I came up with a good way to see how much slop you need in your chain. I have an 87 250X (same as a 300EX). First, I loosened the chain as loose as I could Then I took a ratchet strap and wraped it around the frame near the rear grab bar and kind of both sides of the axle so I was pulling evenly on the axle. Then I sat on the rear while tightening the strap. I tightened it as far as it would go, almost totally compressing the shock. Then I tightened the chain until just snug. Then I undid the strap and measured the slop. Well, after all that work, it was EXACTLY what the manual said it should be. lol. Sheesh. I guess you should trust the manual. But hey, it was fun.