Begin any troubleshooting procedure by defining the
symptoms as precisely as possible. Gather as much infor-
mation as possible to aid diagnosis. Never assume any-
thing and do not overlook the obvious. Make sure there is
fuel in the tank, and the fuel valve is in the on position.
Make sure the engine stop switch is in the run position and
the spark plug wires are attached to the spark plugs.
If a quick check does not reveal the problem, turn to the
troubleshooting procedures described in this chapter.
Identify the procedure that most closely describes the
symptoms, and perform the indicated tests.
In most cases, expensive and complicated test equip-
ment is not needed to determine whether repairs can be
performed at home. A few simple checks could prevent an
unnecessary repair charge. On the other hand, be realistic
and do not attempt repairs beyond your capabilities. Many
service departments will not take work that involves the
assembly of damaged or abused equipment. If they do, ex-
pect the cost to be high.
Refer to Tables 1-3, at the end of this chapter, for elec-
trical specifications and diagnostic trouble codes.
An engine needs three basics to run properly: correct
air/fuel mixture, compression and a spark at the right time.
If one basic requirement is missing, the engine will not
run. Refer to Figure 1 for four-stroke engine operating
principles.
Engine Fails to Start (Spark Test)
Perform the following spark test to determine if the ig-
nition system is operating properly:
CAUTION
Before removing the spark plugs in Step 1,
clean all dirt and debris away from the plug
base. Dirt that falls into the cylinder causes
rapid engine wear.
1. Disconnect the spark plug wire and remove the spark
plug as described in Chapter Three.
NOTE
A spark tester is a useful tool for testing
spark output. Figure 2 shows the Motion
Pro Ignition System Tester (part No.
08-0122). This tool is inserted in the spark
plug cap and its base is grounded against
the cylinder head. The tool’s air gap is ad
-
justable, and it allows the visual inspection
CycleTech
ENGINE OPERATING
REQUIREMENTS
ENGINE STARTING
Classic Cycles Technical Resources
SPORTSTER
TROUBLESHOOTING
MANUAL
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