2003 Kawasaki KLF250 Service Manual., Page 304Get this manual
17-12 APPENDIX Troubleshooting Guide
Fuelair mixture incorrect: Pilot screw andor idle adjusting screw maladjusted Pilot jet, or air passage clogged Air cleaner clogged, poorly sealed, or missing Starter jet clogged No spark; spark weak: Spark plug dirty, broken, or maladjusted Spark plug cap or spark plug lead trouble Spark plug cap not in good contact Spark plug incorrect Crankshaft Sensor trouble Igniter trouble Ignition coil trouble Battery voltage low Ignition or engine stop switch shorted Wiring shorted or open Fuse blown Compression Low: Spark plug loose Cylinder head not sufficiently tightened down No valve clearance Cylinder, piston worn Piston ring bad (worn, weak, broken, or sticking) Piston ringgroove clearance excessive Cylinder head gasket damaged Cylinder head warped Valve spring broken or weak Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface) Compression release mechanism trouble Poor Running at Low Speed: Spark weak: Spark plug dirty, broken, or maladjusted Spark plug cap or spark plug lead trouble Spark plug cap shorted or not in good contact Spark plug incorrect Igniter trouble Crankshaft Sensor trouble Ignition coil trouble Battery voltage low