2008-2010 Kawasaki KFX450R Factory Service Manual, Page 88Get this manual
FUEL SYSTEM (DFI) 3-31 DFI System Troubleshooting Guide
Symptoms or Possible Causes 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 bentworn or carbon accumulating on the seating surface) Knocking: Carbon built up in combustion chamber Fuel poor quality or incorrect (Use the gasoline recommended in the Owner's Manual) Spark plug incorrect Ignition coil trouble IC igniter in ECU trouble Inlet air temperature sensor trouble Miscellaneous: Throttle valve won't fully open Actions (chapter) Tighten (see chapter 5)Adjust (see chapter 2)Inspect and replace (see chapter 5)Inspect and replace (see chapter 5)Inspect and replace (see chapter 5)Replace (see chapter 5) Inspect and replace (see chapter 5)Inspect and replace (see chapter 5)Inspect and repair or replace (see chapter 5)