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Air-cooled two-stroke engine 2A.15
14.32a Ensure crankcase halves are seated on the gasket
14.32b Position of main bearings can be checked through oilways
(arrowed)
protect the aluminium and use the set-up
shown in Step 29 (see illustration 14.29~). If
the main bearing is on the crankshaft, heat the
bearing housing with a hot air gun before
fitting the crankcase half. Note: Avoid
applying direct heat onto the crankshaft oil
seal.
32 Check that the crankcase halves are
seated on the gasket and that the main
bearings are pressed fully into their housings
(see illustrations). If the casings are not
correctly seated, heat the bearing housings
while applying firm pressure with the
assembly tools used previously. Note: Do not
attempt to pull the crankcase halves together
using the crankcase bolts as the casing will
crack and be mined.
33 Clean the threads of the crankcase bolts
and install them finger-tight, then tighten them
evenly a little at a time in a criss-cross
sequence to the torque setting specified at
the beginning of this Chapter (see illustration
14.3). Rotate the crankshaft by hand - if there
are any signs of undue stiffness, tight or rough
spots, or of any other problem, the fault must
be rectified before proceeding further.
34 Trim the crankcase gasket flush with the
mating surface for the cylinder (see illustration).
35 Lubricate the oil pump drive shaft and
install the shaft and the shaft bush; tap the
bush into its seat with a hammer and suitable
sized socket (see illustrations). Rotate the
crankshaft to ensure the oil pump drive gears
are correctly engaged.
36 Install all other assemblies in the reverse
order of removal.
5 If the engine proves reluctant to start,
remove the spark plug and check that it has
not become wet and oily. If it has, clean it and
try again. If the engine refuses to start, go
through the fault finding charts at the end of
this manual to identify the problem.
unning-ir
i
Recomr
procedi
nended r
Ire
p after
oi
1 Treat the engine gently for the first few
miles to allow any new parts to bed in.
2 If a new piston, rings or cylinder has been
fitted, the engine will have to be run in as
when new. This means a restraining hand on
the throttle until at least 300 miles (500 km)
have been covered. There's no point in
keeping to any set speed limit
-
the main idea
is to keep from labouring the engine and to
gradually increase performance up to the 600
mile (1000 km) mark. Make sure that the
throttle position is varied to vary engine
speed, and use full throttle only for short
bursts. Experience is the best guide, since it's
easy to tell when an engine is running freely.
1 Make sure the oil tank is at least partly full
and the pump is correctly adjusted (see
Chapter 1) and bled of air (see Section 13).
2 Make sure there is fuel in the tank.
3 With the ignition OFF, operate the kickstart
to check that the engine turns over easily.
4 Turn the ignition ON, start the engine and
allow it to run at a slow idle until it reaches
operating temperature. Do not be alarmed if
there is more than the usual amount of smoke
from the exhaust
-
this will be due to the oil
used to lubricate the engine components
during assembly and should subside after a
while.
14.34 Trim off any excess gasket
14.35a Install the oil pump shaft
. . .
14.35b
. .
.
and shaft bush
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