond it's correct position, which was how it captured my attention in the first place.

Lighten up just a touch, per favore...

 

[keremarsan]

The men at Moto Guzzi, though not stupid, ARE human, and not immune to error. Apparently you missed my "Mea Culpa" several posts back where I found and quoted (with photos!) the service manual, with the instruction and torque settings for the bolt, clearly stating that *I was wrong*, and the manual stated that the long bolt was purpose-chosen.
I think I was pretty plain in my explanation, and my confession of error, and that I removed the bushing and corrected the torque on the bolt, which WAS loose BTW, and HAD BACKED OUT well beyond it's correct position, which was how it captured my attention in the first place.

Lighten up just a touch, per favore...

Moto Guzzi published a service inquiry about this bolt if Loosen !!! I see that paper, but not take a screenshot and can not find again ??!! , it concern only to check the torque of the bolt !

 

[scott_m]

The men at Moto Guzzi, though not stupid, ARE human, and not immune to error. Apparently you missed my "Mea Culpa" several posts back where I found and quoted (with photos!) the service manual, with the instruction and torque settings for the bolt, clearly stating that *I was wrong*, and the manual stated that the long bolt was purpose-chosen.
I think I was pretty plain in my explanation, and my confession of error, and that I removed the bushing and corrected the torque on the bolt, which WAS loose BTW, and HAD BACKED OUT well beyond it's correct position, which was how it captured my attention in the first place.

Lighten up just a touch, per favore...

Apologies if you were offended. Not my intention at all.

I said this in another thread recently: “Most people are always way to quick to judge me because I’m not a glossy writer. They think I’m being mean or harsh or whatever…

I know, I know, it’s just my bizarre autistic way about myself. I am what I am.”

My point was not directly specifically at just you.

Unfortunately, as most never come here to write how much they love their motorcycle, we only see complaints for the most part. A great many of them are unfounded complaints which is how I interpreted yours.

That being said, one of the goals here at GuzziTech since it’s inception, Todd has truly worked tirelessly to do everything in his power to make sure that this is a forum of real, valid, dependable information and the rest of us long timers try to support him by working towards that goal. We do not want a collection of innuendo and false information.

I hope you can see both sides and realize my intentions. Again I apologize if you were hurt by my words.

Best wishes!

 

[keremarsan]

Here.View attachment 30377

Thank you , appreciate that John !

 

[keremarsan]

Here.View attachment 30377

This bulletin also make clear the subject of why the screw is long ... as Scott mentioned ...

 

[GTM®]

In looking at it, it's a head-scratcher that something that has a rubber isolation bushing would need space for expansion. That said, I look forward to eliminating the heater-plug box and feeding one some fuel.

 

[Burke]

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 was doing a quick nut & bolt check before my planned extended ride this next week and spotted exactly what you have ewarned us about.
It's a bugger to get at, but I did find that it wasn't loose at all..... very tight but needs a spacer or a shorter bolt. I can provide a pic if needed, but it would be exactly same as your picture.
As far as easy access, I think the CAT has to be removed.

 

[heyzeus]

I was doing a quick nut & bolt check before my planned extended ride this next week and spotted exactly what you have ewarned us about.
It's a bugger to get at, but I did find that it wasn't loose at all..... very tight but needs a spacer or a shorter bolt. I can provide a pic if needed, but it would be exactly same as your picture.
As far as easy access, I think the CAT has to be removed.

The dealer told me the bolt is designed this way from the factory. Leave it alone!!!!!!!!!!!

 

[Burke]

The dealer told me the bolt is designed this way from the factory. Leave it alone!!!!!!!!!!!

Thanks heyzeus for the warning.
I have since downloaded the V100 manual to double check if any other fasteners that visually look a bit "off". You shpould howver check your keyboard. The exclamation key sticks!

 

[JPC56]

Checked my exhaust today and this support bolt is missing, it was there yesterday but on returning from a 30mile run the bolt had gone. The bike has only done 720 miles and on closer inspection it seems like the bolt has sheared about 2mm into the threaded boss. it also appears that the exhaust mounting is off set to the left from the engine support mount by about 1-2mm.

 

[John in PA]

Well, that's, ummmm, "troubling..." Still seems an odd, half-baked solution to me. Better to have a horizontal steel hanger off the frame, rubber bushing in a steel sleeve in the CAT, allowing it to "crawl" back an forth to it's heart's content, without losing support, rather than asking a bolt to do a service (perform as a hanger) that it really wasn't designed to perform. But hey, I'm a veterinarian, not an engineer, so what do I know...

 

[JPC56]

Further to my bolt shearing off, I had it replaced along with the cast alloy bracket. The technician showed me the old and new brackets and the old one had clearance for the swinging arm pivot and the new one did not despite both having the same part number cast into them. New bracket ground to match old one and painted. Still not happy about the slight misalignment causing a shear force on the new bolt. Time will tell.

 

[heyzeus]

Thanks heyzeus for the warning.
I have since downloaded the V100 manual to double check if any other fasteners that visually look a bit "off". You shpould howver check your keyboard. The exclamation key sticks!

It was emphasis as some OCDers are not listening

 

[Burke]

It was emphasis as some OCDers are not listening

Totally understand....no worries.
FYI. Found no issues with anything after a five day 1850+ ride recently. No regrets at all. Not knowing what to expect with this brand-new machine I packed a ridiculous number of tools that I never had to touch.
Leaving again this Wednesday for a run over the Sierras into NV..... just cloths & tire kit in the bags.

B

 

[TeeTwo]

I'm at ~1,500 miles on my V100 and still do the periodic checks that fasteners are in place and tight. When it was new the bolt on the cat was there and 'normal' in appearance. It was serviced at 930 miles, and was normal when it went in. On my 500 mile walk around today the bolt was gone, got the feeler gauge in and probed the engine case to check it had gone, not broken. Yep, gone.

Nope broken

I decided to check again this morning, lined up the mounts using a platform jack, and calibrated a probe, which suggested part of the bolt was in the engine case - which I could see with a mirror and flashlight. It seems like about 25-30mm of the bolt is in the case, where it sheared off. Not good, hopefully the dealer has a tech who is good at extracting bolts. It looks like a PITA to get to & presume they will drop the exhaust manifold/header assembly off the bike to do it.

Should it have been checked at service (?) per the tech bulletin, maybe not and I didn't look immediately after the service.

View attachment 32419

The box appears to be welded at the front like a brick $hithouse, and not shabby at the rear, no evidence of cracks/failures thankfully.

Gradually figuring out what a tool set for this bike should include...and it is a little more extensive than the one MG provided

T2

 

[JPC56]

View attachment 32452View attachment 32450

 

[JPC56]

Above images show why my bolt sheared. Top image shows how the new bracket and bolt are under strain. I'm not convinced that it will last very long, it already appears to be bending.

 

[TeeTwo]

Thanks so much for posting, with pictures. I will show those to my dealer today.

I agree with your assessment, that bolt is yielding for sure. If it was a straight replacement bolt why wouldn't it? I have the same concern and am thinking of asking the dealer to use a grade 12.9 bolt with MG consent, on the assumption the OEM is grade 8.8, or 10.9. This would increase the yield strength by ~50% or 30% respectively. Given the bolt thread goes into a replaceable mounting bracket (not directly into the engine case as I had originally thought) I don't see why they would object. If a 12.9 bolt fails MG would need to find a different solution.

I will update here as events unfold.

Thanks again and also for replying to my PM.

Cheers T2