[MCPhotographer]

Originally Posted by greg737

From what I've read here and on the other forum it seems that cam chain wear (and resulting stretch) is highly variable from one bike to another. But it definitely happens.

Also, when the cam chain wears and stretches it does it in spots along its length rather than uniformly throughout the entire chain (this is confirmed by a few forum members who've measured their worn chains). This causes it to go tight-loose-tight-loose as it goes around the drive gear and the camshaft gears. The tight-loose-tight-loose situation causes it to "lash" at the cam chain tensioner, making a knocking noise.

It's not surprising that the cam chain tensioner doesn't stand up well to this abuse. The cam chain tensioner was designed to maintain proper tension on the cam chain in response to engine accelerations and decelerations, which happen (relatively) smoothly and slowly compared to the high-frequency of the tight-loose-tight-loose lashing effect of a partially worn and stretched cam chain.

Bottom line: I believe the engine problems people regularly attribute to the cam chain tensioner are actually related to or entirely caused by an irregularly worn and (as a result of that wear) stretched cam chain. So replacing the cam chain tensioner without dealing with (i.e. replacing) the worn cam chain is pointless.