Yamaha WR250F 2008 Owner's And Service Manual page 205

SPARK GAP TEST
1. Disconnect the ignition coil from
spark plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark tester
"1" (ignition checker "2") as
shown.
• Ignition coil "3"
• Spark plug "4"
A. For USA and CDN
B. Except for USA and CDN
4. Kick the kickstarter crank.
5. Check the ignition spark gap.
6. Start engine, and increase spark
gap until misfire occurs. (for USA
and CDN only)
Minimum spark gap:
6.0 mm (0.24 in)
CHECKING THE COUPLERS,
LEADS AND IGNITION COIL
CONNECTION
1. Check:
• Couplers and leads connection
Rust/dust/looseness/short-circuit
→ Repair or replace.
• Ignition coil and spark plug as
they are fitted
Push in the ignition coil until it
closely contacts the spark plug
hole in the cylinder head cover.
CHECKING THE ENGINE STOP
SWITCH
1. Inspect:
• Engine stop switch conduction
Tester (+) lead → Black lead "1"
Tester (-) lead → Black lead "2"
Result
Conductive (while the
engine stop switch is
pushed)
Not conductive while it is pushed →
Replace.
Conductive while it is freed → Re-
place.
Set the tester selection position to "Ω
× 1".
2. Inspect:
• Rubber part "a"
Tears/damage → Replace.
CHECKING THE MAIN SWITCH
1. Inspect:
• Main switch conduction
Tester (+) lead → Red lead "1"
Tester (-) lead → Brown lead "2"
Result
Conductive (while the
main switch is moved
to "ON")
Not conductive while the main switch
is moved to "ON" → Replace.
Conductive while the main switch is
moved to "OFF" → Replace.
Set the tester selection position to
"Ω×1".
7-4
IGNITION SYSTEM
2. Inspect:
• Main switch indicator light
Use 12 V battery.
Battery (+) lead → Red/Black lead
"1"
Battery (-) lead → Black lead "2"
Indicator light does not come on →
Replace.
3. Inspect:
• Rubber part "a"
Tears/damage → Replace.
CHECKING THE IGNITION COIL
1. Remove the ignition coil cap.
2. Inspect:
• Primary coil resistance
Out of specification → Replace.
Tester (+) lead → Orange lead "1"
Tester (-) lead → Black lead "2"
Primary Tester se-
coil resis- lector posi-
tance
0.08–0.10
Ω at 20 °C
(68 °F)
3. Inspect:
• Secondary coil resistance
Out of specification → Replace.
Tester (+) lead → Orange lead "1"
Tester (-) lead → Spark plug termi-
nal "2"
tion
Ω × 1