Page 60 of 99
PERIODIC MAINTENANCE AND MINOR REPAIR
6-14
6 6. Remove the air filter case cover by
removing the screws.7. Remove the air filter. 8. Tap the air filter lightly to remove
most of the dust and dirt. Blow out
the remaining dirt with com-
pressed air as shown. If the air fil-
ter is damaged, replace it.
9. Install by reversing the removal
procedure.
EWA00013
WARNING
@ Make sure that the fuel hose and
breather hose are properly connect-
ed, in place and not pinched. If a
hose is damaged, be sure to replace
it. @
1. Air filter case cover
2. Screw (´ 3)
1. Air filter
E_4tx_Periodic.fm Page 14 Saturday, October 16, 1999 9:37 AM
Page 62 of 99
PERIODIC MAINTENANCE AND MINOR REPAIR
6-16
6
NOTE:@ If the specified idle speed cannot be
obtained by performing the above ad-
justment, consult a Yamaha dealer. @
EAU00635
Throttle cable free play
inspectionThere should be a free play of 3 ~
5 mm at the throttle grip. If the free play
is incorrect, ask a Yamaha dealer to
make this adjustment.
EAU00637
Valve clearance adjustmentThe correct valve clearance changes
with use, resulting in improper fuel/air
supply or engine noise. To prevent this,
the valve clearance must be adjusted
regularly. This adjustment however,
should be left to a professional
Yamaha service technician. Standard idle speed:
1,050 ~ 1,250 r/min
a. Free play
E_4tx_Periodic.fm Page 16 Saturday, October 16, 1999 9:37 AM
Page 78 of 99

PERIODIC MAINTENANCE AND MINOR REPAIR
6-32
6
EAU01095
Turn signal light bulb
replacement1. Remove the screw and the lens.
2. Remove the defective bulb by
pushing it inward and turning it
counterclockwise.
3. Install a new bulb by pushing it in-
ward and turning it clockwise.
4. Install the lens and tighten the
screw.
EAU01008
TroubleshootingAlthough Yamaha motorcycles receive
a rigid inspection before shipment from
the factory, trouble may occur during
operation.
Any problem in the fuel, compression,
or ignition systems can cause poor
starting and loss of power. The trouble-
shooting chart describes a quick, easy
procedure for making checks.
If your motorcycle requires any repair,
bring it to a Yamaha dealer. The skilled
technicians at a Yamaha dealership
have the tools, experience, and know-
how to properly service your motor-
cycle. Use only genuine Yamaha parts
on your motorcycle. Imitation parts may
look like Yamaha parts, but they are of-
ten inferior. Consequently, they have a
shorter service life and can lead to ex-
pensive repair bills.
1. Screw
2. Lens
1. Bulb
E_4tx_Periodic.fm Page 32 Saturday, October 16, 1999 9:37 AM
Page 79 of 99
PERIODIC MAINTENANCE AND MINOR REPAIR
6-33
6
EAU02990*
Troubleshooting chart
EW000125
WARNING
@ Never check the fuel system while smoking or in the vicinity of an open flame. @
Check if there is fuel
in the fuel tank.1. Fuel
Enough fuel.
No fuel.
Go to compression check.
Supply fuel.
Engine doesn’t start, go to compression check.
Use the electric starter.2. Compression
There is compression.
No compression.
Go to ignition check.
Ask a Yamaha dealer to
inspect.
Remove spark plugs
and check electrodes.3. Ignition
Wet.
Dry.
Wipe clean with dry cloth and correct
spark gap or replace spark plugs.
Ask a Yamaha dealer to inspect.
Engine doesn’t start, ask a Yamaha
dealer to inspect.Engine doesn’t start, go to battery
check.Open throttle half-way and start
the engine.
Use the electric starter.4. Battery
Engine turns over
quickly.
Engine turns over
slowly.
Battery good.Check connections or
recharge.
E_4tx_Periodic.fm Page 33 Saturday, October 16, 1999 9:37 AM
Page 84 of 99

MOTORCYCLE CARE AND STORAGE
7-2
7
ECA00010
CAUTION:@ l
Avoid using strong acidic wheel
cleaners, especially on spoked
wheels. If you do use such
products for hard-to-remove
dirt, do not leave it on any long-
er than instructed, then thor-
oughly rinse it off with water,
immediately dry the area and
apply a corrosion protection
spray.
l
Improper cleaning can damage
windshields, cowlings, panels
and other plastic parts. Use
only a soft, clean cloth or
sponge with mild detergent and
water to clean plastic.
l
Do not use any harsh chemical
products on plastic parts. Be
sure to avoid using cloths or
sponges which have been in
contact with strong or abrasive
cleaning products, solvent or
thinner, fuel (gasoline), rust re-
movers or inhibitors, brake flu-
id, antifreeze or electrolyte.
l
Do not use high-pressure wash-
ers or steam-jet cleaners since
they cause water seepage and
deterioration in the following ar-
eas: seals (of wheel bearings,
swingarm bearings, forks and
brakes), electric components
(couplers, connectors, instru-
ments, switches and lights),
breather hoses and vents.
l
For motorcycles equipped with
a windshield: Do not use strong
cleaners or hard sponges as
they will cause dulling or
scratching. Some cleaning
compounds for plastic may
leave scratches on the wind-
shield. Test the product on a
small hidden part of the wind-
shield to make sure they do not
leave any marks. If the wind-
shield is scratched, use a quali-
ty plastic polishing compound
after washing.
@After riding in the rain, near the sea oron salt-sprayed roadsSince sea salt or salt sprayed on the
roads in the winter are extremely corro-
sive in combination with water, carry
out the following steps after each ride
in the rain, near the sea or on salt-
sprayed roads. (Salt sprayed in the
winter may remain on the roads well
into spring.)
E_4tx_Cleaning.fm Page 2 Saturday, October 16, 1999 9:38 AM
Page 86 of 99

