18
30/ENGINE
123
Info
Piston dimensions
1
are marked on the piston head.
18.4.10 Checking the piston ring end gap
202787-10
–
Remove the piston ring from the piston.
–
Place the piston ring in the cylinder and align with the piston.
Guideline
Below the upper edge of the cylinder
20 mm (0.79 in)
–
Measure end gap
A
with a feeler gauge.
Guideline
Piston ring - end gap
Ring 1
≤
0.40 mm (
≤
0.0157 in)
Ring 2
≤
0.40 mm (
≤
0.0157 in)
» If the end gap is greater than the specified measurement:
–
Check/measure the cylinder. (
» If cylinder wear lies within the specified tolerance:
–
Change the piston ring.
–
Mount the piston ring with the marking facing toward the piston head.
18.4.11 Piston/cylinder - measuring the mounting clearance
202785-10
–
Check/measure the cylinder. (
–
Check/measure the piston. (
–
The smallest piston/cylinder mounting clearance equals the smallest cylinder bore
diameter minus the largest piston diameter. The largest piston/cylinder mount-
ing clearance equals 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)
Piston/cylinder - mounting clearance
Wear limit
0.10 mm (0.0039 in)
18.4.12 Checking the reed valve housing, reed valve, and intake flange
308688-10
–
Check intake flange
1
for damage and wear.
» If there is damage or wear:
–
Change the intake flange.
–
Check membrane
2
for damage and wear.
» If there is damage or wear:
–
Change the membrane.
–
Check reed valve housing for damage and wear.
» If there is damage or wear:
–
Change the reed valve housing.