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10.2 - Trouble Shooting - Poor Performance at Idle and Low Speed

  1. Intake Manifold Inspection – Check the intake manifold seals for leaks.

Is there a leak in the manifold?

NO      -  Go to STEP 2

     YES     -  Loose carburetor mounting bolt (nuts)

  • Damaged, cracked insulator/spacer
  • Damaged intake manifold gasket
  • Damaged O-ring seal
  • Cracked or broken intake manifold (pipe)


  1. Spark Test – Test for ignition spark by removing the spark plug and using a spark tester found at your local auto shop or by inserting it into the spark plug cap. Place the open end of the spark plug on a metal part of the engine and kick start the engine or use the electric start. You should see a nice blue spark on the end of the spark plug. A faint spark will not start the engine.

Is there a good spark?

NO  - Fouled or faulty spark plug

  • Broken or shorted spark plug wire or spark plug cap.
  • Broken or shorted ignition coil
  • Faulty ignition CDI box
  • Faulty or shorted magneto assembly
  • Broken or shorted engine stop switch
  • Loose or corroded wires and/or connectors (always clean bad electrical connections)

YES  - Go to STEP 3


  1. Carburetor Air/Fuel Mixture Screw Inspection – Check the carburetor air/fuel mixture screw. Turn the screw clockwise until you feel it stop. DO NOT TIGHTEN> Back out the screw counter-clockwise 1.5 full turns.

Is the screw setting correct?

NO      -  Adjust using the above procedure or see your local AJ1 dealer

     YES     -  Go to STEP 4


  1. Ignition Timing Inspection – See your local AJ1 dealer or local motorcycle repair shop to have the ignition timing inspected. Only attempt these procedures if you are qualified and have the proper tools required.

Is the ignition timing normal? (Timing is not adjustable)

NO      -  Faulty CDI ignition box

  • Faulty ignition pulse generator

     YES     -  See your local AJ1 dealer to have your motorcycle serviced.

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