Yamaha Fz1n Service Manual

							
CRANKSHAFT
5-83
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2. Select: Crankshaft journal bearings (J1–J5)
NOTE:
 The numbers “A” stamped into the crank-shaft web and the numbers “1” stamped into 
the lower crankcase are used to determine 
the replacement crankshaft journal bearing 
sizes.
 “J1–J5” refer to the bearings shown in the  crankshaft illustration.
 If “J1–J5” are the same, use the same size 
for all of the bearings.
 If the size is the same for all “J
1 to J5” one 
digit for that size is indicated. (Crankcase 
side only)
For example, if the crankcase “J
1” and 
crankshaft web “J
1” numbers are “6” and 
“2” respectively, then the bearing size  for 
“J
1” is:
ET2D1021
INSTALLING THE CRANKSHAFT
1. Install:  Crankshaft journal upper bearings “1”(into the upper crankcase)
2. Lubricate:  Crankshaft journal upper bearings(with the recommended lubricant)
“J
1” (crankcase)  – “J1”
(crankshaft web) – 1 =
6 – 2 – 1 = 3 (brown)
CRANKSHAFT JOURNAL BEARING  COLOR CODE
0White
1Blue
2Black
3Brown
4Green
Recommended lubricant Engine oil 
						

							
CRANKSHAFT
5-84
NOTE:
 Align the projections “a” on the crankshaft journal upper bearings with the notches “b” in 
the upper crankcase.
 Be sure to install each crankshaft journal 
upper bearing in its original place.
3. Install:  Crankshaft
4. Install:  Crankcase (lower)Refer to CRANKCASE on page 5-66.
5. Install: Pin
 Pickup rotor “1”
 Drive sprocket “2”
Drive sprocket bolt60 Nm (6.0 m·kg, 43 ft·lb) 
						

							
TRANSMISSION
5-85
EAS26240
TRANSMISSION
Removing the transmission, shift drum assembly, and shift forks
Order Job/Parts to remove Q’ty RemarksCrankcase lower Separate.
Refer to CRANKCASE on page 5-
66
.
1 Drive axle assembly 1
2 Circlip 1
3 Oil seal 1
4 Bearing 1
5 Washer 1
6 Shift fork guide bar retainer 2
7Spring 2
8 Shift fork guide bar 2
9 Shift fork “L” 1
10 Shift fork “R” 1
11 Shift drum assembly 1
12 Shift fork “C” 1
13 Main axle retainer 1 
						

							
TRANSMISSION
5-86
14 Main axle assembly 1
15 Oil pipe 1
16 O-ring 2
17 Oil baffle plate 1For installation, reverse the removal 
procedure.
Removing the transmission, shift drum assembly, and shift forks
Order Job/Parts to remove Q’ty Remarks 
						

							
TRANSMISSION
5-87
Disassembling the main axle assenbly
Order Job/Parts to remove Q’ty Remarks1 2nd pinion gear 1
2 Toothed lock washer 1
3 Toothed lock washer retainer 1
4 6th pinion gear 1
5Collar 1
6 Washer 1
7 Circlip 1
8 3rd pinion gear 1
9 Circlip 1
10 Washer 1
11 5th pinion gear 1
12 Collar 1
13 Main axle 1
14 Bearing housing 1
15 Bearing 1 For assembly, reverse the disassem-
bly procedure. 
						

							
TRANSMISSION
5-88
Disassembling the drive axle assenbly
Order Job/Parts to remove Q’ty Remarks1 Washer 1
2 1st wheel gear 1
3Collar 1
4 5th wheel gear 1
5 Circlip 1
6 Washer 1
7 3rd wheel gear 1
8Collar 1
9 Toothed lock washer 1
10 Toothed lock washer retainer 1
11 4th wheel gear 1
12 Collar 1
13 Washer 1
14 Circlip 1
15 6th wheel gear 1
16 Circlip 1
17 Washer 1
18 Collar 1
19 2nd wheel gear 1
20 Collar 1 
						

