F650 Dakar Cush drive lug broken !?!

[Sgt Pepper]

Hi,

I have a high mileage Dakar, at around 64,000 miles, which had a single lug shear off on the cush drive (one of the three that link the rear sprocket carrier to the rear wheel hub/cush drive rubbers). I assumed because of the mileage that it was just straight long-term fatigue. So I bought a perfectly serviceable low mileage one off a fellow GS'er and fitted it. Trotted off to Holland and one of the lugs broke off that one too..about 500 miles later !

The rubbers all look in good condition and there are no obvious/visible faults. Does any body have any suggestions as to what could be the root of the problem please ?

Many Thanks,

Mike

 

[Timolgra]

Hi,

I have a high mileage Dakar, at around 64,000 miles, which had a single lug shear off on the cush drive (one of the three that link the rear sprocket carrier to the rear wheel hub/cush drive rubbers). I assumed because of the mileage that it was just straight long-term fatigue. So I bought a perfectly serviceable low mileage one off a fellow GS'er and fitted it. Trotted off to Holland and one of the lugs broke off that one too..about 500 miles later !

The rubbers all look in good condition and there are no obvious/visible faults. Does any body have any suggestions as to what could be the root of the problem please ?

Many Thanks,

Mike

Any number of reasons, but someone could have put it in a vice to undo the sprocket bolts etc.

 

[Sgt Pepper]

Thanks, however I've owned it since 2004/11,000 miles and this is now the second failed carrier within a few thousand miles....and no vice has been near it !

 

[Dansin]

How worn are the rubbers and how loose is the chain? If there's a significant amount of wear on the rubbers then could extra pressure be put on the lugs as the chain takes up any slack? Just speculating, no knowledge here.

 

[Sgt Pepper]

Thanks Dansin.

I'm at about the same place. The rubbers did look fine when I fitted the last sprocket carrier but me thinks a closer inspection is now called for ! : The chain, whilst appears still to be fine (as doesn't need regular adjusting) has been on for around 16-20,000 miles. (The wonder of a Scottoiler.)

I've sourced another secondhand carrier from a fellow GS'er and I'll have to do a fuller inspection when I get a chance to fit it.

Regards,

Mike

 

[komatias]

How about posting some pictures? You can tell from the fracture what has happened in most cases.

 

[Sgt Pepper]

Mmmm. Thanks for the suggestion. Might try that next week if I get a chance to get the wheel off. The lug is actually breaking right near the base which suggests the whole lug is being hit with too much force for some reason. I'm wondering if there is actually something wrong with the wheel hub itself...perhaps that has fractured. Anyway, I need to get the wheel off again to do some research first..and maybe take some photos ! Thanks again