Crankshaft; Piston - Stihl BR 500 Service Manual

7.9.3

Crankshaft

Always check and, if necessary,
repair the fuel system, carburetor,
air filter and ignition system before
looking for faults on the engine. See
also "Troubleshooting", b 4.
– Remove the lower half of the
crankcase, b 7.9.2
3
: Lift the crankshaft (1) and pull the
piston out of the cylinder at the
same time.
: Pull off the oil seals (2 and 3).
– Inspect cylinder running face for
signs of damage and serious
scores. Install new cylinder with
piston if necessary, b 7.9.7
40
3
1
: Examine ball bearings (1),
connecting rod (2) and gear (3).
– If one of these parts is damaged,
install a new crankshaft
assembly.
Install in the reverse sequence.
2 1
– Coat piston and piston rings with
oil.
– Fit piston rings so that their gaps
are offset 120 degrees.
– Use new oil seals.
– Lubricate sealing lips of oil seals
with grease, b 13.
– Apply thin coating of sealant to
outer diameter of oil seals, b 13.
– Carefully fit piston in the cylinder.
– Install the crankshaft with new oil
seals in the cylinder.
– Fit lower half of crankcase,
b 7.9.2
– Align the flywheel and fit the cam
gear, b 7.5
Install all other parts in the reverse
sequence.
7.9.4

Piston

2
1
– Remove the crankshaft, b 7.9
Always wear safety glasses when
working with spring washers and
snap rings.
: Use a suitable tool to ease the
hookless snap ring out of the
groove.
1
: Use the assembly drift (2)
1110 893 4700 to push the piston
pin (1) out of the piston.
BR 500, BR 550, BR 600
2