I'm know the axle blocks are different sizes. My new 09 450 only has 2 hours on it so the chain does not need adjusting yet. The owners manual is not much help ( I liked my hondas owner manual waay better). I looked for a reference point on the swingarm pivot bolt and just measure but I can only do this from the left side as the right side is recessed. So what are you guys doing for keeping the axle straight. Also from the factory I measured my chain slack from the point that it says to and I only have about 1 3/4 inch slack . It is supposed to have 2-2.4 inches and today when I was hitting a little bump there was a pop sound coming from the rear. Could this be from the chain to tight?