Page 36 of 287

GEN
INFO
1 - 6
SPECIAL TOOLS
EC140001
SPECIAL TOOLS
The proper special tools are necessary for complete and accurate tune-up and assembly. Using the
correct special tool will help prevent damage caused by the use of improper tools or improvised
techniques. The shape and part number used for the special tool differ by country, so two types are
provided. Refer to the list provided to avoid errors when placing an order.
NOTE:
l
For U.S.A. and Canada, use part number starting with “YM-”, “YU-” or “YS-”.
lFor others, use part number starting with “90890-”.
Part number Tool name/How to use Illustration
YU-1083-A
90890-01084
90890-01085Small slide hammer set
Weight
Slide hammer
These tools are used when removing or installing the
rocker arm shafts.YU-1083-A 90890-01084
90890-01085
YU-01268, 90890-01268 Ring nut wrench
This tool is used when loosen the steering ring nut to
specification.YU-01268 90890-01268
YU-03112, 90890-03112 Yamaha pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-03112 90890-03112
YU-8036-1
90890-03113Inductive tachometer
Engine tachometer
This tool is needed for observing engine rpm.YU-8036-1 90890-03113
YM-01253, 90890-01253 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.YM-01253 90890-01253
YM-01300
90890-01294Damper rod holder set
Damper rod holder
Use this tool to remove and install the damper rod.YM-01300 90890-01294
YM-01312-A, 90890-01312Fuel level gauge
This gauge is used to measure the fuel level in the
float chamber.YM-01312-A 90890-01312
Page 56 of 287

SPEC
2 - 1
EC200000
SPECIFICATIONS
EC211000
GENERAL SPECIFICATIONS
Model name: TTR90M
Model code number: 5HN1 (USA-except for California)
5HN2 (USA-for California)
5HN3 (Europe, Oceania)
5HN4 (CDN)
Dimensions:
Overall length 1,525 mm (57.0 in)
Overall width 605 mm (23.8 in)
Overall height 865 mm (34.1 in)
Seat height 625 mm (24.6 in)
Wheelbase 1,040 mm (40.9 in)
Minimum ground clearance 160 mm (6.3 in)
Minimum turning radius 1,328 mm (52.3 in)
Basic weight:
With oil and full fuel tank 64 kg (141 lb)
Engine:
Engine type Air cooled 4-stroke, SOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 89 cm
3
(5.43 cu.in)
Bore
´
stroke 47.0
´
51.8 mm (1.85
´
2.04 in)
Compression ratio 8.5 : 1
Compression pressure (STD) 1,000 kPa (10 kg/cm
2
, 145 psi) at 1,000 r/min
Starting system Kick starter
Lubrication system: Wet sump
Oil type or grade:
Engine oil
Yamalube 4 (20W40) or SAE 20W40 type
SE/SF motor oil (5 ˚C (60 ˚F) or higher)
Yamalube 4 (10W30) or SAE 10W30 type
SE/SF motor oil (–10 ˚C (10 ˚F) or higher)
Oil capacity:
Engine oil
Periodic oil change 0.8 L (0.70 Imp qt, 0.85 US qt)
Total amount 1.0 L (0.88 Imp qt, 1.06 US qt)
Air filter: Wet type element
0 10 30 50 70 90 110 130
-20 -10 01020
30 40 50
õ
˚F
˚C
GENERAL SPECIFICATIONS
2
Page 62 of 287

SPEC
2 - 7
Piston:
Piston to cylinder clearance 0.025 ~ 0.045 mm
(0.0010 ~ 0.0018 in)0.15 mm
(0.0059 in)
Piston size “D” 46.960 ~ 46.975 mm
(1.8488 ~ 1.8494 in)----
Measuring point “H” 4 mm (0.16 in) ----
Piston off-set 0.75 mm (0.0295 in) ----
Piston pin bore inside diameter 13.002 ~ 13.013 mm
(0.5119 ~ 0.5123 in)13.045 mm
