Yamaha yz250 2015 User Manual

6-2
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap test Spark → *Clean or replace spark plug.
No spark ↓
Check entire ignition system for connection. No good → Repair or replace.
OK ↓
Check engine stop switch. No good → Replace.
OK ↓
Check ignition coil. (primary coil and secondary
coil)
No good →
Replace.
OK ↓
Check spark plug cap. No good → Replace.
OK ↓
Check CDI magneto. (pickup coil and charging
coil)
No good →
Replace.
OK ↓
Check neutral switch. No good → Repair or replace.
OK ↓
Replace CDI unit.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-03112-C/90890-03112
6

Yamaha yz250 2015 Specifications

General

Displacement	249cc
Bore x Stroke	66.4mm x 72.0mm
Compression Ratio	8.9~10.6:1
Ignition	CDI
Transmission	5-speed; multiplate wet clutch
Final Drive	Chain
Front Tire	80/100-21
Rear Tire	110/90-19
Wheelbase	58.3 in
Seat Height	39.1 in
Ground Clearance	14.2 in
Fuel Capacity	2.1 gal
Wet Weight	227 lbs
Engine Type	2-stroke
Fuel System	Keihin PWK38S
Front Suspension	KYB Speed-Sensitive System inverted fork; fully adjustable
Rear Suspension	12.4-in travel
Front Brake	Single disc, 250mm
Rear Brake	Hydraulic single disc brake, 245mm
Width	32.5 inches