Like andy says, from perfect to unrideable in one throttle twist is wrong. My money is on it being wrong torque on the back wheel axle nut, giving a tiny position slip after working loose. Done 2 track days plus the 3k miles never had any issues. No rust either, cleaned and waxed every 500 miles as per the manual.
interested to know what the problem really is.
Thought that might of been the case but it was pretty tight when i tried to loosen the wheel nut to make adjustments on the side of the road, also the adjusting bolts were both as should be, which should also prevent the wheel being pulled forward. i guess it will hard to know for sure unless i have the chain checked out by the dealer? Did seem fine again once i adjusted it on side of road and have Just ordered set of LighTech Chain adjusters so if have any more issues at least ill be able to adjust much easier.