BOMBARDIER Johnson 90 Service Manual page 201

POWER UNIT
CYLINDER / CRANKSHAFT / PISTON
Cylinder bore
lnspect cylinder walls for scratches, roughness, or ridges
which indicate excessive wear. lf cylinder bore is very rough
or deeply scratched, or ridged, rebore cylinder and use over­
size piston.
Cylinder bore wear (dlfference)
Using cylinder gauge, measure cylinder bore in both axial
(vertical line, following crankshaft) and transverse (horizontal
line across crankshaft) directions at two positions as shown
in figure.
1®1
Cylinder gauge set
Check for following:
• Difference between measurements at the two positions
(taper).
• Difference between axial and transverse measurement
(out-of-round).
Cylinder bore wear (difference):
Servlce limit: 0.10 mm (0.039 in)
lf measurement exceeds service limit, rebore or replace cyl­
inder.
PISTON TO CYLINDER CLEARANCE
1. Measure piston diameter at a point 26.5 mm (1.04 in)
above piston skirt ata right angle to piston pin bore.
1Mh
Mlcrometer
Plston skirt dlameter:
Standard 90/115: 83.970- 83.990 mm (3.3059- 3.3067 in)
Standard 140: 85.970-85.990 mm (3.3846- 3.3854 in)
2. Measure cylinder bore at 50 mm (2.0 in) below cylinder
head gasket surface ata right angle to crankshaft pin.
5D
Cylinder gauge set
Cylinder bore:
Standard 90/115: 84.000 - 84.020 mm (3.3071 - 3.3079 in)
Standard 140: 86.000 - 86.020
mm
(3.3858 - 3.3866 in)
• I
1. 50 mm (1.96 In)
2. 90
mm
(3.54
in)
6-47