Yamaha Fz1n Service Manual

							
CAMSHAFTS
5-13
EAS23850
CHECKING THE CAMSHAFTS
1. Check: Camshaft lobes
Blue discoloration/pitting/scratches  → 
Replace the camshaft.
2. Measure:
 Camshaft lobe dimensions “a” and “b”Out of specification  → Replace the cam-
shaft. 3. Measure:
 Camshaft runoutOut of specification  → Replace.
4. Measure:  Camshaft-journal-to-camshaft-cap clear-
ance
Out of specification  → Measure the cam-
shaft journal diameter.
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a. Install the camshaft into the cylinder head 
(without the dowel pins and camshaft 
caps).
b. Position strip of Plastigauge® “1” onto the  camshaft journal as shown.
c. Install the dowel pins and camshaft caps.
NOTE:
 Tighten the camshaft cap bolts in stages and 
in a crisscross pattern, working from the 
inner caps out.
 Do not turn the camshaft when measuring 
the camshaft journal-to-camshaft cap clear-
ance with the Plastigauge®.
d. Remove the camshaft caps and then mea- sure the width of the Plastigauge® “2”.
Camshaft lobe dimension limitIntake camshaft “a”32.50–32.60 mm
(1.280–1.284 in)
Limit
32.40 mm (1.276 in)
Intake camshaft “b”
24.95–25.05 mm
(0.982–0.986 in)
Limit
24.85 mm (0.978 in)
Exhaust camshaft “a” 30.70–30.80 mm
(1.209–1.213 in)
Limit
30.60 mm (1.205 in)
Exhaust camshaft “b”
22.95–23.05 mm
(0.904–0.908 in)
Limit
22.85 mm (0.900 in)
Camshaft runout limit0.03 mm (0.0012 in)
Camshaft-journal-to-camshaft-
cap-clearance0.028–0.062 mm
(0.0011–0.0024 in)
Camshaft cap bolt10 Nm (1.0 m·kg, 7.2 ft·lb) 
						

							
CAMSHAFTS
5-14
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5. Measure: Camshaft journal diameter “a”
Out of specification  → Replace the cam-
shaft.
Within specification  → Replace the cylinder 
head and the camshaft caps as a set.
EAS23870
CHECKING THE TIMING CHAIN AND CAM-
SHAFT SPROCKET
1. Check:  Timing chain “1”Damage/stiffness  → Replace the timing 
chain and camshaft and camshaft sprocket 
as a set. 2. Check:
 Camshaft sprocketMore than 1/4 tooth wear “a”  → Replace 
the camshaft sprockets and the timing 
chain as a set.
EAS23950
CHECKING THE TIMING CHAIN GUIDES
The following procedure applies to all of the 
camshaft sprockets and timing chain guides.
1. Check:  Timing chain guide (exhaust side) “1”
 Timing chain guide (intake side) “2”
 Timing chain guide (top side) “3”Damage/wear  → Replace the defective 
part(s).
EAS23960
CHECKING THE TIMING CHAIN TEN-
SIONER
1. Remove:  Timing chain tensioner housing “1”
 Timing chain tensioner rod “2”
 Timing chain tensioner spring “3”
Camshaft journal diameter22.459–22.472 mm
(0.8842–0.8847 in)
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Camshaft sprocket 
						

