Yamaha EF1000A Service Manual

							RECOIL STARTER AND FLYWHEEL ENG 
RECOIL STARTER AND FLYWHEEL 
7 Nm (0.7 m•kg, 5.1 ft-lb) 
JOB  INSTRUCTION CHART 
Order Job name/Parts name Qty Remarks 
Recoil  starter  and flywheel  removal  Remove 
the parts in the order below. 
Fuel tank Refer to MUFFLER PROTECTOR, 
FUEL TANK AND MUFFLER. 
Air filter assembly  Refer to AIR FILTER AND CARBURETOR. 
C.D.I. unit lead Refer to ENGINE OVERHAUL. 
Carburetor  assembly  Refer to AIR FILTER AND CARBURETOR. 
Link  rod 
Control 
box 
Condenser  lead 
1 Recoil starter  assembly 1 
2 Front flame 1 
3 Starter pulley 1 
4 
Flywheel 1 Refer to Rotor disassembly  and 
assembly. 
5 Coil assembly 1 
6 Woodruff key 1 
For installation,  reverse the removal 
procedure. 
3-10  
						

							RECOIL STARTER AND FLYWHEEL ENG 
RECOIL STARTER 
2 
3 
6 
7 
l\17 Nm (0.7 m•kg, 5.1 ft-lb)l 
JOB INSTRUCTION CHART 
Order Job name/Parts name Oty Remarks 
Recoil starter disassembly Disassembly the parts in the order below. 
1 
Starter handle 1 

-
2 Screw 1 
3 Drive plate 1 
4 Clip 1 
5 Drive pawls 2 Refer to Recoil starter assembly. 6 Springs 2 
7 Sheave drum 1 
8 Starter spring 1 
~1·--Be  sure to the starter spring in the drum sheave. -The spring will spread out suddenly when it is 
removed 
from the sheave drum 
9 Starter  case  1 
10 Starter rope 
1 
For 
assembly, reverse the disassembly 
procedure. 
3-11  
						

							RECOIL STARTER AND FLYWHEEL ENG 
3-12 
REMOVAL 
1. Remove: 
• Flywheel G) 
Use  a  General bearing puller. 
INSPECTION 
1. Inspect: 
•Starter rope G) 
Wear/Damge---+Replace. 
2. Inspect: 
•Starter spring@ 
Contamination---+Ciean and apply grease. 
Wear/Damge---+Replace. 
3. Inspect: 
• 
Drive pawl G) 
•Drive plate@ 
Wear/Damge---+Replace. 
ASSEMBLY 
1. Install: 
•Starter spring G) 
to the sheave drum @ 
NOTE=-------------
Mesh the spring hook@ with the drum slit, 
then wind the spring counter clockwise into 
the drum from larger to smaller diameter. 
2. Install:  •Sheave 
drum G) 
•Starter rope@  
						

							RECOIL STARTER AND FLYWHEEL ENG 
3-13 
3. Install: • 
Drive pawl G) 
•Drive pawl spring@ 
4. Install: 
•Drive plate  clip G) 
•Drive plate@ 
5. Install: 
•Screw G) 
I 
Turn the drum sheave  4 turns counter 
clockwise to give spring preload. 
Rotor assembly 
1. Install: 
•Coil assembly G) 
• Wood ruff key @ 
2. Install: 
•Flywheel G) 
NOTE=-------------------------
Aiign the woodruff key with the slit on the 
rotor.  
						

							CRANKCASE COVER AND CAMSHAFT ENG 
CRANKCASE COVER AND CAMSHAFT 
l 
m 
JOB INSTRUCTION CHART 
Order Job name/parts name 
Crankcase  cover and camshaft 
removal 
Engine oil 
Muffler and muffler protector 
Fuel tank and control box 
Air filter assembly and carburetor 
assembly 
Cylinder head 
Recoil starter assembly and rotor 
assembly 
1  Crankcase cover 
2 Gasket  (crankcase  cover) 
3 
Dowel pins 
4 Camshaft 
5 
Valve lifter 
2 
10 Nm (1.0 m•kg, 7.2 ft-lb) 
Oty Remarks 
Remove 
the parts  in the order below. 
Refer to ENGINE  OIL REPLACEMENT in 
chapter  3. 
Refer 
to MUFFLER  PROTECTOR, 
-]FUEL TANK AND MUFFLER. 
-
Refer to AIR FILTER AND CARBURETOR. 
Refer to CYLINDER  HEAD. 
Refer to RECOIL STARTER AND 
FLYWHEEL. 
1 
1  Refer 
to Crankcase cover installation. 
2 
1 
2 Refer to Camshaft installation. 
For installation, reverse the removal 
procedure. 
3-14  
						

