Camshaft - BRP Johnson 4HP Service Manual

CAMSHAFT

Cam face
Inspect the cam face for scratches and wear.
Cam wear
Measure the cam height H.
 Micrometer
Cam height:
Standard:
IN 32.401 – 32.461 mm (1.2756 – 1.2780 in)
EX 32.538 – 32.598 mm (1.2810 – 1.2834 in)
Service limit:
IN 32.101 mm (1.2638 in)
EX 32.238 mm (1.2692 in)
If the measurement exceeds the service limit, replace the
camshaft.
Camshaft journal oil clearance
To check the clearance, measure the following items.
•
Camshaft journal (upper and lower) outside diameter.
•
Camshaft holders (cylinder block and crankcase) inside
diameter.
 Micrometer
Dial caliper
Camshaft journal oil clearance:
Standard:
Upper 0.016 – 0.062 mm (0.0006 – 0.0024 in)
Lower 0.016 – 0.052 mm (0.0006 – 0.0020 in)
Service limit:
Upper 0.150 mm (0.0059 in)
Lower 0.150 mm (0.0059 in)
If the clearance exceeds the service limit, replace the cam-
shaft, the cylinder block and/or the crankcase.
Camshaft holder inside diameter:
Standard:
Upper 15.000 – 15.028 mm (0.5906 – 0.5917 in)
Lower 16.000 – 16.018 mm (0.6299 – 0.6306 in)
Camshaft journal outside diameter:
Standard:
Upper 14.966 – 14.984 mm (0.5892 – 0.5899 in)
Lower 15.966 – 15.984 mm (0.6286 – 0.6293 in)
POWERHEAD
CAMSHAFT
6-19