Maybe I was unlucky but I am more inclined to think that there is an inherent weakness in the design. I have even modeled the cover in 3D CAD and run FEA stress analysis to highlight the areas of weakness. That has lead me on to manufacture a repair part, as I have a spare casing now!!

I don't think that this is particularly common but I did find a couple of references on the badweatherbikers site.

My opinion is that careful adjustment of the clutch, to the manual, would minimise the chances of this from happening.

There is a solution on Badweb whereby the guy faced off the back of the recess inside the cover and screwed a steel plate on. Better SN curves as you know...

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08 Specialized Langster

Rumours say, the old 2003 black primary covers had been more solid (and they look a bit different), but before you are going to swap your's, check the shifter shaft diameter. There are two different.

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"It is often said that before you die your life passes before your eyes. It is in fact true. It's called living."
Terry Pratchett