Maintenance
WP33L_BA_K1_12_en_08.fm
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8.9 Checking the piston rings
1. Remove cylinder heads and valves as described in Chapter
8.8 “Checking valves”.
2. Remove cylinder base nuts and pull off the cylinder carefully.
Hold the piston while the cylinder comes off.
3. Remove circlips to release gudgeon pins, push out gudgeon
pin and take piston off.
4. Remove all piston rings from the respective pistons.
5. Insert the piston rings in the respective cylinder and measure
the gap clearance with a feeler gauge.
6. Replace all piston rings if the gap clearance of one ring ex-
ceeds the following limits.
7. Install piston rings to the respective piston. Make sure they
are in the correct position: piston rings having an asymmetric
cross section are marked on one of the surfaces with “TOP”.
The marked face must be at the top when the piston ring is
installed. See illustration.
Note!
If the piston is not held, when pulling the cylinder off, it will fall
against the crankcase.
1
st
stage all piston rings 0.90 mm
2
nd
stage Nose ring 0.55 mm
Plain ring 0.55 mm
Oil scraper ring 0.40 mm
Note!
Always replace all
pistons rings of a piston when one of the pis-
ton rings exceeds the limit.
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