I have been riding very infrequently over the past couple of years and yesterday was first time out this year. The bike overall ran fantastic but it occasionally made a noise that makes me nervous. I know noises are hard to explain but here goes: whenever I hit it hard in the taller gears and rev'd it out momentarily, as I dropped off WOT I would get a split second chattering noise, it makes me think of a dry bearing noise, and seemed to come from the top end but at 50+ mph on a rocky logging road that's hard to be sure of. I put on 80 miles in the mountains yesterday and otherwise it ran great and the noise never got better or worse during the outing. I recalled hearing the same noise during some previous rides as well. I've owned the bike for 6 years and bought it from a older dual sport type rider who seemed to be very fussy and thorough so I'd say the bike has had a pretty easy life and is now at 6700km/4000 miles of mostly mountain road and trail riding. As an older guy it has plenty of power for me so I don't need to bag on the motor to make it go fast enough. However I like to crank it on an uphill section, roost off the odd corner or loft the wheel over a creek or waterbar so that is usually when my short duration WOT happens. Everything external is tight so its not vibration as far as I'm concerned. I have an aluminum skid plate underneath so I am accustomed to the overall noisy engine sound bouncing back up at me, but this is different and pretty noticeable so this sporadic noise has me a bit worried. If anyone could shed some light or offer suggestions for me it would appreciated.