30/ENGINE - WORK ON INDIVIDUAL PARTS 120
19.15Checking piston/cylinder mounting clearance
– Check/measure the cylinder. ( p. 118)
– Check/measure the piston. ( p. 118)
– The smallest piston/cylinder mounting clearance is the result of the smallest cylinder bore diameter minus the largest piston diam-
eter. The largest piston/cylinder mounting clearance is the result of the largest cylinder bore diameter minus the smallest piston
diameter.
Guideline
Piston/cylinder - mounting clearance
New condition 0.035… 0.060 mm (0.00138… 0.00236 in)
Wear limit 0.10 mm (0.0039 in)
19.16Checking oil pumps for wear
Info
The oil pump wear check shown here is on the suction pump but it applies to all oil pumps.
300106-10
– Use a feeler gauge  to measure the play between the external rotor and the
engine case as well as between the external rotor and the internal rotor.
Oil pump
Clearance between external rotor
and engine case
≤ 0.20 mm (≤ 0.0079 in)
Clearance between external rotor
and internal rotor
≤ 0.20 mm (≤ 0.0079 in)
Axial clearance 0.04… 0.08 mm (0.0016…
0.0031 in)
» If the measured value does not meet specifications:
– Change the oil pump and, if necessary, the engine case.
19.17Replacing autodecompressor
300107-10
– Take the lock ring  off the autodecompression shaft and dispose of it.
300108-10
– Pull the autodecompression shaft  from the camshaft.
300109-10
– Disconnect the autodecompression spring. Loosen the screw  and remove it
together with the autodecompression spring and the autodecompression weight.
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