It happens that in earlier models the rocker arms can fail causing devastation in the engine. Manufacturing defect, material, construction? There are many theories. It is not that bad if bearing collapses on a rocker and the owner quickly catches the strange noise from the engine. Worse if the arm cracks spreading broken bits further in the engine. Rebuild guaranteed.
KTM has released a new, redesigned model of rocker arms. And supposedly the improved version no longer causes such problems. Unfortunately, KTM does not identify this as a design fault. It does not require immediate reaction and does not call users to come to get it replaced at the manufacturer’s cost. So if you want to have a good night’s sleep, then pay and cry.
Our KTMs built in 2012 may have unlucky units. Not wanting to check what it is like to be within a group of “lucky people”, one of the first things I did was pulling the engine cover off and replacing them. Relatively simple operation but requiring precision. After replacement, I checked valve clearance, as a gap between the arm base and the adjusting plate has a possibility of changing.
To replace rockers, it is good to have a repair manual with all necessary information, a good torque wrench and possibly correct thickness of shim plates. I always write all the services I have done in our vehicles, so all details ended up saved in the appropriate file. Next time I will know if any change has appeared since the last service. This simple habit may help to catch the oncoming problem.
I keep the old rocker arms for a rainy day, in case something goes wrong.