CHECK THIS BOLT!!

[TeeTwo]

Here's my update at 2,698 miles, about 1,300 on the 12.9 high tensile bolt....

View attachment 32798View attachment 32799

... fail. It sheared in the same spot as the OEM, though it hadn't yet departed the housing (I guess that is why it looked to have backed out a 1/4 turn. The bracket and M6 bolts are fine.

So, Ranishdogs, your approach of slackening the header, slip on bolt and rear footpeg mounts, installing the cat bolt (and I see no reason not to continue with a 12.9 - and buy a spare bracket, cheaper then the labor of extracting the stub end) and snugging down the header & hanger fasteners bit by bit is worth a shot. If it takes some of the stress off the bolt it would be beneficial, then tighten off the rear end fasteners.

I will leave it be now and wait for the dealer to install the warranty repair, then do the adjustment myself. What a PITA!

T2.

 

[Ranishdogs]

Hi all , update on bolt . Parts,arrived from dealer and bolt is stamped 12.9 so it is a high tensile one . Dont know of its been updated or original was 12 .9 all along .

 

[Ranishdogs]

Here are pictures of bolts , silver one from Guzzi .

 

[Ranishdogs]

Here are pictures of bolts , silver one from Guzzi .

Another update , tried to fit new brkt supplied by Guzzi but would not fit . Same part no but different part ,it fowls the swinging arm spindle . See pictures , new on left .

 

[TeeTwo]

Another update , tried to fit new brkt supplied by Guzzi but would not fit . Same part no but different part ,it fowls the swinging arm spindle . See pictures , new on left .

JPC56 reported the same issue when he had his dealer warranty fix, see post #35. The dealer ground down the new bracket to relieve the interference.

The mismatched replacement bracket issue is confirmed with your observation. I will advise my dealer when my part comes in.

Thanks for posting this information.

As for the bolt, it looks longer than the reference black 12.9. Were both classified as 60mm? Wondering if MG has done a switcheroo on the length, quality or changed supplier. That new bolt certainly looks different to what I recall my OEM looked like (or John in PA pics in this thread). It was coated but not bright like your replacement.

You can't make this up.

Onward.

T2

 

[Ranishdogs]

Fitting it back on just now , slacken header nuts then fit centre cat bolt and tighten . Then tighten the header flange nuts . The silencer is a bit of a problem as it doesn't seem to line up with rear peg bolt hole . About 1/4 hole off . Alot of twisting silencer back and forth onto cat then rubber mallet to knock fully on . Think there might be alot of strain from silencer to cat .

 

[TeeTwo]

Think there might be alot of strain from silencer to cat .

I hope your refit goes well and holds up.

After my 12.9 (non-OEM) bolt failed I took another look around the whole assembly, and the point quoted above maybe the answer. My misalignment of cat hanger to bracket results from the cat being lower and pushed to the LHS. When I looked at the factory fit between the silencer there is 10-15mm of the cat fitting showing. See pic.

Aside from repeating your steps, I'm going to have the dealer pull the silencer (and use an expander on the silencer fitting if necessary) to hopefully get the cat fitting pushed about 5mm further into the silencer - and tighten it down along with the header pipes. That should have the effect of raising the cat box up and pulling it to the RHS, in the hope it relieves the stress on the cat hanger bolt.

View attachment 32907

If that doesn't work ....I know, I know.... get the ago pipes plus an ECM reflash from GTM (when available) ...but that is a ton of investment to fix Guzzi's issue.

Anyway, I'm sure you will keep the forum posted as things move along, as will I.

Cheers. T2

 

[Ranishdogs]

Back together , time will tell if all good . I'll let you know what dealer says about brkt .

 

[JPC56]

Well, as I expected my hanger bolt has failed again. It hasn't looked right for a while so I tried it with an allen key and it turned fairly easily. Slackened every thing off and removed the silencer/muffler lined up the cat and hanger bracket as close as possible with wooden wedges. replaced the silencer/muffler but left loose including the hanger on the passenger foot peg bracket. Because the cat was offset to the left I tightened ( not to correct torque yet) the right hand exhaust front nut and then the left hand exhaust rear nut followed by the other two nuts. With the silencer/muffler in the correct position the connecting band was tightened up then the silencer/muffler bolts. All bolts and nuts were then torqued up in the same order, the wedges removed and the cat and hanger bracket appear to be lined up correctly. I shall be having a word with the dealer and report on the response.

 

[Ranishdogs]

Good evening all , further to Tee Two's idea about using an exhaust expander on cat pipe I have ordered one and will try it out and let you know if it makes fitting silencer easier .

