KYMCO AHG5, Service Manual

Page: 74 / 363

6. CYLINDER HEAD/ VALVE
DT X360
6-3
2. SERVICE INFORMATION
2.1. GENERAL INSTRUCTIONS

The cylinder head can be serviced with the engine installed in the frame. Coolant in the
radiator and water jacket must be drained first.

When assembling, apply molybdenum disulfide grease or engine oil to the valve guide
movable parts and valve arm sliding surfaces for initial lubrication.

The valve rocker arms are lubricated by engine oil through the cylinder head engine oil
passages. Clean and unclog the oil passages before assembling the cylinder head.

After disassembly, clean the removed parts and dry them with compressed air before
inspection.

After removal, mark and arrange the removed parts in order. When assembling, install
them in the reverse order of removal.
2.2. SPECIFICATIONS
Unit: mm
Item Standard Service Limit
Valve clearance (cold)
IN 0.1

EX 0.1

Cylinder head compression pressure
12
±
2 kgf-cm2

Camshaft cam height
IN 34.2987 33.89
EX 34.1721 33.77
Valve rocker arm I.D.
IN 10.0~10.015 10.10
EX 10.0~10.015 10.10
Valve rocker arm shaft O.D.
IN 9.972~9.987 9.91
EX 9.972~9.987 9.91
Valve seat width
IN 1.2 2.0
EX 1.2 2.0
Valve stem O.D.
IN 4.975~4.990 4.90
EX 4.955~4.970 4.90
Valve guide I.D.
IN 5.00~5.012 5.30
EX 5.00~5.012 5.30
Valve stem-to-guide clearance
IN 0.010~0.037 0.08
EX 0.030~0.057 0.10