chestercheeto20022000
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- 22
- Location
- lynchburg va
i ran across this at a losi website using water to check head temp
Tuning the High-Speed Needle
To obtain the correct high-speed needle setting, start
the engine and drive your vehicle around for a minute
or two, applying full throttle frequently. Place a drop
of water on the cylinder head. If the water sizzles away
(evaporates immediately), the needle setting is too
lean. A correct needle setting will result in the water
evaporating after 3–5 seconds. If the water does not
evaporate, chances are good that the needle setting is
too rich. Lean the needle 1/16 of a turn and run the
engine again, adjusting the needle setting to get the
desired evaporation time.
Check the temperature each time you change
the needle mixture. Do not let the engine
overheat, as this will damage the engine.
Tuning the Low-Speed Needle
The low-speed needle (also referred to as the idle
mixture or idle needle) should be set after you’re
satisfied with the high-speed needle setting. After
achieving the proper operating temperature, reduce the
engine throttle to idle and pinch the fuel line with your
fingers close to the carb fuel inlet nipple. If the engine
dies immediately, the low-speed needle is set too lean.
If the rpm’s increase dramatically, the setting is too rich.
The ideal setting results in the rpm’s increasing just a
slight amount after pinching the fuel line.
Idle Stop Adjustment
The last setting to be made is the idle stop screw.
Turning this screw clockwise increases the idle speed,
whereas turning the screw counterclockwise will
make the engine idle at a lower speed. Ideally, the
engine should idle just fast enough to be reliable in
acceleration and transition from idle to full speed.
Avoid an idle speed that is too fast, as it will cause
damage to your clutch.
Tuning the High-Speed Needle
To obtain the correct high-speed needle setting, start
the engine and drive your vehicle around for a minute
or two, applying full throttle frequently. Place a drop
of water on the cylinder head. If the water sizzles away
(evaporates immediately), the needle setting is too
lean. A correct needle setting will result in the water
evaporating after 3–5 seconds. If the water does not
evaporate, chances are good that the needle setting is
too rich. Lean the needle 1/16 of a turn and run the
engine again, adjusting the needle setting to get the
desired evaporation time.
Check the temperature each time you change
the needle mixture. Do not let the engine
overheat, as this will damage the engine.
Tuning the Low-Speed Needle
The low-speed needle (also referred to as the idle
mixture or idle needle) should be set after you’re
satisfied with the high-speed needle setting. After
achieving the proper operating temperature, reduce the
engine throttle to idle and pinch the fuel line with your
fingers close to the carb fuel inlet nipple. If the engine
dies immediately, the low-speed needle is set too lean.
If the rpm’s increase dramatically, the setting is too rich.
The ideal setting results in the rpm’s increasing just a
slight amount after pinching the fuel line.
Idle Stop Adjustment
The last setting to be made is the idle stop screw.
Turning this screw clockwise increases the idle speed,
whereas turning the screw counterclockwise will
make the engine idle at a lower speed. Ideally, the
engine should idle just fast enough to be reliable in
acceleration and transition from idle to full speed.
Avoid an idle speed that is too fast, as it will cause
damage to your clutch.
