English - 39
Piston and cylinderr
8. Remove the circlips (A) and press out the gudgeon
pin (B). Remove the piston. See Figure 3.
9. Remove the piston ring (C).
18.2 Cleaning and inspection
Clean all parts, scrape off all the remains of any gasket
material and scrape off carbon deposits from the follo-
wing surfaces:
1. The piston crown.
2. Top of the cylinder bore (inside).
3. The cylinder exhaust port.
4. The decompression valve.
5. Base of the cylinder and/or crankcase
Check the following:
1. That the cylinder’s surface coating is not worn. Es-
pecially in the upper end of the cylinder.
2. That the cylinder is free of score marks. See figure
4.
3. That the piston is free of score marks. Minor
scratches can be polished off with fine emery paper.
4. That the piston ring is not burnt into its groove.
5. Measure the wear on the piston ring by placing it the
cylinder and measuring the gap. See figure 5. The
clearance must not exceed 1 mm.
6. That the needle bearing is undamaged.
Fig. 3
A
B
C
A
Fig. 4
Fig. 5