Ignition Timing - Honda CB350 Repair Manual

TUNE—UP
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casionally. This minimizes wear and en—
sures that the timing will remain accurate
for a longer period. A worn heel will re—
tard the timing.
2. A small dab of grease (high melting
point, if possible) should be applied to
the lubricator wick so that the lubricator
can distribute it onto the breaker cam. A
drop of engine oil should be applied to
the pivot point.
3. In both cases it is imperative that
care be taken to keep the lubricant away
from the points contact surface.
4. The lubricating wick should be ad—
justed so that it just contacts the breaker
cam.
5. If the wick is missing the grease can
be applied sparingly to the cam itself.
Ignition Timing
On all breaker point equipped engines,
the spark plug fires at the instant the
points open. The purpose ofignition tim—
ing, —then, is to adjust the points so
that they will open at the correct time rel—
ative to the piston position, which is
usually expressed in millimeters before
top dead center (BTDC) or in degrees of
crankshaft rotation BTDC.
To properly time the engine, a device
is therefore needed to determine the pis—
ton position, and another to find when
the points open.
The alternator rotor is equipped with
marks which indicate piston position
when aligned with the stationary mark on
the stator. "LT" is the left piston at top
dead center, while "T" is the right piston
at top dead center. "LF" is the firing
point (without spark advance) for the left
cylinder; "F" indicates the firing point
for the right cylinder. An additional pair
of marks for each cylinder indicates the
firing point when the timing is fully ad—
vanced.
The moment of point opening can be
checked in several ways.
By far the easiest and most accurate
method ofignition timing is the use ofan
automotive—type strobe light. This can be
used on all models, and its chief advan—
tage is that it allows the timing to be set at
full advance, where it is most important.
If a strobe light is available, refer to "Dy—
namic Timing" which follows.
Ifa strobe light is not available, timing
can be accomplished using the rotor
marks along with a test or continuity
light, or an ohmmeter.
2
1
14 Volt Bulb
Continuity light with self—contained power source
A continuity light can be constructed
according to theillustration, consisting of
a battery, bulb, and two leads. The bat—
tery can be a flashlight dry cell, or a 6 or
12—volt battery with a suitable bulb. If
this type ofself—powered tester is used,
the motorcycle's ignition is left OFF
when checking timing. If the connections
are correct, the bulb will go out when the
points start to open.
12—Volt Bulb
s
Alligator Clips
A simple test light
A second type oftester need only be a
bulb of system voltage (12v) with two
leads attached. A headlight bulb can be
used. This set—up requires that the motor—
cycle's ignition be on when checking the
timing. When the points begin to open
the light will go on.
An ohmmeter can also be used. Con—
nect one lead to the points primary wire
terminal and the other to a ground such