Yamaha F400A 2022 - Checking the Sprocket; Checking the Cam Chain; Checking the Cam Chain Tensioner

Camshaft
7-49
7. Remove:
• Camshafts
• Valve lifters
TIP:
Make sure to keep the parts in the order of re-
moval.
Checking the sprocket
1. Check:
• Driven sprocket
• Camshaft (EX)
• VCT assembly
Cracked/damaged/worn → Replace the
driven sprocket, camshaft (EX), or VCT as-
sembly.
Checking the cam chain
1. Check:
Chain length
Above specification → Replace.
a. Measure the distances “a” and “b” for
a 12-link section of the cam chain, and
then calculate the chain length using
the following formula.
TIP:
When measuring the chain length, make sure
that the chain is sufficiently taut without any
slack.
Calculation formula:
Chain length of the measured section =
(Distance “a” between the inner edges
of the rollers + Distance “b” between
the outer edges of the rollers)/2
Example:
Distance “a” between the inner edges
of the rollers = 108.25 mm
Distance “b” between the outer edges
of the rollers = 120.55 mm
Chain length of the measured section =
(108.25 mm + 120.55 mm)/2 = 114.40
mm
b. Measure the distances of 3 different
sections of the cam chain, and then
calculate the average chain length.
Example:
(mm)
Checking the cam chain tensioner
1. Measure:
• Wear depth
Above specification → Replace.
TIP:
Measure the wear depth “a” on the guide sur-
face of the cam chain tensioner.
Limit
114.85 mm (4.5216 in)
[1][1]
[5][5]
[4][4]
[6][6]
[3][3]
[2][2]
[4][4]
[3][3]
[5][5]
[2][2]
[1][1]
[1][1]
[5][5]
[4][4]
[6][6]
[3][3]
[2][2]
[4][4]
[3][3]
[5][5]
[2][2]
[1][1]
[1][1]
[5][5]
[4][4]
[6][6]
[3][3]
[2][2]
[4][4]
[3][3]
[5][5]
[2][2]
[1][1]
[1][1]
[5][5]
[4][4]
[6][6]
[3][3]
[2][2]
[4][4]
[3][3]
[5][5]
[2][2]
[1][1]
3
2 3 2
1
1
PORT STBD
Chain length of
measured section 1
114.40
Chain length of
measured section 2
114.50
Chain length of
measured section 3
114.45
Average 114.45
13
.....
11
212
a
b