V7 II shaft failure

[lorengo70]

Hi there. My V7 II with 40k miles on the clock suddenly lost all power to the rear wheel while on the highway last week.  There was no heads up prior to that incident. I never changed the rear tire myself before so I never did shaft maintenance myself. I would tell the mechanic to grease the spline(so I assumed he did I every time). So that’s the bikes history. This weekend I took the bike apart and the  damage is worse than I expected. Pinion on final drive bevel box has been shredded. Coupler also worned and scored. Shaft and u-joint rusted. Mushroom at end of shaft worn. The only good news is that the spline coming out of the the tyranny looks OKish (some rust but no play when I insert the coupler).  So, looks like I will need to buy the whole works (bevel box, couplers and shaft). Question for you. Saw a used bevel box from a Milano on ebay in great condition with only 3k km on it at a very good price. A bevel from a V7III should be the same as from a V7 II, right?  Adding some pictures so you can see the damage that water on the shaft can do and why shaft maintenance is so important. Not sure what would cause the splines on the pinion in the bevel box to break like that. I appreciate any thoughts, comments or ideas you guys might have. Cheers. Luciano

[Two Checks]

Yikes! Looks like Luigi forgot the grease and gear lube!

How many miles since the last tire change? If the mechanic was servicing the spines he would have seen something was wrong before the last tire change.

[Murray]

Just wondering if its more related to final drive failure cause the shaft to fail rather than the other way around. Did you have a rear wheel lock up moment when it went? It could be the carrier bearing siezed so the motor snapped the shaft and the foward momentum of the bike chewed up the crown wheel/pinion.

[Antietam Classic Cycle]

Yikes! Looks like Luigi forgot the grease and gear lube!

How many miles since the last tire change? If the mechanic was servicing the spines he would have seen something was wrong before the last tire change.

I'm working on a 2013 V7 Special with 8k miles on it at present - leaky rear drive, front tire, remap. There was moisture inside the driveshaft tunnel/swingarm even though the boot is perfectly sealed. Barely any grease on the splines and what was there had pretty much solidified. All of the seal surfaces had some amount of minor pitting on them.

[SmithSwede]

I think what you are saying is you were going down the highway, the engine kept running, and then the rear wheel started free wheeling.   So what part in the drivetrain is actually broken?  The U-joint?  Or is there a set of splines that are so stripped that power cannot be transmitted?

Did the driveshaft couplings come apart freely?  When mine failed, they were seized together and I had to hammer them apart. 

[sign216]

Just wondering if its more related to final drive failure cause the shaft to fail rather than the other way around. Did you have a rear wheel lock up moment when it went? It could be the carrier bearing siezed so the motor snapped the shaft and the foward momentum of the bike chewed up the crown wheel/pinion.

I like this theory, that there must be something more than just no spline lube for such a dramatic failure.  A lock up, or seizure, something in the drive train, and then a cascading set of failures.

Idk, just an idea.

Joe

[malik]

Very nasty. Note that the drive shaft is the same part number from the V65 right through to the V7 III Racer, but that of the final drive/bevel box changes - it looks like the III has different innards than the earlier versions, (Guzzi hasn't even used the same exploded diagram in its Spare Parts Manuals for the III), so unsure whether the Milano one will fit, though I suspect it might.

Here's a photo of the drive shaft on the V7 Special - a few years previously got caught in the outback with heavy rain in the red bulldust. That stuff turns to glue when wet, sticks on the wheels, scraped off by the mudguards & swingarm. The red clay worked itself past the boot onto the Uni joint & into the swingarm. Sanding & polishing cleaned the unsightly rust from the shaft, but the working surfaces & splines were still greasy & OK - I did keep the grease up to the bottom end.

[lorengo70]

Just wondering if its more related to final drive failure cause the shaft to fail rather than the other way around. Did you have a rear wheel lock up moment when it went? It could be the carrier bearing siezed so the motor snapped the shaft and the foward momentum of the bike chewed up the crown wheel/pinion.

It’s like SmithSwede says, motor running, bike rolling (no lock up) just as if it were on neutral. So, no transmission. That said, I put the bike together again after cleaning the shaft, etc and now the is power going to the rear wheel. It makes a clunky sound coming from the final drive as it goes thru the the broken spline on the pinion. After cleaning the parts I found that the splines in the shaft and coupler are not that badly damaged that it would make it spin on the coupling. The main problem is the final drive which needs replacement. I might not replace the shaft and just get the couplings (referred as hose on the parts catalog). By carrier bearing, are you referring to the the spline coming out of the tranny?

