A.J.S. 3.46 H.P., Руководство пользователя

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When the machine is despatched from the Factory the Carburettor has been correctly
set, but if the machine is used under varying atmospheric conditions, slight adjustments
may be necessary. In the first case if starting is difficult and the Engine refuses to " idle "
evenly, slowly screw the Pilot Air Adjuster inwards, but if on the other hand the Engine is
inclined to " eight stroke " at slow speeds, screw the Pilot Air Adjuster out until this disappears,
A point worth mentioning about starting is that the Throttle Stop (illustration) should be set
so as to lift the Throttle Slide slightly off its seat, the twist grip can then be left in the
" closed " position when starting the Engine. The next adjustment is carried out by fitting
a throttle Valve with a different cut-away. If when opening the Throttle spitting back
through the Carburettor, or misfiring occurs, this indicates a weak mixture. To correct this
fit a Throttle Valve with a smaller cut-away.
Black smoke from the exhaust or "eight stroking" at low-intermediate Throttle
openings indicates richness, fit a Throttle slide with a larger cut-away.
As a guidance each throttle Valve is stamped with two numbers. The first indicating
the type of Carburettor, and the latter indicating the amount cut-away from the intake side
of the valve in sixteenths of an inch. Thus—6/4, is a type 6 Valve with ¼ in. cut-away.
The necessity for alteration to the needle position may be checked in the following
way; Start the Engine and open the air lever to its fullest extent, open Throttle control
half way and notice whether the exhaust note is crisp and the Engine lively, then close air
lever slightly, if this results in increased Engine speed raise the needle to the next position
in the throttle valve. On the other hand, if the Engine speed does not increase when the air
lever is closed to about half way and the throttle opening increased, or if any tendency to
" eight stroke " occurs, then lower the needle to the next position in the throttle slide. To
alter the needle position pull away the small spring clip locating the needle in the Throttle
Valve and afterwards force this home again. For a Semi-Automatic setting where the Rider
intends to use the Air Lever judiciously and studies extreme economy, lower the needle one
groove further after carrying out this range of tests. For speed work, the Main Jet size may
be increased by 10% as the air lever should always be full open on full throttle openings.
STANDARD CARBURETTOR SETTING
Main Jet
size.
33/7 160
33/10 200
Needle
position.
3
3
Cut away.
6/4
6/5
RACING CARBURETTOR SETTING
For 59/50 Petrol Benzol and Engine Compression ratio 7,5 to 1.
Main Jet
size.
33/7 52
33/10 58
Cut away.
4/5
4/5
Bore size.
1
z
1
x
Carb.
Type No.
N.M.8617
N.O.3131
For Discol R.D.1 Fuel, and Engine Compression ratio 11 to 1.
Main Jet
Size,
33/7 55
33/10 65
Valve No.
12
12
Bore Size.
1.06
1.18
Carb.
Type No.
N.M.7091
M.D.992I
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