Just purchased a CB1000 ´The Big One´ and it rides perfectly up to 80mph (4200rpm)but hesitates from 6000rpm and upwards. The bike surges, whilst my brothers Cb1000 storms off. I´ve done all normal routine maintenance such like oil/oil-filter, carb balance, air filter and chain and sprocket set. All genuine honda parts. The bike has fairly low mileage of 12000. Starts first time and even revs up and past 6000rpm in neutral gear. Just recently you can hear a slight top end noise but am not sure whether its tap-it or cam-chain. The engine doesn´t look like it has had much work and the whole bike in great overall condition. Any help before i give it away to my brother for spares?