Yanmar BY Series Service Manual page 104

Camshaft and Timing Gear Train
Adjusting Camshaft Timing
Figure 5-73
1. Rotate the crankshaft until No. 1 cylinder intake
camshaft lobes are facing down.
IMPORTANT
Do not remove the camshaft sprocket bolts.
Note: One bolt must be loosened prior to
rotating No. 1 piston to TDC position.
2. Loosen one bolt (Figure 5-73, (1)).
Figure 5-74
3. Rotate the crankshaft in the normal running
direction until No. 1 cylinder is at TDC of the
power stroke. The front lobe of each camshaft
(Figure 5-74, (1)) will be facing toward the
exhaust side and the timing marks
(Figure 5-74, (2)) will meet.
BY Service Manual
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0003774
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0003771
4. Verify position by checking the camshaft timing
marks (Figure 5-74, (2)) on gears are aligned.
The single mark on intake camshaft gear must
fall between the two marks on the exhaust
camshaft gear.
Figure 5-75
IMPORTANT
DO NOT rotate the crankshaft backward. If
the crankshaft is turned past TDC, rotate
two more turns (720°) to bring No. 1 piston
back to TDC.
5. Secure crankshaft in TDC position with flywheel
holding tool (Figure 5-71).
Figure 5-76
6. Loosen two remaining bolts (Figure 5-76, (1)).
ENGINE
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