The carb isn't hard to pull apart, just take the bowl of and pop the pin out of the float, uder that youll see the brass jets, just unscrew them and blow them out with compressed air, them spray a bit of carb cleaner in all the holes of the carb and blow it out, make sure you havnt got any loose bits before you blow it out or youll loose them
Follow this link it has everything you need to know
CVK40
Hope this helps