							
CAMSHAFTS
5-15
NOTE:
Squeeze the timing chain tensioner clip, and 
then remove the timing chain tensioner spring 
and timing chain tensioner rod.
2. Check: Timing chain tensioner housing
 Timing chain tensioner rod
 Timing chain tensioner springDamage/wear  → Replace.
3. Install:  Timing chain tensioner spring
 Timing chain tensioner rod “1”
NOTE:
Prior to installing the timing chain tensioner  
rod, drain the engine oil from the timing chain 
tensioner housing.
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a. Install the timing chain tensioner spring and  timing chain tensioner rod “1”. b. Squeeze the timing chain tensioner clip “2” 
and push the timing chain tensioner rod “3”.
NOTE:
When the timing chain tensioner rod “3” is 
pushed while holding the grip of the timing 
chain tensioner clip “2”, make sure not to 
release the timing chai n tensioner rod “3” 
before releasing the timing chain tensioner clip 
“2”. (Otherwise, the timing chain tensioner rod 
“3” may run off.)
c. Hook the clip “4” to the timing chain ten- sioner rod “3”.
NOTE:
Hook the timing chain t ensioner rod pin “5” to 
the center of the clip “4”. After the installation, 
check that the clip “4” can come off by its own 
weight by pushing the timing chain tensioner 
rod “3” at the position of installation.
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CAMSHAFTS
5-16
EAS24000
INSTALLING THE CAMSHAFTS
1. Align: “T” mark “a” on the pickup rotor
(with the crankcase mating surface “b”)
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a. Turn the crankshaft clockwise.
b. When position #1 is at TDC, align the “T”  mark “a” with the crankcase mating surface 
“b”.
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2. Install: Intake camshaft sprocket “1”
 Exhaust camshaft sprocket “2”(with the camshaft sprockets temporarily 
tightened)
NOTE:
Install the camshaft sprocke ts as a illustration.
3. Install:  Exhaust camshaft “1”
 Intake camshafts “2”(with the camshaft sprockets temporarily 
tightened)
NOTE:
Make sure the punch mark “a” on each cam-
shaft faces up. 4. Install:
 Dowel pins
 Intake camshaft caps
 Exhaust camshaft caps
NOTE:
 Make sure each camshaft cap is installed in its original place. Refer to the identification 
marks as follows:
“I”: Intake side camshaft cap mark
“E”: Exhaust side camshaft cap mark
“L”: Left side camshaft cap mark
“R”: Right side camshaft cap mark
 Make sure the arrow mark “a” on each cam- shaft points towards the right side of the 
engine.
5. Install:  Camshaft cap bolts
NOTE:
Tighten the camshaft cap bolts in stages and 
in a crisscross pattern, working from the inner 
caps out.
CAUTION:
EC2D1001
 Lubricate the camshaft cap bolts with the engine oil.
Camshaft cap bolt10 Nm (1.0 m·kg, 7.2 ft·lb) 
						

							
CAMSHAFTS
5-17
 The camshaft cap bolts must be tightened evenly or damage to the cylinder head, 
camshaft caps, and camshafts will result.
 Do not turn the crankshaft when installing  the camshaft to avoid damage or 
improper valve timing.
6. Tighten:  Camshaft sprocket bolts “1”
CAUTION:
EC2D1002
Be sure to tighten the camshaft sprocket 
bolts to the specified torque to avoid the 
possibility of the bolts coming loose and 
damaging the engine.
7. Align: Camshaft punch mark “a”
Align the camshaft punch mark “a” and the 
camshaft cap arrow mark “b”.
8. Install: Gasket   Timing chain tensioner “1”
 Timing chain tensioner bolts “2”
CAUTION:
EC2D1003
The arrow mark “a” on the timing chain ten-
sioner should face up.
WARNING
EW2D1006
Always use a new gasket.
9. Turn:
 Crankshaft
(several turns clockwise)
10. Check: “T” mark “a”Make sure the “T” mark on the pickup rotor 
is aligned with the crankcase mating sur-
face “b”.
 Camshaft punch mark “c”
Make sure the punch mark “c” on the cam-
shaft is aligned with the camshaft cap 
arrow mark “d”.
Out of alignment  → Adjust.
Refer to the installation steps above.
Camshaft sprocket bolt 24 Nm (2.4 m·kg, 17 ft·lb)
Camshaft wrench90890-04143
Camshaft wrench90890-04143
Timing chain tensioner bolt10 Nm (1.0 m·kg, 7.2 ft·lb) 
						

							
CAMSHAFTS
5-18
11. Measure: Valve clearanceOut of specification  → Adjust.
Refer to ADJUSTING THE VALVE 
CLEARANCE on page 3-4.
12. Install:  Pickup coil rotor cover
CRANKSHAFT POSITION SENSOR on 
page 5-38. 
						