							CRANKCASE COVER AND CAMSHAFT ENG 
3-15 
REMOVAL 
1. Remove: 
•Crankcase cover 
INSPECTION 
Camshaft 
1. Inspect: 
•Camshaft CD 
Wear/Damge--+Replace. 
2. Measure: 
•Cam lobes length  ® and @ 
Use  a micro meter. 
Out of specification--+Replace. 
Cam lobe length @: 
Intake:  20.5 ± 0.05 mm 
(0.807 ± 0.002 in) 
Exhaust: 
20.5 ± 0.05 mm 
(0.807 ± 0.002 in) 
Cam 
lobe length @: 
Intake:  16.0 ± 0.05 mm 
(0.63 ± 0.002 in) 
Exhaust: 
16.0 ± 0.05 mm 
(0.63 ± 0.002 in) 
3. Inspect 
•Camshaft gear  teeth 
Wear/Damge--+Replace. 
4. Measure: 
•Camshaft diameter® 
Out of specification--+Replace. 
Camshaft diameter (limit): 
15.95 mm (0.6280 in)  
						

							CRANKCASE COVER AND CAMSHAFT ENG 
1------G) 
3-16 
Valve lifter 
1. Inspect: 
•Valve 
lifter G) 
Wear/Damge-)>Replace. 
Camshaft installation 
1. Install: 
•Camshaft G) 
NOTE:--------------------------
Be sure to align the camshaft gear mark® 
with the crankshaft  gear mark@. 
Crankcase cover 
1. Inspect: 
•Crankcase 
cover 
Wear/Damge-)>Replace. 
•Bearings 
Damage/Roughness-)>Replace. 
Crankcase  cover installation 
1. Install: 
•Dowel pins 
•Gasket (crankcase  cover) 1111 
•Crankcase cover 
I,.,...~....,I-1_0_N_m_(-1.-0-m-·k-g-, -7.-2 -ft-·lb-....,) I 
NOTE:--------------------------
Follow proper tightening sequence.  
						

							PISTON, CONNECTING  ROD, 
CRANKSHAFT AND CRANKCASE ENG 
PISTON, CONNECTING  ROD, CRANKSHAFT AND CRANKCASE 
1 
m 
JOB INSTRUCTION  CHART 
Order Job name/parts name 
Piston, 
connecting rod and 
crankshaft removal 
Rotor assembly 
Camshaft 
1 Connecting rod  cap 
2 Crankshaft assembly 
3 Connecting rod 
4 Piston pin circlip 
5  Piston  pin 
6 Piston 
7 Piston rings 
Oty 
1 
1  -
1 
2  -
1 
1 
3 
3-17 
1 
m 
Remarks 
Remove 
the parts in the order below. 
Refer to RECOIL STARTER AND FLYWHEEL. 
Refer to CRANKCASE  COVER AND 
CAMSHAFT. 
Refer to Connecting rod and  crankshaft 
installation. 
For installation, reverse the removal 
procedure.  
						

							a 
A 
B 
c 
PISTON, CONNECTING  ROD, 
CRANKSHAFT AND CRANKCASE ENG 
3-18 
INSPECTION 
Crankcase (cylinder) 
1. Measure: 
•Cylinder inside diameter 
Use a cylinder gauge. 
Out of specification---+Rebore the 
cylinder, and replace the piston and 
piston rings. 
NOTE=-------------
Take side to side and front to back 
measurements at each of the 3 rotations 
(total of 6 measurements). Then, find the 
average of the measurements. 
D = Maximum A, B, C 
T 
=Maximum A-Minimum C 
2. Inspect: 
•Cylinder wrappage 
Out of specification---+Replace 
Wrappage limit: 
0.05 mm (0.002 in) 
Piston and piston pin 
1. Measure: 
•Piston diameter® 
® = 10 mm (0.3937  in) from the bottom 
edge of the piston. 
Standard piston size: 
50.0 mm (1.968 in) 
Piton wear limit: 
49.93 mm (1.965 in) 
2. Calculate: 
•Piston clearance 
Piston 
clearance = 
Cylinder inside diameter D -
Piston skirt diameter P 
Out of specification---+Rebore the 
cylinder and replace the piston and 
piston rings. 
Piston clearance: 
0.020 ... o.035 mm 
(0.00078 ... o.00137 in)  
						

							PISTON, CONNECTING  ROD, 
CRANKSHAFT AND CRANKCASE ENG 
307-027 
-a 
---
,/,·~ 
3-19 
3. Measure: 
•Piston pin hole inside diameter 
Use a micrometer. 
Out of specification---+Replace. 
Standard diameter: 
12.0 mm (0.4724 in) 
Piston 
pin wear limit: 
11.95 mm (0.470 in) 
Piston  rings 
1. Measure: 
•Piston ring end gap 
Use a thickness  gauge. 
Out of specification---+Replace. 
NOTE=------------­
You can not measure end gap on expander 
spacer of oil control ring. If control ring rails 
show excessive  gap, replace all three rings. 
I~ 
Piston ring end gap: 
Top  ring: 
0.1..,  0.25 mm 
(0.004 .., 0.01 in) 
2nd ring: 
0.1.., 0.25 mm 
(0.004 .., 0.01 in) 
Oil ring: 
0.2.., 0.4mm 
(0.008 .., 0.015 in) 
2. Measure: 
•Piston ring side clearance 
Use a thickness  gauge. 
Out of specification---+Replace. 
NOTE=------------­
Ciean carbon from piston ring grooves and 
rings  before  measuring  side 
clearance. 
Piston ring side clearance: 
Top ring: 
0.06mm 
(0.002 in) 
2nd ring: 
0.04mm 
(0.001 in)