But in your case, "normal" really isn't that good. Yamaha used several different tensioner assemblies over the years. All had a locknut to lock the adjustment in place before fitting the cover nut except your type D assembly. On yours, the acorn cover nut was meant to act as the locknut. But, as you tighten it down, there's no way to stop it from possibly tightening your adjuster more. Yamaha realized the error in their ways and came out with the revised type E assembly, putting the locknut back on there. The best thing you can do is update yours to this later type E. Details are here, post #22 .....
http://www.xs650.com/threads/cam-chain-tensioners.1056/page-2[/QUOTEWha