So I converted my 08 690 Enduro to supermoto recently and I was worried about natural chain rub from fitment of a 160 wide rear. For assurance I fitted an upper chain guide from an 06 690 SMC.
When I fitted and tried it the first time, it rubbed like mad. The poly block took a hell of a beating after the first two rides, so I decided to get it re-machined. Now it fits like a glove.