Yamaha WR250F Starting Drill

H. Marc Lewis, 2-April-2001

[These are the supplemental instructions for starting Yamaha YZ/WR 250, 400 and 426 4-stroke singles.]

The decompression lever should be used only while rotating the engine just past top-dead-center on the compression stroke. Do not use the compression release during actual kick starting.

Starting a cold engine

  1. Shift the transmission into neutral.

  2. Turn the fuel petcock to "ON" (or "RES") and fully open (i.e. pull out) the black starter knob (choke).

  3. Leave the throttle closed for starting. In temperatures below 41 degrees F. (5 degrees C.) only, first twist the throttle three or four times to pump some fuel into the intake tract; then close the throttle for starting.

  4. Slowly depress the kick start lever until you begin to feel resistance. Continue depressing the kick lever slowly until there is maximum resistance, which indicates the piston is at TDC (top-dead-center) on the compression stroke.

  5. Pull the decompression lever to the handlebar and hold it.

  6. Slowly depress the kickstart lever about 1.5 to 2" (40-50mm) more. This puts the piston just slightly past top-dead-center.

  7. Release the decompression lever, then allow the kick starter to return to the uppermost position.

  8. With the throttle completely closed and the decompression lever released, start the engine by kicking the kick starter forcefully with a firm stroke.

    Do not open the throttle while kicking the kick starter.
    Otherwise, the kick starter my kick back.

  9. Run the engine at idle or slightly higher until it warms up; this usually takes about one or two minutes. Do not warm up the engine for extended periods.

  10. The engine is warmed up when it responds normally to throttle with the starter knob (choke) turned off (pushed in).


Starting a hot engine

  1. Shift the transmission into neutral if you can. Starting in gear with the clutch adds drag and makes it harder to kick the engine over.

  2. Turn the fuel petcock to "ON" (or "RES") and fully open (i.e. pull out) the red "hot start" knob. Do not use the starter knob (choke)!.

  3. Leave the throttle closed for starting.

  4. Slowly depress the kick start lever until you begin to feel resistance. Continue depressing the kick lever slowly until there is maximum resistance, which indicates the piston is at TDC (top-dead-center) on the compression stroke.

  5. Pull the decompression lever to the handlebar and hold it.

  6. Slowly depress the kickstart lever about 1.5 to 2" (40-50mm) more. This puts the piston just slightly past top-dead-center.

  7. Release the decompression lever, then allow the kick starter to return to the uppermost position.

  8. With the throttle completely closed and the decompression lever released, start the engine by kicking the kick starter forcefully with a firm stroke. If it doesn't start, repeat this step until it does. It will start, don't dispair (unless you're out of fuel)...

    Do not open the throttle while kicking the kick starter.
    Otherwise, the kick starter my kick back.