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Air-cooled two-stroke engine 2 A . 3
General i
The engine unit is a single cylinder two-
stroke, with fan assisted air cooling. The fan is
mounted on the alternator rotor, which is on
the right-hand end of the crankshaft. The
crankshaft assembly is pressed together,
incorporating the connecting rod, with the
big-end running on the crankpin on a needle
roller bearing. The piston also runs on a
needle roller bearing fitted in the small-end of
the connecting rod. The crankshaft runs in
caged ball main bearings. The crankcase
divides vertically.
2 Operations possible with the
I
the fram
All components and assemblies, with the
exception of the crankshaft assembly and its
bearings, can be worked on without having to
remove the engine/transmission unit from the
frame. If however, a number of areas require
attention at the same time, removal of the
engine is recommended, as it is an easy task
to undertake.
Operatio1
removal
ns requiri ing engin'
To access the crankshaft assembly and the
engine main bearings, the engine must be
removed from the frame and the crankcase
halves must be separated.
4 Major engine repair
-
~leneral
note
1 It is not always easy to determine when or if
an engine should be completely overhauled,
as a number of factors must be considered.
2 High mileage is not necessarily an
indication that an overhaul is needed, while
low mileage, on the other hand, does not
preclude the need for an overhaul. Frequency
of servicing is probably the single most
important consideration. An engine that has
regular and frequent maintenance will most
likely give many miles of reliable service.
Conversely, a neglected engine, or one which
has not been run in properly, may require an
overhaul very early in its life.
3 If the engine is making obvious knocking or
rumbling noises, the connecting rod and/or
main bearings are probably at fault.
4 Loss of power, rough running, excessive
noise and high fuel consumption rates may
also point to the need for an overhaul,
especially if they are all present at the same
time. If a complete tune-up does not remedy
the situation, major mechanical work is the
only solution.
5 An engine overhaul generally involves
restoring
the
internal
parts
to
the
specifications of a new engine. This may
require fitting new piston rings and crankcase
seals, or, after a high mileage, renewing the
crankshaft and connecting rod assembly. The
end result should be a like-new engine that
will give as many trouble-free miles as the
original.
6 Before beginning the engine overhaul, read
through the related procedures to familiarise
yourself with the scope and requirements of
the job. Overhauling an engine is not all that
difficult, but it is time consuming. Check on
the availability of parts and make sure that
any necessary special tools and materials are
obtained in advance.
7 Most work can be done with typical
workshop hand tools, although Peugeot
produce a number of service tools for specific
purposes such as separating the crankcase
halves. Precision measuring tools are required
for inspecting parts to determine if they must
be renewed. Alternatively, a Peugeot dealer
will handle the inspection of parts and offer
advice
concerning
reconditioning
and
replacement. As a general rule, time is the
primary cost of an overhaul so it does not pay
to install worn or substandard parts.
8 As a final note, to ensure maximum life and
minimum trouble from a rebuilt engine,
everything must be assembled with care in a
spotlessly clean environment.
5 Engine-
removal
and insra~~arlor.
Caution: The engine i s not heavy, however
engine removal and installation should be
carried out with the aid o f an assistant;
personal injury o r damage could occur if
the engine falls or i s dropped.
Removal
1 Support the machine securely in an upright
position. Work can be made easier by raising
the machine to a convenient working height
on an hydraulic ramp or a suitable platform.
Make sure it is secure and will not topple over.
2 Remove body
panels as necessary
according to model (see Chapter 7).
3 Remove the exhaust system (see Chapter 4).
4 If the engine is dirty, particularly around its
mountings, wash it thoroughly before starting
any major dismantling work. This will make
work much easier and rule out the possibility
of dirt falling into some vital component.
5 Disconnect the battery negative terminal
(see Chapter 9) and pull the spark plug cap off
the plug.
6 Trace the wiring from the altemator/ignition
pulse generator coil and the starter motor on
the right-hand side of the engine and
5.10 Remove the oil pump cable and
bracket
disconnect it at the connectors. Free the
wiring from any clips on the frame.
7 Remove the air filter housing and the air
intake duct (see Chapter 4).
8 Disconnect the fuel pipe and fuel tap
vacuum pipe from their unions on the
carburettor and inlet manifold respectively.
Release the clip securing the oil outlet hose to
the carburettor and wrap a clean plastic bag
around the end to prevent dirt entering the
system, then displace the carburettor (see
Chapter 4).
9 Undo the bolts securing the engine and fan
cowlings and remove the cowlings (see
Chapter 3).
10 Where fitted, detach the oil pump control
cable from the pump pulley (see Section 13),
then unscrew the bolts securing the oil pump
control cable bracket and remove the bracket
with the cable attached (see illustration).
Refit the bolts to secure the nuts on the
underside of the pump mounting and to retain
the pump in place.
11 Release the clip securing the oil inlet hose
from the oil tank to the union on the oil pump
and detach the hose (see Section 13). Clamp
the hose and secure it in an upright position to
minimise oil loss. Wrap a clean plastic bag
around the end to prevent dirt entering the
system.
12 On models fitted with a drum rear brake,
disconnect the brake cable from the brake arm
(see Chapter 8). Undo the screw securing the
cable clip to the underside of the drive belt
casing and detach the cable (see illustration).
13 On models fitted with a disc rear brake,
remove the rear wheel and displace the brake
5.12 Undo the clip (arrowed) to detach the
brake cable
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