I'm sorry that was a fat finger typo. The part number is 608384. Yes I've tried Messicks with no luck and a couple other places that do not have used or new. On Messick's diagram the exploded view is number 12. If I knew how to post a picture of the sprocket and of the parts diagram I would LOLAre you sure the part number is #608383? I ask because I tried looking it up on L454 parts diagrams and could not find it. You may want to try Messick's, I had luck getting parts there for my L454. -Stef