If it is backfiring the timing is set incorrectly or the spark plug wires are not connected in the correct order.
The best answer for this is: Get a tune-up.
Change the abs motor.
To stop a Yamaha 1300 from backfiring, first ensure that the air-fuel mixture is balanced, as a lean mixture can cause backfiring. Check and adjust the carburetor or fuel injection settings, if applicable. Additionally, inspect the exhaust system for leaks and ensure that the spark plugs are clean and functioning properly. Regular maintenance and tuning can also help prevent backfiring issues.
Disconnect battery.
many things. did you check the electrical connections and fuse to the blower?
Rev the engine six or seven times before coming to a complete stop. Rev it all the way to the edge every time you stop.
try replacing the idol air control motor.
check and or clean air idle speed motor
well if its a 2 stroke it needs new reeds if not, your timing is prolly off a bit
bad parking relay in motor
Double-Stop - 1968 was released on: USA: May 1968
More than likely you have a exhaust leak.Check the headpipe seal