KYMCO Dink 50, Service Manual

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7
. CYLINDER/PISTON
7-4
DINK50/ 125
SPECIFICATIONS(DINK 50)
Unit: mm (in)
Item
Standard Service Limit
I.D.
39.00
～
39.01 (1.560
～
1.5604) 39.1(1.564)
Warpage
⎯
0.05 (0.002)
Cylindricity
⎯
0.05 (0.002)
True roundness
⎯
0.05 (0.002)
Ring-to-groove Top
0.015
～
0.055 (0.006
～
0.002) 0.09 (0.0036)
clearance
Second
0.015
～
0.055(0.006
～
0.002) 0.09 (0.0036)
Top
0.10
～
0.3 (0.004
～
0.012) 0.5 (0.02)
Piston, Ring end gap Second
0.10
～
0.3 (0.004
～
0.012) 0.5 (0.02)
piston ring Oil side rail
0.2
～
0.7 (0.008
～
0.032)
⎯
Piston O.D. 39.985
～
39.995(1.5994
～
1.5998) 39.9 (1.596)
Piston O.D. measuring position
9 mm (0.36 in) from bottom of skirt
⎯
. Piston-to-cylinder clearance 0.01
～
0.04 (0.0004
～
0.0016) 0.1 (0.004)
Piston pin hole I.D. 13.002
～
13.008 (0.52008
～
0.52032) 13.04 (0.536)
Piston pin O.D 14.994
～
15 (0.59976
～
0.6) 14.96 (0.5984)
Piston-to-piston pin clearance 0.002
～
0.014 (0.00008
～
0.00056) 0.02 (0.0008)
Connecting rod small end I.D. bore 13.016
～
13.034 (0.52064
～
0.52136) 13.06 (0.5224)
Cylinder
TROUBLESHOOTING
•
When hard starting or poor performance at low speed occurs, check the crankcase breather for
white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken.
Compression too low or uneven
compression
Excessive smoke from exhaust muffler
•
Worn or damaged cylinder and piston rings
•
Worn or damaged piston rings
•
Worn, stuck or broken piston rings
•
Worn or damaged cylinder and piston
Compression too high Abnormal noisy piston
•
Excessive carbon build-up in combustion
•
Worn cylinder, piston and piston rings
chamber or on piston head
•
Worn piston pin hole and piston pin
•
Incorrectly installed piston