							
CYLINDER HEAD
5-19
EAS24100
CYLINDER HEAD
Removing the cylinder head
Order Job/Parts to remove Q’ty RemarksEngine Refer to ENGINE REMOVAL on page 5-2.
Intake camshaft Refer to CAMSHAFTS on page 5-10.
Exhaust camshaft Refer to CAMSHAFTS on page 5-10.
1 Cylinder head 1
2 Cylinder head gasket 1
3 Dowel pin 2
4 Coolant pipe 1
5O-ring 1
6 Thermo wax outlet hose 1
7 Right front engine mounting bolt 2 1 For assembly, reverse the removal 
procedure. 
						

							
CYLINDER HEAD
5-20
EAS24120
REMOVING THE CYLINDER HEAD
1. Remove: Intake camshaft
 Exhaust camshaft
Refer to REMOVING THE CAMSHAFTS 
on page 5-12.
2. Remove:  Cylinder head nuts
 Cylinder head bolts
NOTE:
 Loosen the nuts in the proper sequence as shown.
 Loosen each nut 1/2 of a turn at a time. After  all of the nuts are fully loosened, remove 
them.
EAS24160
CHECKING THE CYLINDER HEAD
1. Eliminate:
 Combustion chamber carbon deposits(with a rounded scraper)
NOTE:
Do not use a sharp instrument to avoid damag-
ing or scratching:
 Spark plug bore threads
 Valve seats
2. Check:  Cylinder head
Damage/scratches  → Replace.
 Cylinder head water jacket Mineral deposits/rust  → Eliminate.
3. Measure:  Cylinder head warpageOut of specification  → Resurface the cylin-
der head.
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a. Place a straightedge “1” and a thickness  gauge “2” across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin- der head as follows.
d. Place a 400–600 grit wet sandpaper on the  surface plate and resurface the cylinder 
head using a figure-eight sanding pattern.
NOTE:
To ensure an even surface, rotate the cylinder 
head several times.
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EAS24240
INSTALLING THE CYLINDER HEAD
1. Check: Cylinder head bolts “1”
NOTE:
Retighten the cylinder head bolts to specifica-
tion, before installing the cylinder head.
2. Install:
Maximum cylinder head 
warpage0.10 mm (0.0039 in)
Cylinder head bolt8 Nm (0.8 m·kg, 5.8 ft·lb) 
						

							
CYLINDER HEAD
5-21
Gasket “1” 
 Dowel pins
3. Install:  Cylinder head
NOTE:
Pass the timing chain th rough the timing chain 
cavity.
4. Tighten:
 Cylinder head nuts “1” – “10”
 Cylinder head bolts “11” “12”
NOTE:
 First, tighten the nuts “1” – “10” to approxi-mately 19 Nm (1.9 m·kg, 14 ft·lb) with a 
torque wrench, and then tighten the 67 Nm 
(6.7 m·kg, 48 ft·lb).
 Lubricate the cylinder head nuts with engine 
oil.
 Tighten the cylinder head nuts in the proper  tightening sequence as shown and torque 
them in two stages. 5. Install:
 Exhaust camshaft
 Intake camshaft
Refer to INSTALLING THE CAMSHAFTS 
on page 5-16.
Cylinder head nut (1st)19 Nm (1.9 m·kg, 14 ft·lb)
Cylinder head nut (2nd)67 Nm (6.7 m·kg, 48 ft·lb)
Cylinder head bolt
12 Nm (1.2 m·kg, 8.7 ft·lb) 
						

							
VALVES AND VALVE SPRINGS
5-22
EAS24270
VALVES AND VALVE SPRINGS
Removing the valves and valve springs
Order Job/Parts to remove Q’ty RemarksCylinder head Refer to CYLINDER HEAD on  page 5-19.
1 Intake valve lifter 12
2 Intake valve pad 12
3 Intake valve cotter 24
4 Intake valve upper spring seat 12
5 Intake valve spring 12
6 Intake valve stem seal 12
7 Intake valve lower spring seat 12
8 Intake valve 12
9 Intake valve guide 12
10 Exhaust valve lifter 8
11 Exhaust valve pad 8
12 Exhaust valve cotter 16
13 Exhaust valve upper spring seat 8
14 Exhaust valve spring 8
15 Exhaust valve stem seal 8