KYMCO Mongoose/KXR 250 User Manual

7. CYLINDER HEAD/VALVES
7-2
Mongoose/KXR 250
SERVICE INFORMATION
GENERAL INSTRUCTIONS
• The cylinder head can be serviced with the engine installed in the frame.
• When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts, valve arm and camshaft sliding surfaces for initial lubrication.
• The camshaft is 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.
SPECIFICATIONS
Item Standard (mm) Service Limit (mm)
IN 0.1 ⎯
EX 0.1 ⎯
Cylinder head compression pressure 15±2kg/cm²
Cylinder head warpage ⎯ 0.05
IN 34.287 34.15
EX 34.1721 34.05
Valve rocker arm to shaft clearance
0.034～0.09 0.1
Valve stem-to-guide IN 0.010～0.037 0.06
clearance
EX 0.025～0.052 0.08
IN 30.9 29.4
Valve spring free length
EX 41 39
IN 10.20～11.84k
g
(at 18.05mm) ⎯
Valve spring
compressed force
EX 19.14～22.02kg(at 21.5mm) ⎯
IN 0.8 ⎯
Valve spring tilt
EX 1.07 ⎯
Valve clearance (cold)
Camshaft cam height

KYMCO Mongoose/KXR 250 Specifications

General

Brand	KYMCO
Model	Mongoose/KXR 250
Category	Offroad Vehicle
Language	English