Yamaha YZ250X 2022 Owner's Service Manual

ENGINE3-5EAM20135ENGINEEAM30607ADJUSTING THE PILOT AIR SCREW1. Adjust:• Pilot air screw “1”TIPTo optimize the fuel flow at a smaller throttleopening, each vehicle’s pilot air screw has beenindividually set at the factory. Before adjustingthe pilot air screw, turn it in fully and count thenumber of turns. Record this number as the fac-tory-set number of turns out.a. Turn in the pilot air screw until it is lightlyseated.b. Turn out the pilot air screw to the factory-set number of turns.EAM30412CHECKING THE ENGINE IDLING SPEED1. Start the engine and thoroughly warm it up.2. Adjust:• Engine idling speeda. Turn the throttle stop screw “1” until theengine runs at the lowest possible speed.EAM30475CHECKING THE THROTTLE GRIPTIPPrior to adjusting throttle grip free play, the en-gine idling speed should be adjusted.1. Check:• Throttle grip free play “a”Out of specification  Regulate.2. Adjust:• Throttle grip free playa. Slide the adjuster cover.b. Loosen the locknut “1”.c. Turn the adjuster “2” until the specifiedfree play is obtained.d. Tighten the locknut.WARNINGEWA18470After adjusting the throttle grip free play,start the engine and turn the handlebar to theright and to the left to ensure that this doesnot cause the engine idling speed to change.EAM30254CHECKING THE SPARK PLUG1. Disconnect:• Spark plug cap2. Remove:• Spark plugNOTICEECA13330Before removing the spark plug, blow awayany dirt accumulated in the spark plug wellwith compressed air to prevent it from fallingAir screw turns out1-1/4Throttle grip free play3.0–5.0 mm (0.12–0.20 in)aG088895