(0.5136 in)
Piston pin outside diameter 12.996 ~ 13.000 mm
(0.5117 ~ 0.5118 in)12.98 mm
(0.511 in)
Piston rings:
Top ring
Type Barrel ----
Dimensions (B
´
T) 1.0
´
2.0 mm (0.04
´
0.08 in) ----
End gap (installed) 0.10 ~ 0.25 mm
(0.004 ~ 0.010 in)0.4 mm
(0.016 in)
Side clearance (installed) 0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)0.12 mm
(0.005 in)
2nd ring
Type Taper ----
Dimensions (B
´
T) 1.0
´
2.0 mm (0.04
´
0.08 in) ----
End gap (installed) 0.10 ~ 0.25 mm
(0.004 ~ 0.010 in)0.4 mm
(0.016 in)
Side clearance 0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)0.12 mm
(0.005 in)
Oil ring
Dimensions (B
´
T) 2.0
´
2.3 mm (0.08
´
0.09 in) ----
End gap (installed) 0.2 ~ 0.7 mm (0.01 ~ 0.03 in) ----Item Standard Limit
H
D
T
B
B
T
B
T
MAINTENANCE SPECIFICATIONS
Page 64 of 287
SPEC
2 - 9
Lubrication system:
Oil filter type Wire mesh type ----
Oil pump type Trochoid type ----
Tip clearance “A” or “B” 0.15 mm
(0.0059 in)0.2 mm
(0.0079 in)
Side clearance 0.06 ~ 0.10 mm
(0.0024 ~ 0.0039 in)0.15 mm
(0.0059 in)
Housing and rotor clearance 0.13 ~ 0.18 mm
(0.0051 ~ 0.0071 in)0.23 mm
(0.0091 in) Item Standard Limit
MAINTENANCE SPECIFICATIONS
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SPEC
2 - 11
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing
Angular bearing----
Front suspension:
Front fork travel 110 mm (4.33 in) ----
Fork spring free length 425.1 mm (16.74 in) 417 mm (16.4 in)
Fork spring fitting length 415.1 mm (16.34 in) ----
Spring rate, STD K = 3.4 N/mm
(0.35 kg/mm, 19.41 lb/in)----
Optional spring/spacer No ----
Oil capacity 64 cm
3
(2.26 lmp oz, 2.16 US oz) ----
Oil level 185 mm (7.28 in) ----
Oil grade Fork oil 15W or equivalent ----
Rear suspension:
Shock absorber travel 48 mm (1.89 in) ----
Spring free length 169 mm (6.65 in) ----
Fitting length 165 mm (6.5 in) ----
Spring rate, STD K = 45.6 N/mm
(4.6 kg/mm, 260 lb/in)----
Optional spring No ----
Enclosed gas pressure 2,000 kPa
(20 kg/cm
2
, 290 psi)----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)
Side clearance ---- 0.3 mm (0.01 in)
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/Material 14
´
1.40/Steel ----
Rear rim size/Material 12
´
1.60/Steel ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/Manufacturer 420/DAIDO ----
Number of links 86 links ----
Chain slack 40 ~ 53 mm (1.6 ~ 2.1 in) ----
Chain length (10 links) ---- 152.5 mm
(6.00 in)
MAINTENANCE SPECIFICATIONS
Page 69 of 287
SPEC
2 - 14
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Ignition timing (B.T.D.C.) 15˚/1,700 r/min
Advancer type Electrical ----
C.D.I.:
Magneto-model/manufacturer F5HN/YAMAHA ----
Source coil resistance (color) 688 ~ 1,032
W
at 20 ˚C (68 ˚F)
(Brown – Green)----
Pickup coil resistance (color) 248 ~ 372
W
at 20 ˚C (68 ˚F)
(Red – White)----
CDI unit-model/manufacturer 4GL/YAMAHA ----
Ignition coil:
Model/manufacturer 2JN/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.18 ~ 0.28
W
at 20 ˚C (68 ˚F) ----
Secondary winding resistance 6.3 ~ 9.5 k
W
at 20 ˚C (68 ˚F) ----
Spark plug cap:
Type Resin ----
Resistance 10 k
W
at 20 ˚C (68 ˚F) ----
MAINTENANCE SPECIFICATIONS