Anyhow, need to figure out if I can fit a V7 IiI final drive bevel on my V7 I because I found a reasonably priced used one. If anybody thinks that’s a go please chime in. Thanks

[Two Checks]

The wear in those pics came about over time imo. I could be mistaken...

[lorengo70]

Very nasty. Note that the drive shaft is the same part number from the V65 right through to the V7 III Racer, but that of the final drive/bevel box changes - it looks like the III has different innards than the earlier versions, (Guzzi hasn't even used the same exploded diagram in its Spare Parts Manuals for the III), so unsure whether the Milano one will fit, though I suspect it might.

Here's a photo of the drive shaft on the V7 Special - a few years previously got caught in the outback with heavy rain in the red bulldust. That stuff turns to glue when wet, sticks on the wheels, scraped off by the mudguards & swingarm. The red clay worked itself past the boot onto the Uni joint & into the swingarm. Sanding & polishing cleaned the unsightly rust from the shaft, but the working surfaces & splines were still greasy & OK - I did keep the grease up to the bottom end.

Thank you Malik for the comments on the III final drive. I  Will have to do more research on it. Woulda love it if it did because I found a fairly cheap one with only 3k miles on it and in perfect condition (problem is it’s in France and just shipping here to Canada is 100 euros so I need to be 100% sure). One this is for certain, once I get my parts that Wurth grease is going to be used like there is no tomorrow at each tire change. Worth taking the swing arm while changing the tire, very little incremental work to do it). Cheers, Luciano

[lorengo70]

Thank you Malik for the comments on the III final drive. I  Will have to do more research on it. Woulda love it if it did because I found a fairly cheap one with only 3k miles on it and in perfect condition (problem is it’s in France and just shipping here to Canada is 100 euros so I need to be 100% sure). One this is for certain, once I get my parts that Wurth grease is going to be used like there is no tomorrow at each tire change. Worth taking the swing arm while changing the tire, very little incremental work to do it). Cheers, Luciano

Malik, looking at the parts catalog at AF1 for both the the III and the II and they are the same going from the shaft to the final drive bevel box. So, I think that I can buy the III bevel box and just put it on my II. Does anybody think I am rerong on this theory?

[malik]

The drive shaft and all the associated bits seem to be the same (throughout the range) but the black bevel box for the 1TB V7 & V7 II is #976941, and for the III is #2B0034845, so some checking is needed before commitment. Even if the colour only is changed, the part number will different. On top of that, Guzzi appears to be re-numbering parts - sometimes they are the same, other times, improved, and yet others some more slight differences. There's a chance that some of the professional mechanics could know more. I'll check with a couple of shops I know (& from whom I'm likely to get more than the time of day) on Monday (tomorrow).

[Kiwi_Roy]

I serviced my V7iii last weekend at 13,000 km and not before time, there was water in the tunnel and first signs of rust, very little grease IMHO it should be serviced at first tire change.
The spline at the gearbox end is quite well protected but the ones at the rear end are designed to take up minor misalignment and will be the first to suffer. In my opinion water leaks in at the front of the boot, the zap strap is kind of "Q" shape at the point where the tail threads through, they were designed for strapping down cables not sealing boots I used a different style of clamp when I put it back, one that has a more even pressure. I also smeared some grease across the surface of the face where the final drive mates to the box, cold water can penetrate the tiniest crack, but water doesn't like a greasy surface.

[lorengo70]

The drive shaft and all the associated bits seem to be the same (throughout the range) but the black bevel box for the 1TB V7 & V7 II is #976941, and for the III is #2B0034845, so some checking is needed before commitment. Even if the colour only is changed, the part number will different. On top of that, Guzzi appears to be re-numbering parts - sometimes they are the same, other times, improved, and yet others some more slight differences. There's a chance that some of the professional mechanics could know more. I'll check with a couple of shops I know (& from whom I'm likely to get more than the time of day) on Monday (tomorrow).

Malik, thanks a lot for checking it out for me. Very greatful for that. The guzzi dealership here in Toronto doesn’t open till Tuesday so I will ask them as well   Cheers

[lorengo70]

I serviced my V7iii last weekend at 13,000 km and not before time, there was water in the tunnel and first signs of rust, very little grease IMHO it should be serviced at first tire change.
The spline at the gearbox end is quite well protected but the ones at the rear end are designed to take up minor misalignment and will be the first to suffer.
In my opinion water leaks in at the front of the boot, the zap strap is kind of "Q" shape at the point where the tail threads through, they were designed for strapping down cables not sealing boots.
I smeared some grease across the surface of the face where the final drive mates to the box as well, cold water can penetrate the tiniest crack, water doesn't like a greasy surface.

