Zenoah GZ3500T, Workshop Manual

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English –
51
Faults and causes
Cutting marks on the piston (H)
1. Wrong carburettor setting. Too high fast idle
speed.
2. Too low octane number of petrol.
3. Too low or incorrect oil in the fuel.
Carbon deposits (J)
1. Wrong carburettor setting. Too low fast idle
speed.
2. Too much or incorrect oil in the fuel.
Piston ring breakage
1. Too high engine speed.
2. Piston ring worn out.
3. Oversized piston ring groove.
Repair instructions
Fig 84
7.24 Assembling the piston and cylinder
1
Oil the needle bearing with two-stroke oil and insert
it into the crank rod, press in the guiding washers,
see figure 81.
Note! When assembling the piston onto the crank
rod, the arrow on the piston should be pointing as
shown in figure 85.
2
Slide in the gudgeon pin E and fasten the circlips
D, see figure 81. Note! Use new circlips.
3
Oil the piston and piston ring with two-stroke oil.
Fit the piston with the arrow pointing towards the
exhaust port S, see figure 87.
4
Compress the piston ring and carefully push the
piston into the cylinder. Put back the seals and the
circlip and screw together the crankcase half and the
cylinder, see figure 87. The screws should be tighte-
ned crosswise with tightening torque 13-15 Nm.
NOTE!
It is very important that the intake system
is leak tight, or the engine may seize up.
Fig 85
5
Insert the cylinder and the crankcase half back into
the plastic bottom. Fit the cylinder cover and tigh-
ten four screws as shown in figures 75 and 76.
Fit the heat shield. Insert and tighten the muffler.
Insert and tighten the inlet bellows using two screws.
Fit the:
• pump unit
• clutch
•
ignition module and flywheel
• tank unit, see ”Assembling the intake system”
• chain, bar and clutch cover
Fig 86
Fig 87