Basically, in 1st gear when I hit roughly 6000 rpm the [size=100%][/size][size=inherit]engine[/size][size=100%][/size]/exhaust starts making a 'duel noise'  - the engine sounds like it's starting to strain. Then at 10000 rpm the bike loses [size=100%][/color][/size][size=inherit]power[/size][size=100%][/size] and actually starts to slow down!! It feels like a massive dip in power. Anyone any ideas please?
 
 Ta