Cylinder/Piston Service Information; Cylinder/Piston Troubleshooting; Low Compression Or Uneven Compression; Excessive Smoke - Honda CH250 Elite 1986 Service Manual

7. CYLINDER/PISTON
SERVICE INFORMATION
TROUBLESHOOTING
CYLINDER REMOVAL
SERVICE INFORMATION
GENERAL
PISTON REMOVAL
PISTON INSTALLATION
CYLINDER INSTALLATION
7-3
7-6
7-7
• The
cyliindl~r
and piston can be serviced with the engine in the frame.
SPECIFICATIONS
ITEM
STANDARD mm (inl SERVICE LIMIT mm (in)
1.0. 72.000- 72.01 0 12.8346- 2.8350) 72.10(2.839)
v
0.05 (0.002)
Piston,
0:
Top
0.015--0.050 (0.0006-0.00201 0.09 (0.004)
.
" "
.
Piston
I
Second
..
0.015-0.050 (0.0006-0.0020) 0.09 10.004)
..
gap Top 10.15-0.35 (0.006·-0.014) 0.50 (0.020)
Second
0.15-0.35 (0.006-0.0141 0.50 (0.020)
Oil (Side raill 0.2-0.7 (0.01--0.03)
--
Piston 0.0.
I? Q~~l:! .? Q~.lI?1
71.90 (2.831)
. - -
Piston-ta-cylinder
IA.A AliA 'A AAAil .A riA
6)
0.10 (0.004)
Piston pin bore '.002
'.008
1r1 "",,,....
f'\
&:&:Q&ll
17.04 (0.671)
- -
Piston pin
0.0.
16.994-17.000 (0.6691 -0.6693) 16.96 (0.668)
f' > '
pil clearance 0.002-0.014 (0.0001-0.0006) 0.02 (0.001)
.
~
." rod small end
1.0. 17.016 17.034 (0.6699 0.6706) 17.06 (0.6721
TROUBLESHOOTING
low compression or uneven compression
• Worn cylinder or rings
Excessive smoke
• Worn piston or piston rings
ImllYOlperly installed piston
Dalns!Jed piston or cvliind':lr
Overheating
• Excessive carbon on piston head
Blocke,d or restricted flow of coolant
Stj(~kirlg
thermostat
Kl1lCtck:ing or abnormal noise
• Worn and cyliindl:lf
• Excessive carbon on piston head
7-1