1999-2004 Yamaha Big Bear 250 Engine Won’t Start

1999-2004 Yamaha Big Bear 250 Engine Won’t Start

1999-2004 Yamaha Big Bear 250 ATV engine won’t start refers to when the motor’s crankshaft either turns but fails to start the engine or the crankshaft doesn’t turn at all. This article details the main reasons why a Yamaha Big Bear 250 will not start and what should be check to resolve the problem.


Fuel System

Check for one or more possible malfunctions:

amaha Big Bear Won't Start 1999 2000 2001 2002 2003 2004

  • Empty fuel tank.
  • Obstructed fuel hose.
  • Dirty fuel filter.
  • Contaminated or deteriorated gasoline.
  • Obstructed fuel strainer.
  • Obstructed Fuel breather hose.
  • Blocked pilot jet.
  • Clogged air filter element.
  • Obstructed pilot air passage.
  • Defective starter plunger.
  • Obstructed starter jet.
  • Damaged or deformed float.
  • Improperly set pilot jet.
  • Damage or worn needle valve
  • Valve seat not seating properly.
  • Fuel level misadjusted.

Electrical System

Check for one or more possible malfunctions:

  • Damaged or incorrect spark plug gap.
  • Worn spark plug electrodes.
  • Incorrect spark plug heat range.
  • Wire between terminals broken.
  • Spark plug cap defective.
  • Ignition coil damaged or shorted secondary/primary.
  • Ignition coil body broken.
  • Defective spark plug lead.
  • Defective CDI unit.
  • Broken woodruff key.
  • Defective pickup coil.
  • Faulty source coil.
  • Defective starter clutch.
  • Defective main switch.
  • Defective starter motor.
  • Wiring shorted, frayed, disconnected or broken.
  • Defective starter relay.
  • Defective neutral switch.
  • Rear brake lever switch defective.
  • Defective stater circuit cut-off relay.
  • Defective start switch.
  • Low compression, damaged piston ring, blown head gasket, etc.

If you plan to service or repair the Yamaha Big Bear 250 (YFM250) yourself, it’s highly recommended to download the online factory service manual from this website before you begin any repair work. It provides detailed step-by-step procedures on how to fix everything listed here. It also contains diagrams, photographs and illustrations to ensure you complete the repair job successfully.

Go to https://www.911manual.com/yamaha-big-bear-350-repair-manual/ to download a repair manual instantly. 


    • Yes, it also pertains to the following models: 1999 2000 2001 2002 2003 2004 YFM 250 X, YFM250XM, YFM250BT, YFM25BV, YFM250XS (BearTracker), YFM250XP, YFM250BW, YFM250XN, YFM250XL

  1. My 2001 Big Bear 250 won’t button start. After riding it for an hour I shut it off for about 5 minutes. Then when I tried to restart it the red oil light came on. Any ideas?

    • Check for a bad switch or contact. Check the wiring up to the start button for breaks or loose connections. Or maybe there is dirt in starter button. Check for corrosion on the negative battery terminal.

  2. My 2002 Big Bear won’t start in cold weather. The temperature outside was 20 degrees and when I went to start the four-wheeler, it wouldn’t start. It would just click like the batter was dead. I was able to get it pull started though. It will start when the temperature outside gets warm.

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