They make something so strong it's basically bomb proof and then..........

[pete roper]

The bevelbox on the CARC system is generally pretty robust. The one Achilles Heel it has is the light preload on the pinion bearings supplied by the nut and the fact that it is held there simply by a lockwasher. For some bizarre reason Guzzi don't Loctite it and if the bearings settle or wear the preload is lost, the nut comes loose and things go pear shaped fairly quickly.

First symptom will be noise from the final drive on the over-run. If you notice this stop riding immediately. Not only could it preceed a catastrophic failure but also if you stop it there and then it may well be possible to save your final drive. I can't stress how important catching it early is.

If you don't and continue to ride the consequences may be terminal. Michael has just stripped Peter Hughes's box after he continued riding it for a while. Unfortunately it's fed bits of lockwasher all through everything and the results are terminal.

Sorry but there's no saving this one.

This is the pinion nose bearing. Most of the other bearings in the box and reactive bridge look much the same.

Now if you do catch it early and there is no crownwheel or pinion damage it is, despite what the factory may try to tell you, quite possible to rebuild the entire reactive bridge and therefore the bevelbox. My guess though is that very few shops would be willing to try it, either because they don't have anyone with the skills or for liability reasons. It's this sort of numbskull 'Built in obsolescence' that makes my blood boil and we won't have a bar of it. We can at least look at your box and tell if it's salvageable and if we can rebuild it you can bet your arse we'll be Loctiting the living Bejasus out of the pinion nut as it's preloaded so the bastard won't be coming undone again!

Oh, and as an indicator that this sort of repair is quite possible my box on my GRiSO played exactly the same trick. I caught it early, cleaned everything thoroughly and didn't even replace any of the support bearings! Just replaced the nut and lockwasher, Loctited and preloaded to about 120 inch pounds on the nut before bending up the tang on the new lockwasher. That was nearly 50,000km ago and it's still running silent and strong.

[pete roper]

Sorry, I used the usual method of posting pics. You'll have to chase them down. It makes my brain hurt.

[fotoguzzi]

I might be doing it wrong but to copy and paste the first link I don't see your pic.

[docc]

11 hours ago, pete roper said:

Sorry, I used the usual method of posting pics. You'll have to chase them down. It makes my brain hurt.

Moderator magic! Images fixed. All you really need to do when posting an image that is hosted (like yours, Pete, on flikr) is right click on the open image and select "copy image location" then paste into your post. Image addresses that begin and end with [img] (BBCode) won't display.

[Goofman]

Yikes!  I remember groaning the last time I learned something from Master Roper.  But, I couldn't sleep till I checked.  And yes, my shock linkage and swing arm bearings were dry.  From the factory.

So, thanks again, Pete.  My '08 Sport's next (30k) service is gonna be epic!

[docc]

So, could this nut be preemptively secured without waiting for the noise? The, no worries?

[pete roper]

Well yes, and no.

The thing is that to tackle it you really need to split the case. Then you need a special peg socket to remove the seal holder and then another peg socket to remove the nut after biffing down the tang on the lock washer. Then you have to replace the lockwasher, apply Loctite to the pinion threads and re-torque the nut to its very low torque figure and lock it. After which you reassemble the CARC.

Is it difficult? Not really, but the consequences of getting it wrong will be horribly expensive and there is no published torque figure, (That I know of.) so I just use the industry standard for these sorts of applications. If you don't know what they are and don't have prior experience it can all be a bit fraught and daunting. Put it this way. If you feel you are technically competent and would have no qualms about tackling a major engine or gearbox rebuild then I'd say probably yes, you could safely do it, (Cue someone to say their four year old does them in his cot at night!). If though you find yourself stressed by doing your valve clearances and changing brake pads? I'd probably advise against trying it. Remember, Piaggio won't sell some parts even to their shops, and suggest that the reactive bridge is 'Non Rebuildable' which would seem to indicate that they think that rebuilding one is beyond the Ken of the average shaved ape employed in a 'Box Shop' dealership. Certainly if anybody does undertake it they do so entirely at their own risk and if the whole thing goes 'Udders Skywards' afterwards they have to be willing to wear the consequences of their own actions.

[Lucky Phil]

3 minutes ago, pete roper said:

Well yes, and no.

The thing is that to tackle it you really need to split the case. Then you need a special peg socket to remove the seal holder and then another peg socket to remove the nut after biffing down the tang on the lock washer. Then you have to replace the lockwasher, apply Loctite to the pinion threads and re-torque the nut to its very low torque figure and lock it. After which you reassemble the CARC.

Is it difficult? Not really, but the consequences of getting it wrong will be horribly expensive and there is no published torque figure, (That I know of.) so I just use the industry standard for these sorts of applications. If you don't know what they are and don't have prior experience it can all be a bit fraught and daunting. Put it this way. If you feel you are technically competent and would have no qualms about tackling a major engine or gearbox rebuild then I'd say probably yes, you could safely do it, (Cue someone to say their four year old does them in his cot at night!). If though you find yourself stressed by doing your valve clearances and changing brake pads? I'd probably advise against trying it. Remember, Piaggio won't sell some parts even to their shops, and suggest that the reactive bridge is 'Non Rebuildable' which would seem to indicate that they think that rebuilding one is beyond the Ken of the average shaved ape employed in a 'Box Shop' dealership. Certainly if anybody does undertake it they do so entirely at their own risk and if the whole thing goes 'Udders Skywards' afterwards they have to be willing to wear the consequences of their own actions.

No way to check it with say a flex boro Pete? To at least see if the lockwasher tabs are intact and not broken or bent. Like I used to do on Jet engines. We used to pull lock tabs out of the Mag plugs from time to time and use a boro to locate and monitor the issue. nice little articulated boro's are fairly cheap these days and I have a nice one I use connected via bluetooth to my Ipad or laptop.