							
TRANSMISSION
5-89
21 Oil seal 1
22 Bearing 1
23 Drive axle 1For assembly, reverse the disassem-
bly procedure.
Disassembling the drive axle assenbly
Order Job/Parts to remove Q’ty Remarks 
						

							
TRANSMISSION
5-90
EAS26250
REMOVING THE TRANSMISSION
1. Remove: Drive axle asseembly “1”
 Shift drum retainers “2”
 Shift fork guide bars
 Shift fork “L” and “R”
 Shift drum assembly
 Shift fork “C”
2. Remove:  Bearing housing “1”
 Main axle assembly “2”
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a. Insert two bolts “3” of the proper size, as  shown in the illustration, into the main axle 
assembly bearing housing.
b. Tighten the bolts until they contact the  crankcase surface.
c. Continue tightening the bolts until the main  axle assembly comes free from the upper 
crankcase.
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3. Remove: Oil pipe “1”
 Bearing “2”
EAS26260
CHECKING THE SHIFT FORKS
The following procedure applies to all of the 
shift forks.
1. Check: Shift fork cam follower “1”
 Shift fork pawl “2”Bends/damage/scoring/wear  → Replace 
the shift fork.
2. Check:  Shift fork guide barRoll the shift fork guide bar on a flat sur-
face.
Bends  → Replace.
WARNING
EWA12840
Do not attempt to straighten a bent shift 
fork guide bar. 
						

							
TRANSMISSION
5-91
3. Check: Shift fork movement(along the shift fork guide bar)
Rough movement  → Replace the shift 
forks and shift fork guide bar as a set.
EAS26270
CHECKING THE SHIFT DRUM ASSEMBLY
1. Check:  Shift drum grooves “1”
Damage/scratches/wear  → Replace the 
shift drum assembly.
 Shift drum segment “2” Damage/wear  → Replace the shift drum 
assembly.
 Shift drum bearing “3” Damage/pitting  → Replace the shift drum 
assembly.
EAS26280
CHECKING THE TRANSMISSION
1. Measure:  Main axle runout
(with a centering device and dial gauge “1”) Out of specification 
→ Replace the main 
axle.
2. Measure:  Drive axle runout(with a centering device and dial gauge “1”)
Out of specification  → Replace the drive 
axle.
3. Check:  Transmission gears
Blue discoloration/pitting/wear  → Replace 
the defective gear(s).
 Transmission gear dogs
Cracks/damage/rounded edges  → Replace 
the defective gear(s).
Main axle runout limit 0.08 mm (0.0032 in)
Drive axle runout limit0.08 mm (0.0032 in) 
						

							
TRANSMISSION
5-92
ET2D1022
INSTALLING THE TRANSMISSION
1. Install: Bearing “1”
NOTE:
Make the seal side of bearing face to the out-
side and install it close to the right end face of 
the crankcase.
 Oil pipe “2”
2. Install:  Main axle assembly “1”
 Bearing housing “2”
 Shift fork “C”
 Shift drum assembly
 Shift fork guide bar
 Shift fork guide bar retainer
NOTE:
 The embossed marks on the shift forks should face towards the right side of the 
engine and be in the following sequence: “R”, 
“C”, “L”.
 Carefully position the shift forks so that they 
are installed correctly into  the transmission 
gears.
 Install shift fork “C” into  the groove in the 3rd 
and 4th pinion gear on the main axle.
3. Install: Shift fork “L” “1” and “R” “2” 
 Drive axle assembly “3”
 Shift fork guide bar
 Shift fork guide bar retainer “4”
NOTE:
 Install shift fork “L” into the groove in the 6th wheel gear and shift fork “R” into the groove 
in the 5th wheel gear on the drive axle.
 Make sure that the drive axle bearing circlip 
“a” is inserted into the grooves in the upper 
crankcase.Bearing housing bolt12 Nm (1.2 m·kg, 8.7 ft·lb)
LOCTITE®
Shift fork guide bar retainer bolt
10 Nm (1.0 m·kg, 7.2 ft·lb)
LOCTITE®
Shift fork guide bar retainer bolt10 Nm (1.0 m·kg, 7.2 ft·lb)
LOCTITE®