2021. 1250 shaft failure

Maybe if it was a lumpy road the falling and rising of the suspension and telescoping of the shaft might separate the splines from the fd partially once the bolt was missing.

I can’t believe that they won’t replace the final drive. Cost of rebuilding with labour would probably outweigh BMW’s own part cost which is likely a fraction of the price we pay.

knutk said:

I share your questioning of this case.

Header says shaft failure.Yet, the description says that the bolt for the paralever brace came loose.
While riding, there is a lot of tension on this bolt. The bolt is further locked by Locktite. And even in the unlikely event that the bolt should become unscrewed the heavy tension on it would lock it in position. And the weight of the bike would still push on the link-arm and keep it in position. Further, I question that the splines or driveshaft would be ruined, as surely, if the bolt popped out, the rider would notice and stop.

Now, I am aware of the fact that the only thing that exceeds the imagination is the reality.

Time for some pictures....

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If the paralever arm bolt had come out completely and gone unnoticed... then 'the power is wound on' would the final drive not try to separate on torque reaction and pivot back rather than propel the bike forwards...pulling the drive shaft off the front spline (similar to when the rear spline has rusted together and you force the unit apart and it drags the front spline off the gearbox output shaft and snap ring). Once separated it wouldn't go back together on its own.. as the splines need some 'fiddling to reassemble' but the weight of the bike + rider would try to close the final drive unit back together. Giving the impression that the splines had stripped but in actual fact would just not be coupled together on the splines ? Just a thought .
Maybe BMW want to hush it up as it was a new bike ? Who knows.

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Micko123 said:

If the paralever arm bolt had come out completely and gone unnoticed...

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Soo... You think the rear ende practically disintegrates without the rider notice?

My point is, if the bolt pops out, this surely must be noticed by the rider, and then it's a matter of stopping immediately, i.e rolling less than 30 seconds after the bolt popped out. And this roll-out will damage the shaft?
Sorry, I don't buy it...

If there is a story here, I doubt that we have received the full story. The whole chain of events does not make sense.

Picture pls.

knutk said:

I share your questioning of this case.

Header says shaft failure.Yet, the description says that the bolt for the paralever brace came loose.
While riding, there is a lot of tension on this bolt. The bolt is further locked by Locktite. And even in the unlikely event that the bolt should become unscrewed the heavy tension on it would lock it in position. And the weight of the bike would still push on the link-arm and keep it in position. Further, I question that the splines or driveshaft would be ruined, as surely, if the bolt popped out, the rider would notice and stop.

Now, I am aware of the fact that the only thing that exceeds the imagination is the reality.

Time for some pictures....

Click to expand...

Let's hope it's all going to be blamed on Mr Newton and those stupid laws he discovered

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If the bolt falls out completely and the bike isn't put on the centre stand , you may not notice as the weight of the bike closes the the final drive together, until a burst of acceleration is applied which would tend to open the final up... maybe ?

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After 5 pages of he said , she said, my mates said,

its boils down to this

Not sure we will ever know actual cause and chain of events even if the dealer allows pics. As Knut mentioned you can normally feel any knock or vibration in the suspension or drive train through the bike so if the splines were grinding and the fd pivoting open and closed it must have been very obvious.

Rain mode was mentioned so doubt he was going banzai and it all mashed up before he had time to slow etc.

leadfarmer said:

I’ve never heard such an absolute crock of bollocks in my life, not even on here

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Oh I dunno...

Micko123 said:

If the bolt falls out completely and the bike isn't put on the centre stand , you may not notice as the weight of the bike closes the the final drive together, until a burst of acceleration is applied which would tend to open the final up... maybe ?

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But, since the driveshaft is claimed to be damaged, the final drive must collapse quite a bit, and then, the rear end would be so low that if the bike was parked on the sidestand it would stand up straght, or perhaps even to the wrong side, as in tip over to the right side....
If the rear drive stayed at close to the same angle as if the bolt was in, then why would the shaft be damaged?

