Precautions In Operation; Troubleshooting - Sym MAXSYM 400i Service Manual

7. Cylinder / Piston

Precautions in Operation

General Information
Both cylinder and piston service cannot be carried out when engine mounted on frame.
Specification
Item
I.D.
Out of round
Cylinder
Taper
Warpage
Clearance
between
piston ring and
ring groove
Piston/
Piston ring end
gap
Piston
ring
Piston O.D. (2
Clearance between piston
and cylinder
ID of piston pin boss
Piston pin O.D.
Clearance between piston and piston pin
Connecting rod small end I.D.

Troubleshooting

Low or Unstable Compression Pressure
Cylinder or piston ring worn out
Knock or Noise
Cylinder or piston ring worn out
Carbon deposits on cylinder head top-side
Piston pin hole and piston pin wear out
7-2
To this chapter contents
Standard
70.995~71.015
Top 0.015~0.050
nd
2 0.015~0.050
Too 0.150~0.300
nd
2 0.300~0.450
Oil
0.200~0.700
(side rail)
nd
) 70.430~70.480
0.010~0.040
17.002~17.008
16.994~17.000
0.002~0.014
17.016~17.034
LM25W5
Limit
71.100
- 0.050
- 0.050
- 0.050
0.090
0.090
0.500
0.650
-
70.380
0.100
17.020
16.960
0.020
17.064
Smoking in Exhaust Pipe
Piston or piston ring worn out
Piston ring installation improperly
Cylinder or piston damage
Engine Overheat
Carbon deposits on cylinder head top side
Cooling pipe clogged or not enough in coolant
flow
Unit： ： ： ： mm
LM30W
Standard Limit
72.995~73.015 73.100
- 0.050
- 0.050
- 0.050
0.015~0.050 0.090
0.015~0.050 0.090
0.150~0.300 0.500
0.300~0.450 0.650
0.200~0.700
72.430~72.480 72.380
0.010~0.040 0.100
17.002~17.008 17.020
16.994~17.000 16.960
0.002~0.014 0.020
17.016~17.034 17.064
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