Yamaha Fz6 N Service Manual

							
CAMSHAFTS
5-10
EAS23810
REMOVING THE CAMSHAFTS
1. Remove: Pickup rotor cover
Refer to PICKUP ROTOR on page 5-33.
2. 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 piston #1 is at TDC on the compres- sion stroke, align the “T” mark “a” on the 
pickup rotor with the crankcase mating sur-
face “b”.
NOTE:
TDC on the compression stroke can be found 
when the camshaft lobes are turned away from 
each other.
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3. Loosen: Camshaft sprocket bolts “1”
4. Loosen:  Timing chain tensioner cap bolt “1”
5. Remove:
 Timing chain tensioner “2”
Gasket 6. Remove:
 Timing chain guide (exhaust side)
 Camshaft caps “1”
 Dowel pins
CAUTION:
ECA13720
To prevent damage to the cylinder head, 
camshafts or camshaft caps, loosen the 
camshaft cap bolts in stages and in a criss-
cross pattern, working from the outside in.
7. Remove: Intake camshaft “1”
 Exhaust camshaft “2”
NOTE:
To prevent the timing chain from falling into the 
crankcase, fasten it with a wire “a”. 
						

							
CAMSHAFTS
5-11
8. Remove: Camshaft sprockets
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 runout Out 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.
Camshaft lobe dimension limit
Intake A32.450–32.550 mm (1.2776–
1.2815 in)
Limit 32.400 mm (1.2756 in)
Intake B
24.950–25.050 mm (0.9823–
0.9862 in)
Limit
24.900 mm (0.9803 in)
Exhaust A 32.450–32.550 mm (1.2776–
1.2815 in)
Limit 32.400 mm (1.2756 in)
Exhaust B 24.950–25.050 mm (0.9823–
0.9862 in)
Limit 24.900 mm (0.9803 in)Camshaft runout limit0.060 mm (0.0024 in)
Camshaft-journal-to-camshaft-
cap clearance0.028–0.062 mm (0.0011–
0.0024 in)
Limit 0.080 mm (0.0032 in) 
						

							
CAMSHAFTS
5-12
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”.
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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 sprocket as a set.
2. Check:  Camshaft sprocket More than 1/4 tooth wear “a”  → Replace 
the camshaft sprocket and the timing chain 
as a set.
EAS23950
CHECKING THE TIMING CHAIN GUIDES
1. Check:  Timing chain guide (exhaust side) “1”
 Timing chain guide (intake side) “2”
 Timing chain guide (top side) “3”
Camshaft cap bolt
10 Nm (1.0 m·kg, 7.2 ft·lb)
Camshaft journal diameter22.967–22.980 mm (0.9042–
0.9047 in)a. 1/4 tooth
b. Correct
1. Timing chain roller
2. Camshaft sprocket 
						

							
CAMSHAFTS
5-13
Damage/wear → Replace the defective 
part(s).
EAS23970
CHECKING THE TIMING CHAIN TEN-
SIONER
1. Check:  Timing chain tensioner
Cracks/damage  → Replace.
2. Check:  One-way cam
Rough movement  → Replace the timing 
chain tensioner assembly.
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a. Lightly press the timing chain tensioner rod  into the timing chain tensioner housing by 
hand.
NOTE:
While pressing the timing chain tensioner rod, 
wind it clockwise with a thin screwdriver “1” 
until it stops.
b. Remove the screwdriver and slowly release the timing chain tensioner rod.
c. Make sure that the timing chain tensioner 
rod comes out of the timing chain tensioner 
housing smoothly. If there is rough move-
ment, replace the timing chain tensioner.
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3. Check: Timing chain tensioner cap bolt
 Aluminum washer 
Gasket 
Damage/wear  → Replace the defective 
part(s).
EAS24010
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 piston #1 is at TDC, align the “T”  mark “a” with the crankcase mating surface 
“b”.
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2. Install:
 Exhaust camshaft “1”
 Intake camshaft “2” (with the camshaft sprockets temporarily 
tightened)
NOTE:
Make sure the match mark “a” on the camshaft 
sprockets is aligned with the cylinder head 
edge “b”.
New
New 
						

