hey everyone just bought my first 1988 crb 600 the bike starts and runs no problem but if i try to take the rpm to 4000 the engine hesitates backs off the rpm down to 2000 then kicks up to 7000 rpm. the airbox is sealed correctly. the only other thing i can think of is maybe the filter being too dirty. other than that any ideas? thanks

 

Clogged Carbs. Clean them.

 

thanks i'll try that but never clean the carbs on a bike before how is it done?