Norton Commando Workshop Manual

## Carburetor

# E

### SECTION E3

### CARBURETOR DISMANTLING

The carburetor as detached from the motorcycle is partially dismantled, in that the mixing chamber top and both throttle and air slides have been removed. If the top and slides are to be removed from the cables, proceed as follows:
1 | Lift the throttle return spring, note the groove in the needle to which the clip is engaged then remove the clip. Collect the needle.
2 | Disengage the throttle cable nipple and collect the throttle valve.
3 | Lift the air valve cable and spring, disengage the cable nipple and collect the air valve.
4 | The top is now free to be lifted clear. Dismantling of parts from the mixing chamber should proceed as follows:
5 | Remove the two screws securing the float chamber to the carburetor body and collect the float chamber complete with float and float needle, also the joint washers.
6 | The float and float needle are manufactured from white nylon. Lift the float, float needle and float spindle clear for later examination and drain the float chamber.
7 | Remove the main jet, needle jet and pilot jet.

### SECTION E4

### EXAMINATION OF CARBURETOR PARTS

The following parts should be examined and replacements made where necessary:
Float: Check for leakage - fuel can be seen in the float
| if this condition exists. Check also that the float needle fits securely.
Float needle: Check for wear on the seating taper.
Main, needle and Pilot Jets: Examine for damage
| and blockage - never use wire to clear a blockage but instead use compressed air.

Throttle Valve: Remove any burrs and burnish
| carefully any scores. Deep scoring renders the valve unfit for re-use.
Throttle needle: Ensure the needle is not bent or
| worn badly on the taper. Check that the clip grooves are clear and "sharp".
Carburetor Body: Blow out all internal galleries with
| compressed air. Check that all threads are sound. Examine for excess wear on the throttle valve bore.
Pilot Air Screw: Check for wear on the taper.

### SECTION E5

### CARBURETOR REASSEMBLY

Assuming all parts are clean and in sound condition, commence reassembly as follows:
7 | Using new friction 'O' rings on both screws if the originals have deteriorated, refit the pilot air screw and throttle stop screw.
8 | Fit the needle jet to the jet holder and jet holder to the carburetor body.
9 | Fit the main jet.
10 | Position the float, with float needle and spindle, in the float bowl.
11 | If the original is damaged, fit a new float bowl joint washer ensuring it is the correct way round with the holes aligned to the jet passages in the bowl.
12 | Fit the complete float bowl and secure with the two screws and washers.
Where the originals have deteriorated, replace the 'O' ring in the mounting flange of both carburettors and couple the carburetors to the manifolds, securing with two nuts and plain washers for each instrument. Connect the balance pipe to both manifolds. If the air and throttle valves and mixing chamber tops have been detached from the control cables, they should be re-connected as follows:

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