							
CAMSHAFTS
5-14
3. 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:
“I1”, “I2”: Intake side camshaft cap mark
“E1”, “E2”: Exhaust side camshaft cap mark
 Make sure the arrow mark “a” on each cam- shaft points towards the right side of the 
engine.
4. Install:  Camshaft cap bolts
NOTE:
Tighten the camshaft cap bolts in stages and 
in a crisscross pattern,  working from the inner 
caps out.
CAUTION:
ECA4S81016
 Lubricate the camshaft cap bolts with the 
engine oil.
 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.
5. Install:  Timing chain guide (exhaust side)
NOTE:
When installing the timing chain guide, be sure 
to keep the timing chain as tight as possible on 
the exhaust side.
6. Install: Timing chain tensioner
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a. While lightly pressing  the timing chain ten-
sioner rod by hand, turn the tensioner rod 
fully clockwise with a thin screwdriver “1”.
b. With the timing chain tensioner rod turned 
all the way into the timing chain tensioner 
housing (with the thin screwdriver still 
installed), install the gasket and the timing 
chain tensioner “2” onto the cylinder block.
WARNING
EWA4S81008
Always use a new gasket.
c. Tighten the timing chain tensioner bolts “3” to the specified torque.
d. Remove the screwdriver, make sure the  timing chain tensioner  rod releases, and 
then tighten the cap bolt to the specified 
torque.
Camshaft cap bolt 10 Nm (1.0 m·kg, 7.2 ft·lb)
Timing chain tensioner bolt12 Nm (1.2 m·kg, 8.7 ft·lb)
Timing chain tensioner cap bolt7 Nm (0.7 m·kg, 5.1 ft·lb) 
						

							
CAMSHAFTS
5-15
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7. Turn: Crankshaft
(several full turns clockwise)
8. Check: “T” mark “a”
Make sure the “T” mark on the pickup rotor 
is aligned with the crankcase mating sure 
face “b”.
 Camshaft sprocket  match mark “c”
Make sure the match marks on the cam-
shaft sprockets are aligned with the edge of 
the cylinder head “d”.
Out of alignment  → Adjust.
Refer to the installation steps above.
9. Tighten:
 Camshaft sprocket bolts “1”
CAUTION:
ECA4S81017
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. 10. Measure:
 Valve clearance Out of specification  → Adjust.
Refer to ADJUSTING THE VALVE 
CLEARANCE on page 3-4.
Camshaft sprocket bolts 20 Nm (2.0 m·kg, 1.5 ft·lb) 
						

							
CYLINDER HEAD
5-16
EAS24100
CYLINDER HEAD
Removing the cylinder head
Order Job/Parts to remove Q’ty RemarksIntake camshaft Refer to CAMSHAFTS on page 5-8.
Exhaust camshaft Refer to CAMSHAFTS on page 5-8.
1 Cylinder head 1
2 Cylinder head gasket 1
3Dowel pin 2 For installation, reverse the removal proce-
dure. 
						

							
CYLINDER HEAD
5-17
EAS24120
REMOVING THE CYLINDER HEAD
1. Remove: Cylinder head bolts
NOTE:
 Loosen the bolts in the proper sequence as 
shown.
 Loosen each bolts 1/2 of a turn at a time.  After all of the bolts 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 warpage Out 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. Install:
 Cylinder head gasket “1” 
 Dowel pins “2”
2. Install:  Cylinder head
Warpage limit 0.05 mm (0.0020 in)
New 
						

							
CYLINDER HEAD
5-18
NOTE:
Pass the timing chain through the timing chain 
cavity.
3. Tighten: Cylinder head bolts “1” – “10”
 Cylinder head bolts “11” “12”
NOTE:
 Lubricate the cylinder head bolts with engine 
oil.
 Tighten the cylinder head bolts in the proper  tightening sequence as shown and torque 
them in two stages.
 First, tighten the bolts “1” – “10” to approxi- mately 19 Nm (1.9 m·kg, 14 ft·lb) with a 
torque wrench and then tighten the 50 Nm 
(5.0 m·kg, 36 ft·lb).
4. Install:  Exhaust camshaft
 Intake camshaft
Refer to INSTALLING THE CAMSHAFTS 
on page 5-13.
Cylinder head bolt (1st)19 Nm (1.9 m·kg, 14 ft·lb)
Cylinder head bolt (2nd)50 Nm (5.0 m·kg, 36 ft·lb)
Cylinder head bolt12 Nm (1.2 m·kg, 8.7 ft·lb) 
						

							
VALVES AND VALVE SPRINGS
5-19
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 5-16.
1 Intake valve lifter 8
2 Intake valve pad 8
3 Intake valve cotter 16
4 Intake valve upper spring seat 8
5 Intake valve spring outer 8
6 Intake valve spring inner 8
7 Intake valve stem seal 8
8 Intake valve lower spring seat 8
9 Intake valve 8
10 Intake valve guide 8
11 Exhaust valve lifter 8
12 Exhaust valve pad 8
13 Exhaust valve cotter 16
14 Exhaust valve upper spring seat 8
15 Exhaust valve spring 8
16 Exhaust valve stem seal 8
17 Exhaust valve lower spring seat 8
18 Exhaust valve 8
19 Exhaust valve guide 8