Having ridden just 1500km on my new bike, (fantastic but...) I am experiencing major power loss at 5600rpm, most noticable in 4th and 5th gear. It feels as if a cylinder has dropped and to rectify, I have to close the throttle and reopen it once or twice. This condition always occurs at 5600rpm, has anyone experienced a similar problem and can suggest a cure? My dealer as yet has been unable to rectify.