Yamaha YZ250FM 2021 Owner's Service Manual

ENGINE3-11EAM30412CHECKING THE ENGINE IDLING SPEEDTIP• Because the air pressure is lower at high alti-tudes, the air-fuel mixture will become richer. Ifthe idling speed is low, turn the idle screwclockwise to increase the speed before the ad-justment.• Before adjusting the engine idling speed, makesure that the air filter element is not clogged,the engine compression is proper, and thethrottle grip free play is proper.• Adjust the engine idling speed with the starterknob pulled in completely.1. Start the engine, and warm this up until the oilhas reached the specified temperature.2. Measure the coolant temperature using theYamaha diagnostic tool.3. Install:• Digital tachometerTIPGet the high tension cord “1” of the ignition coilpinched in the detector “a” of the digital tachom-eter.4. Measure:• Engine idling speedOut of specification  Regulate.5. Adjust:• Engine idling speeda. Turn the idle screw “1” to make an adjust-ment.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.Yamaha diagnostic tool USB (US)90890-03269Yamaha diagnostic tool (A/I)90890-03264FI diagnostic tool sub–lead90890-03212FI diagnostic tool sub–leadYU-03212OBD/ GST Leadwire kit90890-03249Coolant temperature70–80 C (158–176 F)Digital tachometer90890-06760Digital tachometerYU-39951-BEngine idling speed1900–2100 r/minThrottle grip free play3.0–6.0 mm (0.12–0.24 in)1aaa1111