YAMAHA YFM90R 2021 Owner's Guide

5-4
5
3. Tighten the locknut.
Engine speed limiter plate
When the engine speed limiter plate is installed,
engine speed is limited to 4900 r/min. When this
plate is removed, top engine speed (8500 r/min) is
available.
Remove the plate as follows. 1. Remove the seat. (See page 5-13.)
2. Loosen the screws, and then remove the plate as shown. 3. Tighten the screws.
4. Install the seat.
TIPStore the engine speed limiter plate with the Own-
er’s Manual so that it is readily available whenever
you want to reduce top engine speed.
1. Locknut
2. Adjusting screw
3. No more than 14.5 mm (0.57 in)
1
3
2
(b)
(a)
1. Screw
2. Engine speed limiter plate
12
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5-5
5
EBU18393Front brake leverThe front brake lever is located on the right han-
dlebar. To apply the front brake, pull the brake le-
ver toward the handlebar grip.
EBU18403Rear brake leverThe rear brake lever is located on the left handle-
bar. To apply the rear brake, pull the brake lever
toward the handlebar grip.EBU18462Parking brakeUse the parking brake before starting the engine
or after parking the ATV, especially on a slope. Ap-
ply the rear brake lever and push down the lock
plate to apply the parking brake. Squeeze the rear
brake lever to release the parking brake.
1. Front brake lever
1
1. Rear brake lever
1
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5-6
5
WARNING
EWB00221Always set the parking brake before starting
the engine. The ATV could start moving un-
expectedly if the parking brake is not ap-
plied. This could cause loss of control or a
collision.
 Always be sure you have released the park-
ing brake before you begin to ride. The brake
could overheat if you ride the ATV without re-
leasing the parking brake. You could lose braking performance which could cause an
accident. You could also wear out the brakes
prematurely.
EBU18583Drive select leverThe drive select lever is used to shift the transmis-
sion into the forward, neutral and reverse posi-
tions. See page 7-3 for drive select lever
operation.
1. Parking brake lock plate
1
1. Drive select lever
1
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5-7
5
EBU33893KickstarterUse the kickstarter to start the engine when the
battery voltage is low. 1. Remove the seat (page 5-13), and then re- move the kickstarter lever.
2. Remove the kickstarter lever cap. 3. Install the kickstarter lever.
4. Move the kickstarter lever down lightly with
your foot until the gears engage, and then
push it down smoothly but forcefully.1. Kickstarter lever
1
1. Kickstarter lever cap
1
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5-8
5
5. When the engine has started, remove the kickstarter lever and store it under the seat.
6. Install the kickstarter lever cap and the seat.
NOTICEECB02300Do not use the kickstarter if the battery is not
installed or if the battery leads are not connect-
ed.
EBU37980Fuel tank capRemove the fuel tank cap by turning it counter-
clockwise.
WARNING
EWB02522Gasoline and gasoline vapors are extremely
flammable. To avoid fires and explosions and
to reduce the risk of injury when refueling, fol-
low these instructions. 1. Before refueling, turn off the engine and be sure that no one is sitting on the vehicle. Nev-
er refuel while smoking, or while in the vicinity
1. Fold out.
2. Push down.
1
2
1. Fuel tank cap
1
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5-9
5of sparks, open flames, or other sources of
ignition such as the pilot lights of water heat-
ers and clothes dryers.
2. Do not overfill the fuel tank. When refueling, be sure to insert the pump nozzle into the fuel
tank filler hole. Stop filling when the fuel
reaches the bottom of the filler tube. Because
fuel expands when it heats up, heat from the
engine or the sun can cause fuel to spill out of
the fuel tank. 3. Wipe up any spilled fuel immediately.
NOTICE: Immediately wipe off spilled fuel
with a clean, dry, soft cloth, since fuel may
deteriorate painted surfaces or plastic
parts.
[ECB00982]
4. Turn the fuel tank cap fully clockwise to make sure it is securely closed.EBU38650FuelMake sure there is sufficient gasoline in the tank
before starting off. Refuel if necessary.
WARNING
EWB02532Gasoline is poisonous and can cause injury or
death. Handle gasoline with care. Never siphon
gasoline by mouth. If you should swallow some
gasoline or inhale a lot of gasoline vapor, or get
some gasoline in your eyes, see your doctor
immediately. If gasoline spills on your skin,
wash with soap and water. If gasoline spills on
your clothing, change your clothes.
1. Maximum fuel level
2. Fuel tank filler tube
12
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5-10
5
TIPConfirm the gasoline pump nozzle has the same
fuel identification mark.
About the recommended fuel
This model’s engine has been designed to use
regular unleaded gasoline. The research octane
number should be 95 or higher. If knocking or
pinging occurs, try a gasoline of a different brand
or higher octane.TIPGasoline containing ethanol can be used if the
ethanol content does not exceed 10% (E10). Gas-
oline containing methanol is not recommended
because it can cause damage to the fuel system
or vehicle performance problems. NOTICEECB00071Use only unleaded gasoline. The use of leaded
gasoline will cause severe damage to internal
engine parts, such as the valves and piston
rings, as well as to the exhaust system. EBU18821Fuel cockThe fuel cock supplies fuel from the tank to the
carburetor while also filtering it.
The fuel cock lever positions are explained as fol-
lows and shown in the illustrations.
Recommended fuel:
Regular unleaded gasoline (Gasohol [E10]
acceptable)
Fuel tank capacity: 6.6 L (1.7 US gal, 1.5 Imp.gal)
Fuel reserve amount: 0.9 L (0.24 US gal, 0.20 Imp.gal)
1. EN228 fuel identification mark
1
E5
E10
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5-11
5OFF
With the fuel cock lever in this position, fuel will not
flow. Always turn the fuel cock lever to this posi-
tion when the engine is not running. ON
With the fuel cock lever in this position, fuel flows
to the carburetor. Turn the fuel cock lever to this
position when starting the engine and riding.
1. Arrow mark positioned over “OFF”
1
1. Arrow mark positioned over

5-12
5
RES
This indicates reserve. With the fuel cock lever in
this position, the fuel reserve is made available.
Turn the fuel cock lever to this position if you run
out of fuel while riding. When this occurs, refuel as
soon as possible and be sure to turn the fuel cock
lever back to “ON”!
EBU18852Starter (choke) “ ”Starting a cold engine requires a richer air-fuel
mixture. This mixture is controlled by the starter
(choke) system. To use the starter (choke) and enrich the air-fuel
ratio, move the starter (choke) lever in direction (a).
To decrease the starter (choke) or turn it off, move
the starter (choke) lever in direction (b).
TIPSee page 7-1 for engine starting instructions.
1. Arrow mark positioned over “RES”
1
1. Starter (choke) lever
1
(a) (b)
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5-13
5
EBU34551SeatTo remove the seat
Push down on the rear of the seat and pull the seat
lock lever upward to release the seat lock. Then
pull up at the rear of the seat to remove it.To install the seat
Insert the projection on the front of the seat into
the seat holder, and then push down on the seat
at the rear to lock it in place. Make sure that the
seat is securely fitted.
EBU18997Front shock absorbersThe spring preload can be adjusted to suit the rid-
er’s weight and the riding conditions.
1. Seat
2. Seat lock lever
1
2
1. Projection
2. Seat holder
1
2
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