Comperssion Too Low; Overheating; Excessive Smoke; Abnormal Noise - DAELIM Besbi SC125 Service Manual

10. CYLINDER / PISTON

SERVICE INFORMATION
TROUBLE SHOOTING
CYLINDER
SERVICE INFORMATION
GENERAL SAFETY
Be careful not to damage the mating surfaces by using a screwdriver when disassembling the cylinder. Do not strike the
cylinder too hard during disassembly, even with a rubber or plastic mallet, to prevent the possibility of damage to the
cylinder fins.
Take care not to damage the cylinder wall and piston.
Check parts after disassembling, and clean and dry with an air hose prior to taking measurements.
SPECIFICATIONS
CYLINDER
PISTON SKIRT OUTER DIAMETER
PISTON PIN HOLE INNER DIAMETER
PISTON,
PISTON-TO-PISTON PIN CLEARANCE
PISTON PIN,
PISTON RING-TO-
PISTON RING
GROOVE CLEARANCE
PISTON RING
JOINT GAP
CYLINDER-TO-PISTON CLEARANCE
CONNECTING ROD SMALL END INNER DIAMETER
GAP BETWEEN CONNECTING ROD SMALL END AND PISTON PIN
TROUBLE SHOOTING

Comperssion too low

Worn piston
Worn, damaged piston ring
Worn cylinder

Excessive smoke

Worn cylinder, piston or piston rings
Improper installation of piston ring
Scored or scratched piston or cylinder wall
10-1
10-1
10-2
ITEM
INNER DIAMETER
TAPER
OUT-OF-ROUND
HEAD CONTACT WARPAGE
PISTON PIN OUTER DIAMETER
SECOND
TOP / SECOND
OIL RING (SIDE RAIL)
PISTON / PISTON RING
CYLINDER INSTALLATION
STANDARD VALUE
52.400-52.410 mm
52.370-52.390 mm
15.002-15.008 mm
14.996-15.000 mm
0.002-0.014 mm
TOP 0.03-0.07 mm
0.02-0.06 mm
0.15-0.30 mm
0.20-0.70 mm
0.015-0.045 mm
15.002-15.013 mm
0.002-0.014 mm

Overheating

Excessive carbon build-up on top of piston

Abnormal noise

Worn cylinder and piston
Worn connecting rod small end bearing or piston pin
Damaged piston ring
Excessive carbon build-up on top of piston
10-3
10-6
Unit : mm
SERVICE LIMIT
52.500 mm
- 0.050 mm
- 0.005 mm
- 0.05 mm
52.30 mm
15.040 mm
14.960 mm
0.105 mm
0.095 mm
0.050 mm
0.50 mm
-
0.105 mm
15.037 mm
0.020 mm
10-1