BOMBARDIER 1980 Shop Manual page 143

TOP END
CLEANING
Discard all gaskets.
C!ean all metal components in a non-ferrous metal
cleaner.
Scrape off carbon formation from cylinder exhaust port.
cylinder head and piston dome using a wooden spatula.
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NOTE: The letters "AUS" (over an arrow on the
piston dome) must be visible after cleaning.
Clean the piston ring grooves with a groove cleaner tool.
or with a piece of broken ring.
DISASSEMBLY & ASSEMBLY
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NOTE: Refer to Technical Data for component fitted
tolerance and wear limit.
00
00When installing cylinder andlor cylinder head.
the cylinder aligning tool must be used to ensure sealing
of intake manifold and exhaust. (See Tools Section).
Install muffler on exhaust socket then install aligning bar.
Cross torque cylinder head nuts to 20 Nom (15 It-Ibs).
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NOTE: Torque each cylinder head individually.
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Cylinder
ahgning
__ tool
0®Torque cylinder head nuts to 20 Nom (15 ft-Ibs).
@@®Torque to 20 Nom (15 ft-Ibs).
®@®Place a clean cloth over crankcase to prevent
Clrclips from falling into crankcase. Use a pointed tool
to remove eirel ips from piston .
. . , CAUTION: When tapping out gudgeon pins, hold
' " piston firmly in place to eliminate the possibilities
of transmitting shock and pressure to the connnecting
rod.
At assembly. place the pistons over the connecting rods
with the letters "AUS" (over an arrow on the piston dome)
facing in direction of the exhaust port.
EXHAUST
SECTION 03
SUB-SECTION 02, (ENGINES)
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Also make sure that the piston windows are aligned with
the crankcase transfer passages when the gudgeon pin
orifice is in-line
with
the connecting rod bore.
Piston
windows
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NOTE: Once circlips are installed turn each wclip
so the circlip break is not directly on piston notch.
Remove any burrs from piston caused through circlip
installation using very fine emery cloth.
Piston notch
Piston to cylinder wall clearance should be:
MINIMUM - MAXIMUM
0.070 - 0.220 mm
(0028") - (.0086")
(640 ENGINE TYPE). PAGE 7