BRP Johnson 4HP Service Manual page 101

Conrod big end oil clearance
Check the clearance as follows.
1. Clean the surface of the conrod, the conrod cap and the
crank pin.
2. Place a piece of the Plastigage on the crank pin parallel
to the crankshaft, avoiding the oil hole.

Plastigage
3. Install the conrod and the conrod cap to the crank pin.
4. Install the two conrod bolts and tighten the bolts to the
specified torque in two steps.
NOTE:
Do not rotate the conrod with the Plastigage in place.

Conrod bolt:
1st step 10 N·m (1.0 kg-m, 7.0 lb-ft)
2nd step 20 N·m (2.0 kg-m, 14.5 lb-ft)
5. Remove the conrod and the conrod cap from the crank
pin.
6. Using the scale on the Plastigage envelope, measure the
Plastigage with the widest point.
Conrod big end oil clearance:
Standard: 0.015 – 0.035 mm (0.0006 – 0.0014 in)
Service limit: 0.080 mm (0.0031 in)
If the measurement exceeds the service limit, replace the
conrod assembly and/or crankshaft.
Conrod big end inside diameter:
Standard: 28.015 – 28.025 mm (1.1030 – 1.1033 in)
PISTON PIN / CONROD / CRANKSHAFT
POWERHEAD
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