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2 - 11
SPEC
CARACTERISTIQUES D’ENTRETIEN
PARTIE-CYCLE
Désignation Standard Limite
Système de direction:
Type de roulement de direction Roulement à rouleaux coniques
Roulement à contact oblique----
Suspension avant:
Débattement de fourche avant 110 mm (4,33 in) ----
Longueur libre de ressort de fourche 425,1 mm (16,74 in) 417 mm (16,4 in)
Longueur de ressort de fourche installé 415,1 mm (16,34 in) ----
Constante standard de ressort K = 3,4 N/mm
(0,35 kg/mm, 19,41 lb/in)----
Ressort/entretoise en option Non ----
Capacité d’huile 64 cm
3
(2,26 Imp oz, 2,16 US oz) ----
Niveau d’huile 185 mm (7,28 in) ----
Grade d’huile Huile de fourche 15W ou huile équiva-
lente----
Suspension arrière:
Débattement d’amortisseur 48 mm (1,89 in) ----
Longueur libre de ressort 169 mm (6,65 in) ----
Longueur monté 165 mm (6,5 in) ----
Constante standard de ressort K = 45,6 N/mm
(4,6 kg/mm, 260 lb/in)----
Ressort optionnel Non ----
Pression du gaz 2.000 kPa
(20 kg/cm
2
, 290 psi)----
Bras oscillant:
Limite de jeu du bras oscillant
A l’extrémité ---- 1,0 mm (0,04 in)
Latéral ---- 0,3 mm (0,01 in)
Roue:
Type de roue avant Roue à rayons ----
Type de roue arrière Roue à rayons ----
Taille/matériau de jante avant 14
´
1,40/acier ----
Taille/matériau de jante arrière 12
´
1,60/acier ----
Limite de voile de jante:
Radial ---- 2,0 mm (0,08 in)
Latéral ---- 2,0 mm (0,08 in)
Chaîne de transmission:
Type/fabricant 420/DAIDO ----
Nombre de maillons 86 maillons ----
Flèche de la chaîne 40 à 53 mm (1,6 à 2,1 in) ----
Longueur de chaîne (10 maillons) ---- 152,5 mm (6,00 in)
Page 109 of 287

3 - 2
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
*: Since these items requires special tools data and technical skills, they should be serviced.
SERVICE NOTES:
No. 1. DRIVE CHAIN: In addition to tension and alignment, chain must be lubricated every
0.5 ~ 1.0 hour. If unit is subjected to extremely hard usage and wet weather riding, chain
must be checked constantly. See “Lubrication Intervals” for additional details.
No. 2. AIR FILTER: Remove and clean filter every 20 ~ 40 hours.
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EC321000
GENERAL INSPECTION AND MAINTENANCE
* Chassis fastenersMake sure that all nuts, bolts and screws are
properly tightened.
Tighten if necessary.
SidestandCheck operation.
Lubricate and repair if necessary.
* Spark arrester Clean.
* Front forkCheck operation and for oil leakage.
Correct accordingly.
*Rear shock
absorber assemblyCheck operation and shock absorber for oil
leakage.
Replace shock absorber assembly if necessary.
Item Routine Page
Brake Check operation/adjustment. P3-11
Engine oil Change oil as required. P3-5 ~ 7
Drive chain Check alignment/adjustment/lubrication. P3-12
Spark plug Check color/condition. P3-19
Throttle Check for proper throttle cable operation. P3-3
Air filter Foam type – must be clean and damp w/oil always P3-3 ~ 4
Wheels and tires Check pressure/runout/spoke tightness/bead stopper/axle nuts. P3-15 ~ 17
Fittings/fasteners Check all – tighten as necessary. —Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
3