4
. CYLINDER HEAD/VALVES
2
BR & M2 250 ENGINE
SERVICE INFORMATION
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.
SPECIFICATIONS
Standard (mm)
Service Limit (mm)
Item
SH50CA
SH50CA
IN
0.10
EX
0.10
Cylinder head compression pressure
15kg/cm
²
Cylinder head warpage
0.05
IN
34.2987
34.14
EX
34.1721
34.02
IN
10.00
∼
10.015
10.10
EX
10.00
∼
10.015
10.10
Valve rocker arm shaft
IN
9.972
∼
9.987
9.9
O.D.
EX
9.972
∼
9.987
9.9
IN
1.2
1.8
EX
1.2
1.8
IN
4.990
∼
4.975
4.925
EX
4.970
∼
4.955
4.915
IN
5.00
∼
5.012
5.03
EX
5.00
∼
5.012
5.03
Valve stem-to-guide
IN
0.010
∼
0.037
0.08
clearance
EX
0.030
∼
0.057
0.10
TORQUE VALUES
Cylinder head cap nut
19.6N-m
Apply engine oil to threads
Valve clearance adjusting nut
8.8N-m
Apply engine oil to threads
Cylinder head cover bolt
7.8
∼
11.8N-m
SPECIAL TOOLS
Valve spring compressor
Valve seat cutter, 24.5mm
45
°
IN-EX
Valve seat cutter, 25mm
Plane cutter 37.5
°
EX
Valve seat cutter, 22mm
Plane cutter 37.5
°
EX
Valve seat cutter, 26mm
Plane cutter 63.5
°
IN/EX
Cutter clip
Valve guide driver
Valve guide reamer
Valve clearance (cold)
Camshaft cam height
Valve rocker arm I.D.
Valve guide I.D.
Valve stem O.D.
Valve seat width
Summary of Contents for Bug Rider BR-250
Page 1: ...BR 250 BR 250SS M2 250 SERVICE MANUAL Manufactured by PGO of Motive Power Industry Co Ltd...
Page 34: ...4 CYLINDER HEAD VALVES 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 46: ...5 CYLINDER PISTON 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 55: ...6 DRIVE AND DRIVEN PULLEYS KICK STARTER 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 71: ...7 FINAL REDUCTION 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 82: ...8 CARBURETOR BR M2 250 ENGINE...
Page 90: ...9 A C GENERATOR STARTER CLUTCH 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 97: ...10 CRANKCASE CRANKSHAFT 1 BR M2 250 ENGINE SCHEMATIC DRAWING...
Page 103: ...10 CRANKCASE CRANKSHAFT 7 BR M2 250 ENGINE Torque 7 8 11 8N m Cam Chain Tensioner Slipper Bolt...
Page 105: ...11 COOLING SYSTEM 1 BR M2 250 ENGINE SCHEMATIC DRAWING...