03 predator500 problem's

[iceman_jdm]

ok y'all i need some help....i bought an 03 predator500 off one of my friends about 6 months ago... when i picked it up it ran fine and i was very pleased with it....two weeks after i bought it..it stoped runing right the motor makes a knocking noice...the carb is always leaking fule and it isent keeping a charge on the battery...i am getting seriously fed up with it beacuse i have no clue what to do ...if anyone can help it would be awsome

thanks.