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My sprocket retainer has worn out without me noticing. Chain has pulled sprocket toward engine casing and ground away the swing arm. Carnage. Never seen this before, and I'll not let it happen again! Now I have a f*cked swing arm and damage to my Renthal sprockets and chain. All for the sake of a £5 clip.
 

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Oops. This should not even happen without the sprocket retainer. Are you sure that your chain wheels were exactly aligned? Now they are.
 

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Miles on the original clip: 28K

Before touching: Clip is to the inside of the groove.

Definitely looks like a wear item that should be replaced. I'm going to change with every sprocket/chain; 15-20K.

There was wear on both sides of the teeth, but the great majority to the inside.

With perfect alignment and perfect chain tension, etc, the sprocket might ride in one spot. Real world: it moves and tends to one side or the other and the clip will wear.


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Could this be avoided if the chain was lubricated properly at appropriate intervals? Perhaps lubricating the retainer also? The picture looks like that sprocket cover was never removed?
 

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Sprocket cover has been off three times: 1) 12k mi new chain and sprocket 2) 28K mi new chain and sprocket 3) 28k new retainer clip. Both chains had quite a bit of life left, but upcoming long trips and I don't like limping home with a wonky chain. Chain lubed typically around 400mi, so I don't that made much difference to the clip.

The manual doesn't say lube the shaft splines or the clip and I don't think there was any lube from the factory. It couldn't hurt, but I don't think it would help much. I'm putting a new clip on and am not worrying about it.
 

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It looks to me like poor quality steel and/or poor heat treatment. The way the teeth have mashed shows that the metal is very soft and unsuitable for this application.

Suggest a little earner for someone, laser cut retainers out of a better grade of steel and sell to Scrambler owners!
 

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The front sprocket is designed to float freely along the splines during fitment. Fit the chain and get the alignment of the chain along the swing arm correct before you torque up the two bolts on the front sprocket retaining clip.

The angle of the bolt holes for fitment of front sprocket retaining clip, once bolted in place, grips the splines and locks the front sprocket on the splines to make it impossible for the front sprocket to float along the splines once the clip retaining bolts are coated in threadlock and torqued up to 6Nm.

The possible fatigue type wear in the photograph on this retaining clip is such that the front sprocket retaining clip no longer locks the front sprocket and the front sprocket has been able to move freely along the splines. A lesson for us all and I am sad for the damage to your bike.

When you change the chain, also consider replacing the replaceable chain runner guide on the swing arm, on some manufacturers bikes there is one on the underside of the swing arm near the front sprocket too.
 

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It looks to me like poor quality steel and/or poor heat treatment. The way the teeth have mashed shows that the metal is very soft and unsuitable for this application.

Suggest a little earner for someone, laser cut retainers out of a better grade of steel and sell to Scrambler owners!
Much rather replace the sacrificial retainer now and then than have a hardened steel cheap consumable chew it's way through the splines of the shaft.
 

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...

The angle of the bolt holes for fitment of front sprocket retaining clip, once bolted in place, grips the splines and locks the front sprocket on the splines to make it impossible for the front sprocket to float along the splines once the clip retaining bolts are coated in threadlock and torqued up to 6Nm.

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Sorry, but this is wrong. Also on a new bike the sprocket will float free between the splines. That's per design.
 

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That said, if the rear wheel is out of alignment the front sprocket can put a side load on the retainer making it wear prematurely...
 

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Much rather replace the sacrificial retainer now and then than have a hardened steel cheap consumable chew it's way through the splines of the shaft.
Yes. The retainer by design has softer steel no doubt.
Perhaps it could have a bit stronger alloy and still not grind away the shaft? That is the question.

Ducati engineers are being tasked to improve the design in future bikes I'm guessing.
 

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Yes. The retainer by design has softer steel no doubt.
Perhaps it could have a bit stronger alloy and still not grind away the shaft? That is the question.

Ducati engineers are being tasked to improve the design in future bikes I'm guessing.
It's considered a consumable part, like the chain/sprockets. At the risk of possible wear to the counter shaft splines, it seems sensible to just replace the retainer clip whenever you change the chain/sprockets. They are pretty cheap.

I think I'll double check the chain guide on the swingarm too. I've never considered replacing that but seems wise. Also need to get something to help me check wheel/chain alignment more accurately than relying on the adjuster marks. Seems wear on the retainer is much reduced by doing both of these.
 
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