The chain tensioner blocks on all models of KTM tend to crack at some time, and that meant replacing the axle, as you could not get the threaded block on the fixed side. The OEM part consists of a full rear axle, yet it is only necessary to replace the fixed block, by unscrewing it from the axle.

Sold as a pair, these chain tensioner blocks will replace your old cracked ones at a fraction of the cost.