AJS Highway Star 125, Owner'S Manual, Page: 34 / 61

30
SPARK PLUGS, continued
Whilst checking each spark plug, note the colour of the
electrodes. Mild brown indicates all is normal and
well. Black indicates that the engine is running too
rich. This could be caused by a dirty air filter or the
jet/s may be too big. A whitish colour electrode
indicates the engine is running weak. This could be
caused by a fuel blockage or an air leak.
Seek professional advice from your dealer before
making changes.
If the colour of the spark plug electrodes are black
or white after normal use, seek professional
advice from your dealer.
Brown indicates normal conditions.
CAUTION!
1) Install a new spark plug by hand until it seats –
(fig 1) a length of rubber tubing pushed over the
insulator can be a useful aid for plug installation
where access is difficult.
2)Tighten to the specified torque setting: 12Nm.
3) Do not use a power tool to tighten the spark
plug.
4) Be sure not to drop foreign objects into the
open plug hole when the plug is removed.
5) Smear a light coat of copper grease onto the
threads to aid removal later.
6) Take care not to cross the threads when
inserting the plug. Start it off by hand.
7) The spark plug for this model has been chosen
carefully. Do not change it for a different type.
CAUTION!
1