As for the bolt becoming loose: At the factory, most of the screws are torqued by automated machinery, so if the bolt is there, it will be properly torqued.
Even in the unlikely event that the LockTite was missing (The bolts are precoated), unscrewing this bolt, even when the bike is parked on centerstand, takes an effort. For the screw to come loose while it's loaded takes an even higher force. Naahh....

I'm with @Santa-2512 here. We need pictures....

PetesBMW said:

My new 1250 ADV only 6 weeks old, drive shaft splines failed at only 294 Kms is this a common problem

Pete

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PetesBMW said:

Hi guys all joking a side , I’m am not a trol bike was recovered from my house today by bmw , it seems the bolt above the rubber gater holding the whole drive together came out and is gone , they are going to sort it out ,will up load a photo soon for all to see

Thanks

Pete

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Looking objectively at the evidence provided by the OP Pete.. the bike is new, done just under 300 km (not yet had chance to rust the splines together so they would separate easily). The OP states that the paralever bolt WAS completely missing, (thus allowing final drive to pivot open or close under acceleration /deceleration and braking, this is the reason why the paralever bolt is so important..See Jesus Nut below)
Just imagine for a second that you left the paralever bolt out.. and rolled the bike off it's centre stand and onto it's wheels, I think the weight of the bike would try to close the final drive up and try to compress the gaiter flat (because the FD pivot point is on the underside of the swing arm). The gaiter wouldn't collapse up flat because the drive shaft is a fixed length and would tend to support the weight of the bike, so all would appear normal.. no squashed up flat gaiter !
Now put the bike in first gear to set off (not forgetting that first gear multiplies the torque for maximum thrust) but the missing paralever bolt won't stop the final drive drive from opening up. As you accelerate in first gear the final drive pivot could open up and pop the fixed length drive shaft off the front or rear spline (only the rubber gaiter and the friction of the new 'yet unrusted' splines' to stop it doing so), versus the resistance of accelerating a combined motorcycle weight of 250kg + 80kg rider. If either end of the drive shaft splines slid apart then drive would instantly be lost, giving the impression the splines had stripped. In actual fact once separated they can be quite difficult to reassemble especially the front..I know from experience as I've just greased mine. The OP said he was only travelling at approx 18 kph when drive was lost so almost certainly in 1st gear = max thrust = max torque reaction from FD.
I would be very surprised if it's not just a case of no paralever bolt to hold FD together, spline separated, no drive, appears stripped splines. Time will tell,
the paralever bolt shouldn't have come out though as Knut quite rightly states in his post.
The paralever bolt on a BMW water-cooled boxer is probably the motorcycle equivalent of the 'Jesus Nut' on a helicopter that holds the main rotor to the mast. During the 1960's Vietnam War the 'Huey' helicopters lost a few of these nuts and the term became infamous for obvious reasons.

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Is it called a jesus nut because your likely to be meeting him if it comes off mid flight ?

The Ford focus has Jesus clips on it's inner mirror cover.

I worked for a tier one suplier and had to remove this cover regularly,

it was held on with what can only be described as a Jesus clip,

An evil U shaped spring clip with 4 barbs, that bit into the metalwork, and your skin when trying to remove or replace them .

But my initial statement stands

put up or shut up

spoonz said:

Is it called a jesus nut because your likely to be meeting him if it comes off mid flight ?

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Yes I do believe that's the reason why it's called the 'Jesus Nut'.
It is mentioned in the very funny and factual book 'Chickenhawk' by Robert Mason that is an absolutely brilliant read, I couldn't put it down once I started reading it. In fact I may buy it and read again. Recommended reading for COVID-19 lockdown motorcyclists anywhere.
"Am I a hawk, or am I a chicken"?
hope you enjoy it as much as I did if you get a copy.

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Micko123 said:

During the 1960's Vietnam War the 'Huey' helicopters lost a few of these nuts and the term became infamous for obvious reasons.

