Aerox 50cc L/C losing power

My aerox tends to lose power at start up, traffic lights and junctions it just doesn't want to pull away, and the only way for it to pull away is to hold the manual choke on all the time i am riding it?? any ideas please on what it could be cause even when i hold manual choke it struggles??? Thanks

 

hey mate check your air filter sounds like it isnt getting enough to burn the fuel