Scooter running problems, help?

Hi there guys wondering if anyone can help me, i come to start my scooter and i have to give it some revs to get it going as it wont start without it, then once running it will just cut out. if i ride the scooter for a few minutes, then sometimes it will happily idle, other times it wont as all, also ive noticed the exhaust is quite sutty black deposits at the end of it, the scoot is a 4 stroke, just wondering if anyone can help me, many thanks.

 

what bike is it? have you checked the carb and air filter are clean?

 

its a generic XOR 125, the filter is perfectly clean as i checked and also the carb is clean :/