Cylinder/Piston Specifications (Dink 50); Cylinder/Piston Troubleshooting - KYMCO DINK 125 Service Manual

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