General Information; Operations Possible With The Engine In The Frame; Operations Requiring Engine Removal; Major Engine Repair - General Note - Yamaha TDM850 User Manual

2*6 Engine, clutch and transmission
Torque settings (continued)
Outer sprocket cover bolts .............................................................................
Oil pump mounting screws .............................................................................
Oil pump assembly screw ...........................................................................
Oil pump cover bolts ...................................................................................
Oil pipe to oil pump cover bolts ......................................................................
Oil pipe banjo bolts to crankcase cover/oil tank and cylinder head ....
Oil pipe to oil tank bolts .................................................................................
Oil pressure relief valve holder bolt ..............................................................
Oil strainer cover screws ............................................................................
Oil sump bolts ................................................................................................
Oil hose union to crankcase bolts ................................................................
Balancer shaft holder bolts ............................................................................
Balancer shaft retainer plate Torx bolt ..........................................................
Oil strainer holder bolts ..............................................................................
Crankcase top cover bolts (1991 to 1995 TDM models and
all XTZ models) .........................................................................................
Crankcase 6 mm bolts .................................................................................
Crankcase 8 mm bolts .................................................................................
Crankcase 10 mm bolts ...............................................................................
Connecting rod cap nuts
Initial setting
1991 to 1995 TDM models and all XTZ models ....................................
1996-on TDM models and all TRX models ...........................................
Final setting (all models) ...........................................................................
Transmission output shaft retainer plate bolts {left-hand side) ....................
Transmission input shaft bearing retainer Torx screws .................................
Oil gallery bolt ...............................................................................................

1 General information

The engine/transmission unit is a liquid-cooled
parallel twin with five valves per cylinder (three
inlet and two exhaust). The valves are operated
by double overhead camshafts which are chain
driven off the crankshaft.
engine/transmission assembly is constructed
from aluminium alloy. The crankcase is divided
horizontally.
The crankcase incorporates a dry sump,
pressure-fed lubrication system which uses two
gear-driven oil pumps, one a feed pump to
lubricate the engine, the other a scavenge pump
to return oil to the tank, both driven off the
crankshaft. The sump houses the oil filter, by-
pass valve assembly and relief valve. The oil
tank is mounted behind the engine on 1991 to
1995 TDM models and all XTZ models, and on
the engine behind the cylinders on later TDM
models and all TRX models. The oil pumps are
gear driven off the crankshaft.
The crankshaft also drives two balancer shafts
which eliminate the vibration inherent in parallel
twin engines
The alternator and starter clutch are on the
left-hand end of the crankshaft.
Power from the crankshaft is routed to the
transmission via the clutch. The clutch is of the
wet, multi-plate type and is gear-driven off
5 Nm
6 Nm
6 Nm
10Nm
10 Nm
21 Nm
10 Nm
10Nm
7 Nm
10 Nm
10 Nm
10 Nm
12 Nm
10 Nm
10 Nm
12 Nm
24 Nm
40 Nm
46 Nm
35 Nm
48 Nm
10 Nm
12 Nm
10 Nm
the crankshaft. The transmission is a five-speed
constant-mesh unit. Final drive to the rear wheel
is by chain and sprockets.
2 Operations possible with the
engine in the frame
The
The components and assemblies listed below
can be removed without having to remove the
engine/transmission assembly from the frame. If
however, a number of areas require attention at
the same time, removal of the engine is
recommended.
Valve cover
Camshafts
Cylinder head
Cylinder block, pistons and piston rings
Pick-up coil assembly
Clutch
Gearchange mechanism (external
components)
Alternator
Starter clutch
Oil filter
Oil pumps, oil strainer, oil pressure relief valve
and by-pass valve
Starter motor
Water pump
Balancer shafts (1991 to 1995 TDM and all
XTZ models)
Cam chain
Operations requiring engine
removal
It is necessary to remove
engine/transmission assembly from the frame to
gain access to the following components.
Transmission shafts
Selector drum and forks
Connecting rods and bearings
Crankshaft and bearings
Balancer shafts (1996-on TDM models and all
TRX models)
4 Major engine repair -
general note
1 It is not always easy to determine
when or if an engine should be completely
overhauled, as a number of factors must be
considered.
2 High mileage is not necessarily an indication
that an overhaul is needed, while low mileage, on
the other hand, does not preclude the need for
an overhaul. Frequency of servicing is probably
the single most important consideration. An
engine that has regular and frequent oil and filter
changes, as well as other required maintenance,
will most likely give many miles of reliable
service.
the
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