Good to know,thanks. Never trusted the rubber boot. From all the related threads posted here the boot needs silicone proofing and the oil pressure vent at the final drive cannot be trusted to not let water into the bevel box.

[Off @ 90]

That is quite a drastic failure. The factory seem to omit greasing some of the splines  on cardan shaft and shouldered pin on swingarm bearings .
For peace of mind I would check splines even on a new bike . They might be greased and all is well but if dry will rust and cause expensive failures eventually . For off road bikes  ie Stornello,V85  this is even more critical  with more  rear wheel movement  and travel plus water  ingress  etc .
 I change  my bevel box oil at same time as engine oil such a small quantity oil and you can check for water too .
All the best for  the repair .

[malik]

Spoke to a couple of Guzzi mechanics so far over here - no direct experience, they think the III bevel box should fit OK, but they wouldn't bet their life on it. So no guarantees until after you put it on & are able to drive off. If I find out differently, I'll be sure to let you know.

[SmithSwede]

Have you had this bike since new?   How many miles did you personally put on it?

I’m baffled about this failure. 

Don’t freak out.  I’m confident you can get this completely sorted, but I’m wondering what the root cause of this problem was. 

Did you save the oil you drained from the final drive?

[lorengo70]

Spoke to a couple of Guzzi mechanics so far over here - no direct experience, they think the III bevel box should fit OK, but they wouldn't bet their life on it. So no guarantees until after you put it on & are able to drive off. If I find out differently, I'll be sure to let you know.

Great, thanks for looking into it Malik. Cheers

[lorengo70]

Have you had this bike since new?   How many miles did you personally put on it?

I’m baffled about this failure. 

Don’t freak out.  I’m confident you can get this completely sorted, but I’m wondering what the root cause of this problem was. 

Did you save the oil you drained from the final drive?

Yes, bought this bike brand new. Problems I had with the bevel box was water somehow getting in (through breather plug?) contaminating the oil and making it look like chocolate milk. On a trip to Pennsylvania last year it overflowed all over the wheel and I drained about 250ml out of it (even though I only put 170 ml in it as per manual instructions). So, no sure if water contamination had to do with it or not(the pinion was still bathed on that water oil concoction so there was no rust whatsoever on the pinion) Also baffled as to how the pinion splines could be shattered like they were. You would almost think that some outside metal made it into the box (not sure how that could happen). I also figured out why the bike lost all power to the rear wheel. There is a circlip in the coupler that binds the shaft to the rear drive spline. That came off thereby unbiding the two ends so the shaft was spinning without proving power to the rear wheel. My theory is that that circlip was designed as a circuit breaker for when something goes awry. Because of the broken pinion, the bevel drive will spin with a jerky motion when going through the broken splines and transferring pressure up to the shaft. Just a theory but someone chime in if they have an alternative explanation as to why there is a circlip on the coupler (called hose on parts manual). Also would love to hear about any theories as to why the pinion splines shattered.

[malik]

Was speaking with Pete Roper - he's put a beer on a lost crown wheel bolt in the bevel box, and we all know how much Pete likes his beer.

[lorengo70]

Was speaking with Pete Roper - he's put a beer on a lost crown wheel bolt in the bevel box, and we all know how much Pete likes his beer.

I suspect that's what happened. Only a piece of metal can shear the splines like that. Once my new (to me) bevel box arrives (ended up buying one from a V7 III with 4k miles on it for $150), I will dissect the old one and find the culprit and post my results here. cheers.   Luciano.

[lorengo70]

That is quite a drastic failure. The factory seem to omit greasing some of the splines  on cardan shaft and shouldered pin on swingarm bearings .
For peace of mind I would check splines even on a new bike . They might be greased and all is well but if dry will rust and cause expensive failures eventually . For off road bikes  ie Stornello,V85  this is even more critical  with more  rear wheel movement  and travel plus water  ingress  etc .
 I change  my bevel box oil at same time as engine oil such a small quantity oil and you can check for water too .
All the best for  the repair .

Thanks Off @ 90. Rust in the shaft was a problem but was not the main reason as to why the bike ceased to work. It was the splines in the pinion and crown in the final drive box that broke off. There is a theory brought up by Peter Roper that one of the nuts inside the box got freed and got grinded away thereby shattering the splines. My bet is on that as well. As far as the rest of the shaft component, as has been discussed here many other times, water seems to sip in thru the rubber boot at the u-joint. Will put grease/silicone on both ends once i get the replacement parts. Will also check the rear drive oil more frequently to make sure there is no water/oil contamination. Thinking of ordering that banjo breather bolt that some ppl have posted here to make sure water does not come in thru there. cheers.

