Yamaha F2 5 Service Manual

69M3E115-20
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7. If the valve seat contact area is too nar-
row and situated near the top edge of the
valve face, use a 30° cutter to cut the top
edge of the valve seat. If necessary, use
a 45° cutter to center the area and set its
width.
bPrevious contact width
8. If the valve seat contact area is too nar-
row and situated near the bottom edge of
the valve face, use a 60° cutter to cut the
bottom edge of the valve seat. If neces-
sary, use a 45° cutter to center the area
and set its...

POWRPower unit
5-2169M3E11
Installing the valves
1. Install the new stem seal 1
 to the valve
guide.
2. Install the valve 2
, valve spring 3
, and
valve spring retainer 4
 in the sequence
shown, and then attach the special ser-
vice tool.
NOTE:
The valve spring can be installed in any
direction.3. Compress the valve spring, and then
install the valve cotter 7
 using a thin
screwdriver with a small amount of
grease applied to it.
4. Lightly tap the valve spring retainer with
a plastic hammer to set the...

69M3E115-22
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Cylinder block5
No. Part name Q’ty Remarks
1 Cylinder body 1
2 Crankcase 1
3 Crankshaft 1
4Camshaft 1
5 Connecting rod assembly 1
6Piston 1
7 Oil ring 1
8 Second ring 1
9 Top ring 1
10 Piston pin 1
11 Gasket 1
Not reusable
12 Oil splasher gear 1
13 Oil seal housing 1
14 Oil seal 1
Not reusable
15 Ball bearing 1Not reusable
16 Oil seal 1Not reusable
17 Oil seal 2Not reusable
Cylinder head / Cylinder block 

POWRPower unit
5-2369M3E11
5
No. Part name Q’ty Remarks
18 Clamp 1
19 Washer 1
20 Dowel 2
21 Drain bolt 1 M8 
× 20 mm
22 Bolt 8 M6 
× 45 mm
23 Bolt 1 M8 
× 14 mm
24 Bolt 1 M8 
× 20 mm
25 Bolt 2 M6 
× 29 mm
26 Bolt 1 M6 
× 12 mm
27 Piston pin clip 2
Not reusable
28 Metal gasket 1Not reusable
29 Metal gasket 1Not reusable
30 O-ring 1Not reusable
31 Valve lifter 2
32 Hose 1 

69M3E115-24
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Disassembling the cylinder body
1. Remove the crankcase cover bolts in the
sequence shown.
2. Remove the crankcase.
NOTE:
Insert a flat head screwdriver between the
tab of the crankcase and the tab of the cylin-
der block to pry open the two parts.
3. Remove the camshaft 1
, and then
remove the valve lifters 2
.4. Remove the connecting rod bolts and the
connecting rod cap, and then remove the
connecting rod and piston assembly.
5. Remove the clips 3
 with pliers, and then...

POWRPower unit
5-2569M3E11
Checking the cylinder bore
1. Measure the cylinder bore (D1, D2, D3,
D
4, D5, D6) at measuring points a
, b
,
and c
, and in direction d
 (D
1, D3, D5),
which is parallel to the crankshaft, and
direction e
 (D
2, D4, D6), which is at a
right angle to the crankshaft.
2. Calculate the taper limit. Replace or
rebore the cylinder block if out of specifi-
cation.
3. Calculate the out-of-round limit. Replace
or rebore the cylinder block if out of spec-
ification.
Checking the piston...

69M3E115-26
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Checking the piston ring grooves
1. Measure the piston ring grooves.
Replace the piston if out of specification.
Checking the piston ring side 
clearance
1. Measure the piston ring side clearance.
Replace the piston and piston rings as a
set if out of specification.
Checking the piston pin boss bore
1. Measure the piston pin boss bore.
Replace the piston if out of specification.
Piston ring end gap d
:
Top ring:
0.15–0.30 mm 
(0.0059–0.0118 in)
Second ring:
0.30–0.45 mm...

POWRPower unit
5-2769M3E11
Checking the piston pin
1. Measure the piston pin diameter.
Replace if out of specification.
Checking the connecting rod small 
end inside diameter
1. Measure the connecting rod small end
inside diameter a
. Replace the connect-
ing rod if out of specification.
Checking the connecting rod big end 
side clearance
1. Measure the connecting rod big end side
clearance a
. Replace the connecting
rod or crankshaft, or both if out of specifi-
cation.
Checking the crankshaft
1. Check...

69M3E115-28
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3. Measure the crankshaft runout. Replace
the crankshaft if out of specification.
Checking the crankpin oil clearance
1. Clean the connecting rod.
2. Put a piece of Plastigauge
® (PG-1) onto
the crankpin, parallel to the crankshaft.
NOTE:
Be sure not to put the Plastigauge (PG-1)
over the oil hole in the crankpin of the crank-
shaft.
3. Install the connecting rod to the crankpin
1
.
NOTE:
Align the marks a
 on the connecting rod cap
and connecting rod.
Crankpin diameter a
:...

POWRPower unit
5-2969M3E11
4. Tighten the connecting rod bolts 2
 to the
specified torques in two stages.
NOTE:
Reuse the removed connecting rod bolts
when checking the oil clearance.
Do not turn the connecting rod until the
crankpin oil clearance measurement has
been completed.
5. Remove the connecting rod cap and
measure the width of the compressed
Plastigauge (PG-1) on the crankpin.
Replace the connecting rod assembly or
crankshaft if out of specification.
Checking the camshaft
1. Check the teeth of...