Here's the skinny
"New Dual-Pivot Camchain Tensioner
At the howling top revs that the new CBR600RR's engine was designed to reach, concerns about precise cam timing and reliability come sharply into play. One main component that plays a crucial role in the CBR's valve drivetrain operation is its cam chain. At revs approaching 15,000rpm, not to mention the violent thrashes of acceleration and deceleration a motorcycle is exposed to over the course of a road race, the camchain comes in for especially hard punishment. Conventional spring-loaded camchain tensioners simply aren't up to job of maintaining steady pressure and tension on the chain under these conditions, so the CBR600RR's engine designers countered this potential problem with a simple yet ingeniously effective dual-pivot tensioner system.
Featuring a new two-piece configuration, the long standard camchain guide that extends upward from just above the crankshaft gear is now held by a short overlapping secondary guide that gives the tensioner preload spring much greater leverage to hold the chain steady under racing's violent stresses, and maintain precise valve timing throughout the new engine's ultra-wide power band."