Engine Top End - Yamaha MM700A Manual

ENGINE
8. If equipped with a battery, connect the negative battery
cable to the engine.
9. Attach the crankcase pulse hose (Figure 10).
10. Attach the oil hoses to the oil pump (B. Figure
11. Connect the oil pump control cable (A, Figure 9).
ure 8) on both sides of the engine and tighten to the torque
specified in Figure 11.
13. Connect the magnetoJgenerator connectors (Figure
14. Connect the lower coolant hose to the coolant pump.
15. Connect the coolant temperature connector (B, Fig-
ure
16. Connect the upper coolant hose (A, Figure 4) and
carburetor heater hose (Figure 5) to the engine.
Three.
19. Install the drive belt as described in Chapter Ten.
20. Install the recoil starter as described in Chapter Nine.
ter Five.
22. Install the exhaust assembly as described in Chapter
Five.
23. If equipped with a battery, connect the negative bat-
tery cable to the battery.
24. Install the shroud.

ENGINE TOP END

The engine top end consists of the cylinder head, cylin-
ders, pistons, piston rings, piston pins and the connecting
rod small-end bearings.
It is possible to service the engine top end with the en-
gine installed in the frame; however, the following service
procedures are shown with the engine removed for clarity.
Refer to Figure 12 when servicing the engine top end.
Cylinder Head
CAUTION
prevent warp and damage to any cornpo-
To
nent, remove the cylinder head only when
the engine has cooled to room temperature.
the
Never pry cylinder head when trying to
remove it.
NOTE
I f disassembli~~g the engine for inspection,
check the compression as described in
Chapter Three before disassembly.
lowing:
a. Open the shroud.
9).
b. Drain the cooling system as described in Chapter
Three.
7 and Fig-
Disconnect the coolant hose (A, Figure 4) and cool-
ant temperature connector
d. Disconnect the carburetor heater hose (A, Figure
13) from the engine.
e. Disconnect the spark plug cables from the spark
plugs.
2. Loosen, but do not remove, the spark plugs so they can
be removed later.
head evenly to prevent warpagc.
4. Remove the cylinder head nuts. Loosen the cylinder
head by tapping around the outer edge with a rubber or
plastic mallet. Then remove the cylinder head.
5. Remove the cylinder head gaskets (A, Figure 14).
6. Lay a rag over the open cylinders to prevent dirt from
falling into the cylinders or water passages.
7. Inspect the cylinder head as described in this chapter.
After removing the cylinder head, check the
retaining studs
threads or other damage. Make sure the
studs are tight in the cylinders. Ifnecessary,
remove the cylinder and replace damaged
studs.
sure the UP mark on the head gasket is visible (Figure
15).
finger-tight.
10. Tighten the retaining nuts in two steps. Tighten the
nuts in the sequence shown in Figure 16 to a torque of 11
quence to 23 N*-m (17 fk-lb.).
11. Install the spark plugs.
12. If the engine is installed in the frame, perform the fol-
lowing:
a. Connect the spark plug cables to the spark plugs.
b. Connect the coolant hose (A, Figure 4) and coolant
temperature connector
to the engine.
d. Refill the cooling system as described in Chapter
Three.
NOTE
Figure 14) for stripped
99