Chapter 4. Carburetor and Air Cleaner

CARBURETOR

Section View

1	Diaphragm	8	Pilot Jet
2	Piston valve	9	Pilot Air Jet
3	Main air jet	10	Throttle Valve
4	Jet needle	11	By-pass hole
5	Needle jet	12	Pilot Outlet
6	Float chamber	13	Pilot Screw
7	Main jet	14	Spring

Specifications

Main jet	#106
Jet needle	Y-18
Pilot jet	#41
Starter jet	#43
Fuel level	1.0 ± 1 mm (0.0394 ± 0.039 in.)
Pilot screw	Preset
Float valve seat	02.0
Engine idle speed	1,100 +50 r/min

CAUTION: The pilot screw settings are adjusted for maximum performance at the factory attempt to change these settings as any alteration will decrease engine performance.

 

CARBURETOR

 

1.	Vacuum chamber cover	12.	Throttle stop screw
2.	Float chamber cover	13.	Drain screw
3.	Starter plunger	14.	Float pin
4.	Jet needle cover	15.	Float
5.	Set spring	16.	Pilot jet
6.	Jet needle	17.	Float valve
7.	Vacuum piston	18.	Float valve washer
8.	Main nozzle	19.	Main jet
9.	Clutch wire clip	20.	Main jet washer
10.	Synchronizing screw	21.	Upper support plate
11.	Starter lever shaft	22.	Lower support plate

FUEL LEVEL

* 1.0 ± 1 mm (0.0394 ± 0.039 in)

 

Disassembly

CAUTION: Separation of the carburetor is not recommended. Usual disassmebly for cleaning and inspection is not necessary to separate the carburetors. The carburetor body support screws are locked with a locking compound such "LOCTITE". If the carburetors are separated, misalignment will result.

Remove:

•   Vacuum chamber cover

•   Vacuum piston

•   Jet needle

•   Main air jet 1

•   Pilot air jet 2

•   Main nozzle

•   Starter plunger

Remove:

•   Float chamber cover

•   Pilot jet 1

•   Main jet 2

Remove:

•   Float pin 1

•   Float

•   Float valve

•   Float valve seat

Inspection

Check:

•   Carburetor body and fuel passage

If contaminated: Wash carburetor in petroleum-based solvent (Do not use any caustic carburetor cleaning solution). Blow out all passages and jets with compressed air.

•   Floats

If damaged, replace.

Check:

•   Float needle valve and seat

Wear, contamination -» Replace as a set.

Check:

•   Vacuum piston and rubber diaphragm

Scratches (piston), Tears (diaphragm) -> Replace as a set.

•   Jet needle

Bends, wear -> Replace.

Check:

• Starter plunger

Wear, damage -> Replace.

Assembly

Reverse disassembly steps. Pay close attention to installation of vacuum piston diaphragm and location of each jet.

NOTE: Note position of tab on diaphragm. This tab must be placed in the cavity of the carburetor body during assembly.

If the carburetors are separated, place the carburetors on a surface plate 2 and install lower 1 and upper support plate.

Apply loctite ® Stud N' Bearing Mount (red) to securing screws.

Fuel level Adjustment

NOTE: Place motorcycle on level surface before checking fuel level.

Connect:

•   Fuel level gauge 1 or 6 mm (0.24 in.) vinyl pipe.

Place:

•   Fuel level gauge to carburetor mixing chamber body.

Loosen:

•   Drain screw 2 .

Set:

•   Fuel cock to "ON" or "RES" and start engine. Stop it after a few minutes.

Check:

•   Fuel level 1 should be within specified range.

Fuel level

1.0 ± 1 mm (0.0394 ± 0.039 in.) below from the carburetor mixing chamber body edge.

NOTE: Fuel level of each left and right side carburetor shouled be equal. If not, place a suitable size of wooden piece or the like under the center stand and adjust then check fuel level again.

•   Remove carburetors and check fuel valve and float assembly if fuel level is not within specified range.

•   If no damage is found in these parts, adjust float level by slightly bending tang 1 of float. Recheck fuel level.

•   Repeat these steps for other carburetors.

AIR CLEANER AND CRANKCASE VENTILATION SYSTEM

Refer to AIR FILTER for the air cleaner maintenance.