2003 Suzuki LT-Z400 Factory Service Manual, Page 61Get this manual
CYLINDER HEAD Decarbonize the combustion chamberCheck the gasket surface of the cylinder head for distortion straightedge and thickness gaugeTake clearance readat several placesIf clearance reading exceeds the service limit, replace the head with new one09900-20803: Thickness Cylinder head distortion Service Limit: 0.05 mm in)
VALVE STEM RUNOUT Support the valve -blocks and measure the valve stem runout using the dial as shown, If the runout exceeds the service limit, replace the valve with new one00 mm) 09900-20701: stand 09900-21304: V-block set (100 mm) Valve stem runout Service Limit: 0.05 mm in)