I removed my engine for some work including checking head flatness, installing titanium valve spring retainers, and possibly splitting the cases to renew sealant on coolant channels.
My first discovery was that my cam chain tensioner had completely failed. The spring had broken and the cap that pushes on the chain guide was dislocated.
In the attached photo, you can see the excessive slack in the chain. Who knows how long it was running like this. It is a track bike, so it runs hard. I vaguely recall noticing a change in off-throttle behavior; I guess that may have been due to valve timing changes. Fortunately, the chain did not jump a tooth - valve timing is still correct. I don't expect to find any evidence of valve-piston collision when I pull the head off... fingers crossed.
I've ordered a manual tensioner. While I've read here about the stock tensioner not working well, I do not recall reading of any failures such as mine. Having now disassembled and examined the tensioner's parts, I can see that the spring is made of poor quality metal that broke from fatigue.
I think this may be something for others to consider fixing before it breaks; not everyone may be as lucky as I was not to have any damage.
Oh, and I am very glad that I bought the KTM engine removal jig (pictured). It made the removal super smooth, and it also enables me to mount the engine in a vise while I work on it. (The vise has a turntable base.)
My first discovery was that my cam chain tensioner had completely failed. The spring had broken and the cap that pushes on the chain guide was dislocated.
In the attached photo, you can see the excessive slack in the chain. Who knows how long it was running like this. It is a track bike, so it runs hard. I vaguely recall noticing a change in off-throttle behavior; I guess that may have been due to valve timing changes. Fortunately, the chain did not jump a tooth - valve timing is still correct. I don't expect to find any evidence of valve-piston collision when I pull the head off... fingers crossed.
I've ordered a manual tensioner. While I've read here about the stock tensioner not working well, I do not recall reading of any failures such as mine. Having now disassembled and examined the tensioner's parts, I can see that the spring is made of poor quality metal that broke from fatigue.
I think this may be something for others to consider fixing before it breaks; not everyone may be as lucky as I was not to have any damage.
Oh, and I am very glad that I bought the KTM engine removal jig (pictured). It made the removal super smooth, and it also enables me to mount the engine in a vise while I work on it. (The vise has a turntable base.)