[jpv7]

Sorry to hear about your issue...didn't the shop have the box apart a couple of times for the leaking seal issue (oil on rear wheel)?  As I've not done one myself, I'm not sure how deep you need to go to get to the seal...

BTW - I'm sure riding in the snow didn't have anything to do with it...!

[SmithSwede]

Ah ha.  The circlip was off.   Thanks, this is making more sense to me.

[lorengo70]

Sorry to hear about your issue...didn't the shop have the box apart a couple of times for the leaking seal issue (oil on rear wheel)?  As I've not done one myself, I'm not sure how deep you need to go to get to the seal...

BTW - I'm sure riding in the snow didn't have anything to do with it...!

Hi John, yes, the dealership took that bevel box apart to replace the seal(twice!) as it was leaking while the bike was still under warranty a couple of years ago. Maybe a nut holding the crown was not torqued to the right specs? Who knows, sometimes s*it happens. Will try to find what caused it once the new (to me) bevel box arrives and i can dissect the old one (put the old one back on the bike so i could take it off the lift) Going fwd, if i get a leak on my my new (to me) bevel box, I will open it myself and repair the seal. I also have the broken one here that I can open and use for practice. cheers

[lorengo70]

Ah ha.  The circlip was off.   Thanks, this is making more sense to me.

yes, The ciclip was pushed out oher place by either the shaft or the final drive mushroom head. I suspect that its function is to fail when there is stress inside the coupler (just my theory). That caused the link btw the two ends to come apart and the consequent lack of power to the rear wheel. All this, probably caused by the pinion and crown being chewed up by what most probably was a nut that holds the crown becoming free (still a theory that might be revealed once i open the bevel box). cheers.

[Off @ 90]

Will be interesting to see what let go in bevel box . You are lucky the rear wheel didn't lock up. There are no nuts inside bevel box the crown gear is attached with Allen bolts loctited hopefully .

[lorengo70]

Hi there. My V7 II with 40k miles on the clock suddenly lost all power to the rear wheel while on the highway last week.  There was no heads up prior to that incident. I never changed the rear tire myself before so I never did shaft maintenance myself. I would tell the mechanic to grease the spline(so I assumed he did I every time). So that’s the bikes history. This weekend I took the bike apart and the  damage is worse than I expected. Pinion on final drive bevel box has been shredded. Coupler also worned and scored. Shaft and u-joint rusted. Mushroom at end of shaft worn. The only good news is that the spline coming out of the the tyranny looks OKish (some rust but no play when I insert the coupler).  So, looks like I will need to buy the whole works (bevel box, couplers and shaft). Question for you. Saw a used bevel box from a Milano on ebay in great condition with only 3k km on it at a very good price. A bevel from a V7III should be the same as from a V7 II, right?  Adding some pictures so you can see the damage that water on the shaft can do and why shaft maintenance is so important. Not sure what would cause the splines on the pinion in the bevel box to break like that. I appreciate any thoughts, comments or ideas you guys might have. Cheers. Luciano

An update to my failed final drive. So, I opened the final drive bevel box and a couple of the teeth on the crown pinion were broken. Someone here on the post suggested that it might have been caused by one of the six screws that hold the crown pinion together coming loose and braking the pinion's teeth. That was not the case as all six screws are still attached. So, I would have to attribute the broken teeth to metal fatigue (unless someone else has another theory).

Also, as part of dealing with this problem, I also found that water had come into the shaft creating rust on the shaft and coupling. I was able to source a final drive bevel box from a V7 III (thank you Malik for asking around if it fits on a V7 II. It does, no problem) and all the other components from a ebay. The bike had only 3k miles on it and all the components looked almost new. The other good thing is that the bike was located here in Canada so the shipping costs were about $20. For those who are interested in the cost of this repair; all the parts were CAD$400 (with tax and shipping) or about $300 USD. Here is the ebay link for those of you who might be interested in getting other parts of this bike: https://www.ebay.com/sch/m.html?_odkw=eb777&_ssn=bgpowersports&_osacat=0&_from=R40&_trksid=p2046732.m570.l1313.TR0.TRC0.A0.H0.Xeb770.TRS1&_nkw=eb770&_sacat=0  (prices are in Canadian dollars

Here some pictures of the broken crown pinion (a piece of one of the broken teeth in the bottom of the pic)

Would like to thank you all for your comments and suggestions while I was trying to get this problem sorted. Special shout out to SmithSwede for encouraging me to tackle this problem on my own. 

Cheers, Luciano

[greer]

Thank you for the follow up, I hope you'll let us know how it goes back together.  And thanks for the pictures, seeing those prompted me to order the bolt and fitting needed for the vent.

Sarah