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...

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...

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....

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....

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...

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...

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...

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...