Cleaning carburetor

Identification: Information plate in national language on cross member in front of radiator or on cylinder head cover. Adjust engines according to data of respective exhaust gas information plate.

National version

Idle speed 1/min

Idle speed emission value % CO

up to 1976

max. 1.5

1976

800-900

max. 1.0 without air injection

1976

1973

750-900

up to 1.5

1974 Federal

1974 California

700-900

6—8 without air injection

1975/76

800-900

max. 1.0 without air injection

National version

Engine speed

Vacuum hose pulled off

1/min

Engine speed

Driving position engaged

1/min

TN choke

TN choke

1976

1976

1700-1900

600-700

1973/74

1200-1400

1975/76

M When all auxiliary units are engaged, the engine should still run smoothly.

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Flat roof float

-2 to 6 mm³)

Hip roof float and fuel return valve without fuel pressure regulation

0 mm²)

Hip roof float and fuel return valve with fuel pressure regulation

+ 2 mm²)

!) Measure from parting surface without gasket.

2)   In the event of starting or bypass faults, set 2 mm higher.

3)  Under parting surface.

National version

1976

s) 1976

<&«$> 1973

(usa) 1974 Federal

(usa) 1974 California

1975/76

Carburetor designation

Solex two-stage downdraft carburetor 4 A 1

Carburetor stage

Stage I Stage 11

Stage I Stage II

Stage I Stage 11

Stage I Stage II

Stage I Stage 11

Main jet

X 105 –

X 105 –

X 100

X 112.5 –

X105²) –

Jet needle

A7

A4

A4

A5

A7

Idle speed fuel jet

47.5¹) –

45¹!

45³)

45³)

47.5¹)

Idle speed air jet

102.5¹) –

102.5¹) –

110

100

102.5¹) –

M Combination jet

²)  Model year 1975, size 100

³)  Pressed-in, cannot be disassembled.

Oil telethermometer

116 589 27 21 00

Digital tester

001 589 54 21 00

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Connecting cable 3 m long

000 589 04 90 00

Intermediate plug (adaptor)

000 589 72 63 00

Trigger

000 589 71 63 00

Revolution counter and CO measuring instrument

Puller

refer to Fig. item 9

1    Remove air filter.

2   Thoroughly clean outside of carburetor.

3   Loosen all fastening nuts and screws on carburetor cover. Pull off lock (43) and disconnect choke rod. Unscrew air filter fastening screw.

Press off carburetor cover only at pressing-off point.

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4 Clean filter strainer with compressed air.

5 Unscrew idle speed jets or combination jet (238). Blow out jet and duct with compressed air.

78 Idle speed air jet

Combination jet

238    Idle speed and idle speed fuel jet

239    O-ring

6 Remove main jets (79). Blow out all ducts, bores, riser pipes and jets with compressed air.

Do not clean jets with metallic items (e.g. wire, drill).

79 Main jets stages I 149 Jet needles stage II 158 Riser pipes bypass system stage 11 193 Riser pipes starting mixture enrichment 224 Riser pipe TN choke (thermostatically controlled bypass choke)

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7 Blow out injection bores (arrows) of accelerating pump with compressed air and check for unobstructed passage (clean injection bores with a 0.5 mm drill, if required).

Check jet line-up. Install all parts.

8 Remove holddown (34), float (32) with float needle valve.

9 Pull out closing plug for intake port (suction duct) of accelerating pump with self-made puller. Lift valve ball out of duct (e.g. welding wire with grease).

10 Clean float chamber and ducts (200, 203, 204, 187) with compressed air.

187   Vent bore

200   Intake port

203    Idle speed mixture ducts

204   Vacuum bore for controlling enrichment

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11 Clean feed bores (165) and reserve chambers (164) with compressed air.

164 Reserve chamber for bypass system stage II 165″ Feed bore for reserve chamber stage II

12 Check suction valve for leaks. For this purpose, install valve ball (5 mm steel ball). Fill float chamber with fuel. Slip suitable hose over suction duct (intake port), keep both delivery valves (arrow) closed, on carburetors with vent bore (187) also keep these bores closed and blow into hose. No or only indivi­dual air bubbles should come out of intake bore and enter float chamber.

In the event of leaks, knock lightly against suction valve seat with steel ball (5 mm dia.). Insert new steel ball and check once again for leaks. Then close intake port (suction duct).

187 Vent bore

Arrow = delivery valve

13 Check delivery valves for leaks. For this purpose, slip suitable hose over a delivery valve, keep other delivery valve closed, on carburetors with vent bore (187) keep this bore also closed and blow into hose. No or only individual air bubbles should come out of suction bore (200) and enter float chamber. Then check opposite delivery valve.

In the event of leaks, knock balls of delivery valves “lightly” against their seat.

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14 Check float level and adjust, if required. For this purpose, push connecting web (arrow) up to noticeable stop in downward direction and check float level with­out gasket.

To avoid measuring faults, make sure that the float shaft rests on base of housing during test.

Measuring float level with flat roof float

Measuring float level with hip roof float

Correct float level, if required, by rebending at speci­fied bending point (arrow).

15   Attach float needle with wire clip on float arm in such a manner that the open side of clip points in driving direction.

16    Install float (32), making sure that the float shaft rests on base of recesses. Insert holddown (34). Holddown should project slightly over parting surface. Rebend, if required.

17    Mount carburetor cover with new gasket.

18   Mount air filter.

19   Adjust idle speed (07.2-100).

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