Yamaha YZ250 2021 Owner's Manual

TROUBLESHOOTING7-1EAM20148TROUBLESHOOTINGEAM30309GENERAL INFORMATIONTIP• Troubleshooting information provided here does not cover all the trouble symptoms, possible causes,and remedial actions. Some items may not apply depending on the model. Use this information as aguide and quick reference matrix when performing basic troubleshooting. Refer to the each chapterfor detailed information on checking, adjustment, and replacement.• The following guide for troubleshooting represent quick and easy procedures for checking these vitalsystems yourself. However, should your motorcycle require any repair, take it to a Yamaha dealer,whose skilled technicians have the necessary tools, experience, and know-how to service the motor-cycle properly.EAM30612TROUBLESHOOTING OF ENGINEEngine will not start or is difficult to start, but it cranks.Symptom Possible cause ActionsSpark plug does not produce aspark Have a Yamaha dealer check the electrical system.Fuel not suppliedEmpty fuel tank Fill the fuel tank with fuel.Clogged fuel tank cap breatherhole Clean the fuel tank cap.Clogged or damaged fuel hose Clean, repair, or replace the fuelhose.Fuel leakage Check the fuel passage. Repair orreplace as necessary.Clogged fuel cock strainer Clean or replace the fuel cockstrainer.Clogged fuel cock Clean or replace the fuel cock.Cracked, damaged or worn fuelcock Replace the fuel cock.Clogged carburetor fuel passage Clean the carburetor.Clogged needle valve or needlevalve seatClean the needle valve or needlevalve seat.Damaged float Replace the float.Clogged pilot jet Clean the pilot jet.Clogged starter jet Clean the starter jet.Bent or damaged starter plunger Replace the starter plunger.Incorrectly adjusted starter cable Adjust the starter cable.— Water or foreign material in fuel,degraded fuel Change fuel.