Cylinder Head Distortion; Valve Seat Width; Valve Stem And Valve Guide; Valve Stem Deflection - Linhai T-Boss 550 Service Manual

CHAPTER 3 ENGINE

Cylinder Head Distortion

Clean off carbon deposit from combustion chamber;
Check the gasket surface of the cylinder head for
distortion with a straightedge and thickness gauge. Take
clearance readings from several places. If any clearance
reading is out of the service limit, replace with a new
cylinder head.
Cylinder Head Distortion Service Limit: 0.05mm
Tool: Thickness Gauge

Valve Seat Width

Coat the valve seat with color uniformly. Fit the
valve and tap the coated seat with the valve face in
a rotating manner. To get a clear impression of the
seating contact, use a valve lapper to hold the valve
head.
The ring-like dye impression on the valve face
should be continuous, without any break. The width
of the dye ring, which is the visualized seat width,
should be within the following range:
Valve Seat Width: 0.9-1.1mm
Tool: Valve Lapper

Valve Stem and Valve Guide

Lift the valve about 10mm from valve seat. Check
the valve stem deflection in the directions of X and Y
perpendicular to each other, with a dial gauge. If the
deflection measured is out of the limit, replace either
the valve or the valve guide. (If the valve stem is
worn to the limit and the clearance is found to be in
excess of the limit, replace the valve. If the valve
stem is within the limit, replace the valve guide.
Double check the clearance after replacing the
valve stem or the guide).
Valve Stem Deflection (IN & EX): 0.35mm
Tool: Micrometer
Magnetic Stand
T-Boss550 SERVICE MANUAL20.0
CHAPTER 3 ENGINE PAGE. 3- 50