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Your statement is incorrect. The term refers to the failure of the entire system due to one component (also called single point failure) as mentioned in the Wiki page you reference to. And how many Hueys crashed due to the failure of the bolt? None.

Micko123 said:

Looking objectively at the evidence provided by the OP Pete.. the bike is new, done just under 300 km (not yet had chance to rust the splines together so they would separate easily). The OP states that the paralever bolt WAS completely missing, (thus allowing final drive to pivot open or close under acceleration /deceleration and braking, this is the reason why the paralever bolt is so important..See Jesus Nut below)
Just imagine for a second that you left the paralever bolt out.. and rolled the bike off it's centre stand and onto it's wheels, I think the weight of the bike would try to close the final drive up and try to compress the gaiter flat (because the FD pivot point is on the underside of the swing arm). The gaiter wouldn't collapse up flat because the drive shaft is a fixed length and would tend to support the weight of the bike, so all would appear normal.. no squashed up flat gaiter !
...............

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Soo... In less than one tank of fuel, the bolt, torqued and locked by Locktite, should unscrew it self, disappear during a ride. without the rider noticing it ????

When assembling a bike, robots pick alle the parts to be used for each particular bike, as ordered by customer/dealer. Then the parts are delivered to the assembly line in a parts package, and each part must be fitted. If not all parts are mounted, the unmounted part would be noticed. So, the chances for a vital part not to be mounted stands the chances of a snowball in hell. Let alone the chances of passing the quality control, including a run on the bench prior to delivery.

If the bike (with the alleged missing bolt) was lifted to the center stand, the bevel gear, with the added weight of the wheel, would bring the wheel to the ground, thereby allowing the link arm to pop out of it's position as the bevel gear fell down. And then, when the bike was moved off the center stand, the link arm was just hanging there, keeping it's position in the open air (hinged up front in the other end of the arm) and slide right back in, all this without the rider notice??

I appreciate your positive attitude and willingness to find a plausible explanation, but this is just too good to be true...

Without pictures, this did not happen.....

Warlord said:

Oh I dunno...

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Ok, apart from the 180 bhp 17 inch wheel bla bla bla bla......over and over and over again

PetesBMW said:

Hi guys all joking a side , I’m am not a trol bike was recovered from my house today by bmw , it seems the bolt above the rubber gater holding the whole drive together came out and is gone , they are going to sort it out ,will up load a photo soon for all to see

Thanks

Pete

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The facts as we know them so far...Pete isn't a troll, the bike is recovered from his house by BMW, only Pete and Recovery man there I presume, " it seems the bolt above the rubber gaiter holding the whole drive together came out and is gone" this could only be the paralever bolt (read Jesus Bolt), I don't know why it was gone, Pete doesn't say. The fact that it was gone is a big clue though. This thread is turning out to be a real mystery. I just wish
Athur C Clarke was still alive, he would have cracked it by now.

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Micko123 said:

The facts as we know them so far...Pete isn't a troll, the bike is recovered from his house by BMW, only Pete and Recovery man there I presume, " it seems the bolt above the rubber gaiter holding the whole drive together came out and is gone" this could only be the paralever bolt (read Jesus Bolt), I don't know why it was gone, Pete doesn't say. The fact that it was gone is a big clue though. This thread is turning out to be a real mystery. I just wish
Athur C Clarke was still alive, he would have cracked it by now.

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Puzzles the sh''' out of me too

Somehow, if this is the case, there are probably some missing information that will suddenly make this more sensible

Chains - they’re the future...

Chains belong on bicycles...ridden little girls or gays wearing Spandax...
This is how crazy this forum is..."Shaft failure" and the rubber boot came off...Happened to me once.15 min fix on warranty ! I take a driveshaft over a chain any day.Change the reardrive oil / 180 ml every 6 k miles and the shaft/reardrive will give you 100K miles of reliable service...Yes if you run wash-board off road I would take a chain as the constant shock-load will kill the U-joints.But that is just commons sense a lot of people lack nowadays...