Ciao

[PJPR01]

So this is on Huzo's Norge I presume based on the CARC description, and not something to be worried about on the V11...am I right?

Given Huzo has close to 200K km on his bike, I'm hoping that mine at a paltry 65K km so far should be fine, no unplaced sounds or any indication of a problem so far, but will bookmark this reminder!

Thanks!

[pete roper]

V11 bevelbox is completely different. It's a real 'Weird Harold' design where the pinion is supported in a strange '2-Part/Combination Bearing'. It has a big roller bearing to take the rotational loads and then in front of it a caged ball bearing with a split outer race. I've never seen anything like it in any other application, (Perhaps Phil has?). It's a real exemplar of how Guzzi engineers used to approach some things from completely left field.

No, this particular issue doesn't occur with V11 boxes. Their major weirdness is the fact the pinion nose bearings always get starved of oil and they have that stupid needle roller in the outside of the box where the spindle goes through that will turn into a filigree of rust in weeks if you ride in the rain!

[pete roper]

1 hour ago, Lucky Phil said:

No way to check it with say a flex boro Pete? To at least see if the lockwasher tabs are intact and not broken or bent. Like I used to do on Jet engines. We used to pull lock tabs out of the Mag plugs from time to time and use a boro to locate and monitor the issue. nice little articulated boro's are fairly cheap these days and I have a nice one I use connected via bluetooth to my Ipad or laptop.

Ciao

Oh you can see if it is still tight by peering down the seal holder and poking at the nut with a screwdriver. Problem is unless it is coming loose you don't know if it's still OK or is a poofteenth off loosing its preload!

Arse!

[Lucky Phil]

2 minutes ago, pete roper said:

Oh you can see if it is still tight by peering down the seal holder and poking at the nut with a screwdriver. Problem is unless it is coming loose you don't know if it's still OK or is a poofteenth off loosing its preload!

Arse!

Oh ok. Could you get some Loctite on the nut? You could use some wick in 290 on the nut even drop by drop on the end of a thin screwdriver. It's specifically designed to be applied after a fastener is tightened and it wicks it's way down the threads. It wont tell you if it's lost its preload ( but there's other ways to do that I'm guessing) but it will prevent loosening.

Ciao     

[pete roper]

3 minutes ago, Lucky Phil said:

Oh ok. Could you get some Loctite on the nut? You could use some wick in 290 on the nut even drop by drop on the end of a thin screwdriver. It's specifically designed to be applied after a fastener is tightened and it wicks it's way down the threads. It wont tell you if it's lost its preload ( but there's other ways to do that I'm guessing) but it will prevent loosening.

Ciao     

Done that too. Actually it is possible to remove the front boot and seal holder, (If you have the correct tool.) without splitting the case and then, in theory, you can do the nut and washer + Loctite trick without splitting the cases.

Problem with this is that the boot is retained by a 'Single use' clamp. Now it can be pried out gently and re-used. If you are very careful and smart! This is why Michael has developed a technique that allows him to do it successfully almost without fail when replacing failed pinion seals. Me? Not so much, I always screw it up so I prefer to split the case because then I can clamp the boot with a simple CV joint band when I put it back together. An operation so simple not even I can screw it up!

My modus operandi is to use the green Loctite when doing the initial re-torque of the nut and then I dribble a bit of 290 in from the top. Have I said why I don't want that f*cker coming undone again..........

[Lucky Phil]

2 minutes ago, pete roper said:

Done that too. Actually it is possible to remove the front boot and seal holder, (If you have the correct tool.) without splitting the case and then, in theory, you can do the nut and washer + Loctite trick without splitting the cases.

Problem with this is that the boot is retained by a 'Single use' clamp. Now it can be pried out gently and re-used. If you are very careful and smart! This is why Michael has developed a technique that allows him to do it successfully almost without fail when replacing failed pinion seals. Me? Not so much, I always screw it up so I prefer to split the case because then I can clamp the boot with a simple CV joint band when I put it back together. An operation so simple not even I can screw it up!

My modus operandi is to use the green Loctite when doing the initial re-torque of the nut and then I dribble a bit of 290 in from the top. Have I said why I don't want that f*cker coming undone again..........

Very good Pete. I recently had dealings with a lovely little stainless steel strap around 6 or 8mm wide and probably .2 thick plain finished with a small incorporated fitting on the end I had no idea of its workings. It was a very nice and compact and you slid the end of the strap into the fitting and it held tight as tight. Inside that little end fitting I later found out is a tiny ball bearing that wedges the strap. Is this the style you need? I was later told its the same design as a CV joint boot retainer. Very cool thing. Not reusable though.

Ciao

[pete roper]

3 minutes ago, Lucky Phil said:

Very good Pete. I recently had dealings with a lovely little stainless steel strap around 6 or 8mm wide and probably .2 thick plain finished with a small incorporated fitting on the end I had no idea of its workings. It was a very nice and compact and you slid the end of the strap into the fitting and it held tight as tight. Inside that little end fitting I later found out is a tiny ball bearing that wedges the strap. Is this the style you need? I was later told its the same design as a CV joint boot retainer. Very cool thing. Not reusable though.

Ciao

Nah, nothing so sophisticated. They're just a strap with a couple of bend down tangs after the buckle. You wind them down with a tightening tool, ($25 at 'Wottalottacrap Auto') bend the end over 180, snip the excess length off with the tool and then use the tangs to hold the end back at 180. If you want them tighter? Just wind the band around the shaft twice before tightening.

Hard to explain. Needs a video.