Kymco MO KXR 50 Service Manual - chap 05 (alimentazione)

5. FUEL SYSTEM

5-0

Mongoose/KXR 90/50

5

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FUEL SYSTEM

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SERVICE INFORMATION -------------------------------------------- 5- 2

FUEL TANK------------------------------------------------------------- 5- 4

FUEL VALVE REMOVAL -------------------------------------------- 5- 4

THROTTLE VALVE ----------------------------------------------------- 5- 7

AIR CLEANER ---------------------------------------------------------- 5- 9

CARBURETOR ---------------------------------------------------------- 5-11

REED VAVLE (Mongoose/KXR 50) ---------------------------------- 5-16

5

5. FUEL SYSTEM

5-1

Mongoose/KXR 90/50

5. FUEL SYSTEM

5-2

Mongoose/KXR 90/50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• Do not bend or twist control cables. Damaged control cables will not operate smoothly.

• When disassembling fuel system parts, note the locations of O-rings. Replace them with new

ones during reassembly.

• Before float chamber disassembly, loosen the drain screw to drain the residual gasoline into a

clean container.

• After the carburetor is removed, plug the intake manifold side with a clean shop towel to prevent

foreign matters from entering.

• When cleaning the carburetor air and fuel jets, the O-rings and diaphragm must be removed first to

avoid damage. Then, clean with compressed air.

• When the machine is not used for over one month, drain the residual gasoline from the float

chamber to avoid erratic idling and clogged slow jet due to deteriorated fuel.

SPECIFICATIONS

Item

Standard(Mongoose/KXR 90)

Standard(Mongoose/KXR 50)

Type

PB

Venturi dia.

f14

Slow jet No.

#35

#38

Main jet No.

#100

#80

Adjust method

Piston

Idle speed

1700±100rpm

2000±100rpm

Throttle grip free play

1_ 4mm

Float level

8.0mm

Air screw opening

1±1/4

Gasoline is very dangerous. When working with gasoline, keep sparks and flames away from the working area. Gasoline is extremely flammable and is explosive under certain conditions. Be sure to work in a well-ventilated area.

5. FUEL SYSTEM

5-3

Mongoose/KXR 90/50

SPECIAL TOOL

Float level gauge

TROUBLESHOOTING

Engine cranks but won’t start Engine lacks power

• No fuel in tank • Clogged air cleaner

• No fuel to carburetor • Faulty carburetor

• Cylinder flooded with fuel • Faulty ignition system

• No spark at plug

• Clogged air cleaner Lean mixture

• Intake air leak • Clogged carburetor fuel jets

• Improper throttle operation • Float level too low

• Intake air leak

Engine idles roughly, stalls or runs poorly • Clogged fuel tank cap breather hole

• Faulty auto bystarter • Bent, kinked or restricted fuel line

• Ignition malfunction

• Faulty carburetor Rich mixture

• Poor quality fuel • Float level too high

• Lean or rich mixture • Clogged air jets

• Incorrect idle speed • Clogged air cleaner

Misfiring during acceleration

• Faulty ignition system

• Faulty carburetor

Backfiring at deceleration

• Float level too low

• Incorrectly adjusted carburetor

• Faulty exhaust muffler

5. FUEL SYSTEM

5-4

Mongoose/KXR 90/50

FUEL TANK

REMOVAL

Remove front fender (See page 2-5).

Switch the fuel valve “OFF”. Disconnect the fuel outlet tube from fuel valve. Remove two screws attaching the fuel valve and holder.

Remove the two bolts and then remove the fuel tank.

INSTALLATION

Reverse the “FUEL TANK REMOVAL” procedures.

FUEL VALVE

REMOVAL

Remove the screw and then remove control switch. Disconnect all fuel tubes and then remove fuel valve.

Warning

Fuel Tank

Screw

Fuel Valve

Bolts

Fuel Outlet Tube

• Keep sparks and flames away from the

work area.

• Wipe off any spilled gasoline.

Control Switch

Fuel Tubes

Screws

• Keep sparks and flames away from the

work area.

• Drain gasoline into a clean container.

°Ø

5. FUEL SYSTEM

5-5

Mongoose/KXR 90/50

DISASSEMBLY

Remove the two screws on the retaining ring and then remove retaining ring. Remove the washer and control shaft.

Remove the rubber gasket from the fuel valve body.

INSPECTION

Inspect the fuel valve body for dirt and clog. Clean if necessary.

Replace the rubber gasket with new ones if they are damaged or deteriorated.

Replace the O-rings with new ones if they are damaged or deteriorated.

ASSEMBLY

Reverse the “DISASSEMBLY” procedures. Install rubber gasket, control shaft, washer

and retaining ring.

Fuel Valve Body

Control Shaft

Rubber Gasket

Retaining Ring

Washer

Screws

Control Shaft

O-ring

• Aligning the tab on the control shaft

with the outlet duct in the fuel valve body.

• Aligning the tab on the retaining ring

with the outlet duct in the fuel valve body.

°Ø

Tab

Outlet Duct

Tab