Yamaha EF1000 Service Manual

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PISTON, CAMSHAFT, CRANKCASE,  CRANKSHAFT ENG 8 
a 
A 
B 
c 
3-14 
2. Inspect: 
•Camshaft CD 
•Decompressor ell 
•Valve lifter@ 
Damage/Wear---+Replace. 
3. Measure: 
•Camshaft diameter 
Out of specification--+Replace. 
Camshaft diameter: 
Standard: 12.0 mm (0.472 in) 
Limit: 11.9 mm (0.468 in) 
CRANKCASE  INSPECTION 
1. Inspect: 
•Cylinder walls 
Vertical scratches---+Rebore or replace 
cylinder. 
2. Measure: 
•Cylinder inside diameter D 
NOTE: ---------------------------
Obtain measurements at...

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PISTON, CAMSHAFT, CRANKCASE, CRANKSHAFT ENG B 
3-15 
3. Inspect: 
•Crankcase 
Damage--+Replace. 
•Bearing 
Roughness--+Replace bearing. 
PISTON, PISTON PIN AND PISTON  RING 
INSPECTION 
1. Measure: 
•Piston skirt diameter P 
@=10 mm (0.4  in) from the piston bottom edge. 
Piston size P: 
Standard: 50.0 mm (1.969  in) 
Limit: 49.93 mm (1.966 in) 
2. Measure: 
•Piston clearance 
Piston clearance= 
Cylinder 
inside diameter  D ­
Piston skirt diameter  P  
Out of specification--+Rebore cylinder...

PISTON, CAMSHAFT, CRANKCASE,  CRANKSHAFT ENG B 
3-16 
4. Measure: 
•Piston ring end gap 
Use a Thickness  gauge. 
Out of specification-+Replace. 
NOTE: ________________________ __ 
You cannot measure end gap on expander 
spacer of oil control ring. If control ring rails 
show excessive gap, replace all three rings. 
Piston ring end gap: 
0.1-0.25 mm (0.004-0.01 in) 
Piston  ring end gap limit: 
0.9 mm (0.0354 in) 
5. Measure: 
•Piston ring side clearance 
Use  a Thickness  gauge. 
Out of...

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PISTON, CAMSHAFT, CRANKCASE,  CRANKSHAFT ENG B 
3~ 
3-17 
2. Measure: 
•Crankpin outside diameter 
Use a micrometer. 
Out of specification-+Replace. 
Crankpin outside diameter: 
22.0 mm (0.87 in) 
Crankpin outside diameter limit: 
21.9 mm (0.86 in) 
3. Measure: 
•Oil clearance 
Use a plastigauge ®. 
Out of specification-+Replace connec­
ting rod. 
Oil clearance: 
0.016-0.034 mm 
(0.0006-0.0013 in) 
Oil clearance limit: 
0.1 mm (0.004 in) 
Oil clearance measuring  steps: 
1. Clean all parts...

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PISTON, CAMSHAFT, CRANKCASE,  CRANKSHAFT ENG 8 
3-18 
CRANKCASE COVER INSPECTION 
1. Inspect: 
•Crankcase cover 
•Bearing 
Damage/Roughness---+Replace. 
PISTON RING AND PISTON  INSTALLATION 
1. Install: 
•Piston rings 
CAUTION: 
• Be sure to install rings so that manufactur­
ers marks 

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PISTON, CAMSHAFT, CRANKCASE, CRANKSHAFT ENG B 
3-19 
Be sure the II V II mark on the piston head 
faces to push rod side. 
CONNECTING ROD INSTALLATION 
1. Install: 
•Connecting rod cap 
CAVrtoN: --------------------Be sure the connecting rod mark 

RECOIL STARTER ENG 
RECOIL STARTER 
I 40 Nm (4.0 m•kg, 29 ft•lb) I 
13 
JOB  INSTRUCTION CHART 
Order Job name/Parts name Qty  Remarks 
Removal of recoil starter Remove the parts in order. 
Body cover/Fuel tank Refer to the BODY COVER and 
FUEL TANK section  in CHAPTER 2. 
1 Bolt 4 
2 
Recoil starter 1 
3 Starter handle 1 
4 
Bolt 1 
5 Drive plate 1 
6 Drive spring 1 
7 Drive pawl 1 
8 Spring 1 
9 Drum sheave  1 
10 Starter spring 1 
11 Spacer  1 
12 Starter rope 1 
13 Nut 1 
14 
Washer 1 
15 Starter...

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RECOIL STARTER ENG 
RECOIL STARTER REMOVAL 
CAUTION: 
Release the spring pre-load before removing 
the sheave drum bolt. Hook the rope into the 
sheave drum slot G) and turn the sheave 
drum assembly clockwise. 
1. Untie: 
•Knot 

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RECOIL STARTER ENG B 
RECOIL STARTER  INSTALLATION 
1. Install: 
•Starter spring CD 
•Sheave drum~ 
CAUTION: 
Engage the spring hook @ with the drum 
slit, then wind the spring counterclockwise 
into the drum from larger to smaller diame­
ter. 
2. Install: 
•Starter rope 
CAUTION: 
Engage the spring hook 

FLYWHEEL ENG 
FLYWHEEL 
3 
7 6~ 
I 4 Nm {0.4 m•kg, 3 ft•lb) 
JOB  INSTRUCTION CHART 
Order Job name/Parts name Qty Remarks 
Removal of 

Flywheel 
Remove the parts in  order. 
Recoil starter  Refer to the RECOIL STARTER 
section. 
1 Nut 1 
2 Washer 1 
3 Starter 1 
4 
Flywheel 1 
5 
Key 1 
6  Screw 1 
7 
Coil assembly 1 
Reverse the removal procedure for 
installation. 
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