You know this is a bad news... a very bad news if its only on 9k ... its Honda and its 9K .... carbon nahi honi chahye ..
get your bike checked first... use HiOctane, and STP Head cylender cleaner in Petrol, and wash your silencer with Caustic Soda to puke all carbon out... if sound comes back you are good also get its Carb and Plug checked may be not all petrol is burning ... these are jsut suggestions I hope nothing big is wrong and only setting are out.. ager still problem persist keray tu then you really have a BAD BAD news...