MOTORCYCLE CARE AND STORAGE
7-4
7
ECA00013
CAUTION:@ l
Apply spray oil and wax spar-
ingly and wipe off any excess.
l
Never apply oil or wax on rub-
ber and plastic parts, but treat
them with a suitable care prod-
uct.
l
Avoid using abrasive polishing
compounds as they wear away
the paint.
@NOTE:@ Consult a Yamaha dealer for advice on
what products to use. @
StorageShort-term
Always store your motorcycle in a cool,
dry place and, if necessary, protect it
against dust with a porous cover.
ECA00014
CAUTION:@ l
Storing the motorcycle in a
poorly ventilated room or cover-
ing it with a tarp while it is still
wet will allow water and humidi-
ty to seep in and cause rust.
l
To prevent corrosion, avoid
damp cellars, stables (because
of the presence of ammonia)
and areas where strong chemi-
cals are stored.
@
Long-term
Before storing your motorcycle for
several months:
1. Follow all the instructions in the
“Care” section of this chapter.
2. Drain the carburetor float cham-
bers by loosening the drain bolts;
this will prevent fuel deposits from
building up. Pour the drained fuel
into the fuel tank.
3. Only for motorcycles equipped
with a fuel cock which has an
“OFF” position: Turn the fuel cock
to “OFF”.
4. Fill up the fuel tank and add fuel
stabilizer (if available) to prevent
the fuel tank from rusting and the
fuel from deteriorating.
5. Perform the following steps to pro-
tect the cylinders, piston rings, etc.
from corrosion.
E_4tx_Cleaning.fm Page 4 Saturday, October 16, 1999 9:38 AM
Page 89 of 99

8-1
8
EAU01038
8-SPECIFICATIONSSpecifications
Model TDM850
Dimensions
Overall length 2,165 mm
(for GB, NL, B, F, E, P, I, GR, D,
DK)
2,200 mm (for N, S, SF)
Overall width 790 mm
Overall height 1,285 mm
Seat height 805 mm
Wheelbase 1,475 mm
Ground clearance 165 mm
Minimum turning radius 2,900 mm
Basic weight (with oil and full
fuel tank)
232 kg
Engine
Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Forward inclined parallel
2-cylinder
Displacement 849 cm
3
Bore ´ Stroke 89.5 ´ 67.5 mm
Compression ratio 10.5:1
Starting system Electric starter
Lubrication system Dry sumpEngine oil
Ty p e
Recommended engine oil
classification API Service SE, SF, SG type or
higher
Quantity
Periodic oil change 3.5 L
With oil filter replacement 3.6 L
Total amount 4.2 L
Cooling system capacity
(total amount)
1.7 L
-20˚ -10˚ 0˚
10˚20˚ 30˚
40˚50˚C
SAE 10W/30
SAE 15W/40SAE 20W/40SAE 20W/50
SAE 10W/40
CAUTION:Be sure to use motor oils that do not contain anti-friction
modifiers. Passenger car motor oils (often labeled
“Energy Conserving”) contain anti-friction additives which
will cause clutch and/or starter clutch slippage, resulting in
reduced component life and poor engine performance.
E_4tx_Spec.fm Page 1 Saturday, October 16, 1999 9:38 AM
Page 90 of 99
SPECIFICATIONS
8-2
8
Air filterDry type element
Fuel
Type Regular unleaded gasoline
Fuel tank capacity 20 L
Reserve amount 3.1 L
Carburetor
Type ´ quantity BDSR38 ´ 2
Manufacturer MIKUNI
Spark plug
Manufacturer/Type NGK / DPR8EA-9 or
DENSO / X24EPR-U9
Gap 0.8 ~ 0.9 mm
Clutch typeWet, multiple-disc
Transmission
Primary reduction system Spur gear
Primary reduction ratio 1.718
Secondary reduction system Chain drive
Secondary reduction ratio 2.688
Number of sprocket teeth
(rear/front) 43/16
Transmission type Constant mesh 5-speed
Operation Left foot operationGear ratio
1st 2.643
2nd 1.947
3rd 1.500
4th 1.174
5th 0.964
Chassis
Frame type Diamond
Caster angle 24.5°
Trail 103 mm
Tires
Front
Type Tubeless
Size 110/80 ZR18 (58W)
Manufacturer/
model Bridgestone / BT54F
Michelin / MACADAM 90X
Pirelli / MTR03
Rear
Type Tubeless
Size 150/70 ZR17 (69W)
Manufacturer/
model Bridgestone / BT54R
Michelin / MACADAM 90X
Pirelli / MTR04
E_4tx_Spec.fm Page 2 Saturday, October 16, 1999 9:38 AM