Over time, gasoline in the carburetor float bowl will evaporate and leave deposits that can clog jets and small passages. Below is a cutaway diagram of the stock CV carburetor found on dual sport models:
Carefully disassemble and clean the carburetor. All ports and orifices can be cleaned by running a copper wire through every orifice/passage followed by a blast of quality carburetor cleaner spray. Be certain carburetor cleaner is sprayed through each and every orifice until it exits another orifice. Blowing out any remaining cleaner or debris with compressed air is highly recommended.
The idle circuit from points 8 through 10 is most often clogged and is critical to easy starting and smooth idle. The starting enrichment (choke) circuit can be cleaned by removing the enrichment plunger and spraying carburetor cleaner through the opening. The spray should exit the enrichment source within the float bowl.
Berrymans B-12 is among the most effective carburetor cleaning sprays available. It can be found at most auto parts suppliers in the USA and Canada. Be sure to wear eye protection as the exit spray may come in contact with your face depending on which way you are holding the carburetor. Rubber O-rings and seals should not come in contact with most carburetor cleaners as this will cause deformation and possible damage. The pilot jet opening is quite small and easily distorted or damaged. Exercise care if a wire is used to clean the opening.