 

[JPC56]

Spoke to dealer and showed him the broken bolt. More photographs and second warranty claim for same failure going in to MG. I explained how I had realigned the exhaust system as per previous post and he said he would bring this issue up with MG technical people. Maybe it's an assembly problem! (JPC56-clutching at straws dept.)

 

[TeeTwo]

Spoke to dealer and showed him the broken bolt. More photographs and second warranty claim for same failure going in to MG. I explained how I had realigned the exhaust system as per previous post and he said he would bring this issue up with MG technical people. Maybe it's an assembly problem! (JPC56-clutching at straws dept.)

Thanks for posting. I'm still waiting on news from the dealer that the new bracket (requiring grinding to fit) is in their hands. Clearly most V100's don't have the issue we have experienced, though I expect more to arise as time goes on and the stress on the bolt eventually fatigues it to failure, particularly if MG have only recently upgraded the original bolt to a 12.9. Our alignment is just way out of whack; I'm keeping the faith.

My unit now has 3,750 miles on it, the last 1/3 being bolt free. No evidence of any failure/cracking yet on the cat sleeve, which looks to be the weakest part of the entire exhaust structure. I wonder if MG will eventually ditch the cat bolt entirely, if perfectly aligned it shouldn't be carrying much of the assembly weight.

T2

 

[JPC56]

They say it's for thermal expansion but if you look at the coefficient of linear expansion for stainless steel, for the length of exhaust involved, it is measured in thousandths of an inch. The silencer/muffler just has a rubberised mounting. Maybe it seemed like a good idea at the time.

 

[TeeTwo]

The replacement bracket is with my dealer and the bike booked in for repair on Friday. The tech will take the steps discussed here to try and better align the hanger mount with the bracket. We will see how that goes.

I took my extending mirror with me and looked at the bolt installed on a V100 they had on the floor. It was stamped 12.9. No wonder adding what I thought was a higher tensile bolt was doomed to fail, at about the same mileage as before.

 

[GTM®]

This thread was accidentally deleted. If you posted previously, please add the images back in. They were unrecoverable in restoring this thread.

 

[TeeTwo]

Well, my new OEM bracket (yes, it required grinding to fit) and OEM 12.9 bolt are installed. It took the dealership quite a while to do - the service manager said 'the tech is wrestling with your exhaust system' - but they were able to narrow the gap shown by the arrow, by getting the cat tube further up into the silencer tube but not by much, maybe 1-2mm if that. The pic shows the gap prior to the install.



They said the bracket and hanger were better aligned, they were on it a while and the fastener/hanger on the foot peg definitely looks better for the attention. I take it at face value and go ride. If it breaks again - I'm just gonna ride. .

Good luck with your latest install Ranishdogs.

T2

 

[Ranishdogs]

Well, my new OEM bracket (yes, it required grinding to fit) and OEM 12.9 bolt are installed. It took the dealership quite a while to do - the service manager said 'the tech is wrestling with your exhaust system' - but they were able to narrow the gap shown by the arrow, by getting the cat tube further up into the silencer tube but not by much, maybe 1-2mm if that. The pic shows the gap prior to the install.

View attachment 33200

They said the bracket and hanger were better aligned, they were on it a while and the fastener/hanger on the foot peg definitely looks better for the attention. I take it at face value and go ride. If it breaks again - I'm just gonna ride. .

Good luck with your latest install Ranishdogs.

T2

Hi all , finally had time to put the new theory to practice . Exhaust expander arrived so took off silencer and tries it , first attempt failed as the expander only opened up the flutes at end of can . Bit of a think and found an old clamp that was near the same size so put that on one side of expander and the other into can and yes it did open up a bit with a good bit of pressure on tool . I also realised that inside the can intake pipe there was a weld that had penetrated by about 2 to 3 mm for about an inch and half . I decided to grind this down with a small burr tool and managed to get it quite smooth . Refitted can to cat and it fitted easier and lined up better than before so time will tell .

 

[Ranishdogs]

Good day , has anyone any feed back about mod . All seems to have gone guiet.

 

[TeeTwo]

Good day , has anyone any feed back about mod . All seems to have gone guiet.

I have only put ~500 miles on since the dealer warranty installation. So far the new bolt has remained in place, but it is too early to tell if it will stay that way. I will report back when it has 1,500 on it, or sooner if it snaps!

T2

 

[JPC56]

Update on my second warranty claim for the bolt failure. Today the dealer received two exhaust gaskets (copper) one bolt and a bracket. Agreed to have them fit the parts (if it fails again I am still covered). We noted that the new bracket will need to be modified to fit. Apparently MG say this part has now superseded the original. Why supersede a part that fits the bike with one that needs modifying to fit!!!