o High engine temperature
o White spark plug (when removed for inspection)
NOTE: When inspecting the spark plug to evaluate jetting, a properly jetted
machine will produce a spark plug that is dry and light tan in color.
Environmental and altitude related mixture adjustments
NOTE: Before making any carburetor jetting changes verify that:
o You are using the proper fuel and oil
o The fuel is fresh and uncontaminated
o The oil and fuel have been mixed in the proper ratio
o The carburetor is clean (no plugged jets)
o The air filter is properly clean and oiled
o The float height is within proper specification (proper measuring technique
is described later in this section)
NOTE: Perform all jetting changes on a
motorcycle that has been warmed up to proper
operating temperature.
The carburetor on your Cobra motorcycle is
quite adjustable. Figure 49 shows its range of
adjustment and in particular what adjustable
component affects what range of operation
(specifically throttle position).
FUEL SCREW ADJUSTMENT: Adjust for throttle response
The air adjustment screw is located on the left side of the carburetor. It requires
the use of a small flat blade screw driver for adjustment. After adjusting for
proper throttle response, use the idle screw to adjust the desired idle speed.
NOTE:
If the air screw requires more than 3 turns out, replace the pilot jet for one that is
one size leaner (smaller number) then readjust the fuel screw.
IDLE ADJUSTMENT: Adjust for desired idle speed
The idle speed screw is located on the right side of the carburetor. It is hidden
behind the exhaust stinger pipe and is barely reachable with a screwdriver. To
raise the idle, turn the screw in, clockwise, (in 1/4 turn increments) and rev the
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