1. GENERAL INFORMATION ZING125 POOR PERFORMANCE (AT HIGH SPEED) Inspection/Adjustment Symptom Probable Cause Check ignition timing Correct Incorrect Faulty CDI unit Faulty pulser coil Check valve clearance Correct Improperly adjusted valve clearance Incorrect Worn valve seat Check fuel filter for fuel supply Fuel flows freely Empty fuel tank Fuel flow restricted Clogged fuel filter Clogged fuel tank cap breather hole Check carburetor for clogged jets Not clogged Clogged Clean and unclog Check valve timing Correct Incorrect Cam timing gear aligning marks not aligned Check valve spring tension Not weakened Weak spring Faulty spring 1-18