Had a pair of oem '06+ YZF bar mounts, and a nice original oem YZF fat bar off my old '07 YZ450, and that 450 is long gone, but still had the 1-1/8" setup , and thought i wonder if the mounts would work in the K5 , so long story short the answer is yes. Both styles of bolt are 12mm. The only issue with running the YZF mounts is the fact the studded portion of the mount does not have a "shoulder" like the oem K5 mounts. With the K5, you crank down the nut until it bottoms out on the shoulder. The YZF's you will need to sufficiently preload the nut until you feel your desired level of "stiffness" YZF's don't use the rubber tapered cones as compared to the K5 setup. After piloting a newer YZ with high/foreward type bars, transitioning to a stock K5 is like dragging your knuckles on the ground from low bars ! I even took it a step further and added a 1-1/8" bar riser. Cable clearence is also sufficient.
