It is chain drive.
Belt Drive
the chain should have 1/2 to 3/4 inch free travel in the center of the sprockets
No Harley Sportster has ever had a cam chain. The camshafts are gear driven, directly off the crank. No tension adjustment required.
yes on the bottom of the primary
A 2003 sportster has a chain drive for the promary, firm the engine to the transmission, and a belt drive final drive. The final drive is from the transmission to the rear wheel.
Get the repair manual, follow the steps
dheck tention on drive chain, probable too tight
change tention arm pully bad barings
the temperture increase whenever the tention increase
Take the rotor and the clutch basket off at the same time
tention