1.
Check the
battery. Battery voltage
should be:
o - 12.4-12.8V for a conventional battery (the clear
type with liquid);
o 12.6-12.8V for the newer MF batteries;
o 12.8-13.2V for even newer Gel or AGM batteries.
A defective battery cannot be recharged.
o Load test it if necessary. To load test it you
can use your motorcycle's starter by disabling the ignition and cranking it for
15 seconds. In the end, that battery should still be at least 10.5 volts.
2.
Check the charging or
rectified voltage: 13-15V for 12-volt systems. Rev the engine to mid
range a few times & record the highest value.
o If the charging voltage is too high, this will damage
any battery.
ยง
The possible causes
are:
1.
The regulator
2.
The voltage sensing
lead.
o If the charging voltage is too low, proceed to step
3.
3.
Check the
stator output. Most
street motorcycles use a 3 phase charging system. Most with a magnetized
rotor (PMS), some with an electromagnetic rotor (EMS).
o For the first kind, unplug the stator coupler &
connect your voltmeter in VAC @ each set of stator windings running the bike @
idle. You should get about 15VAC (3 times).
o For the Electromagnet System type, keep the coupler
connected & do the same thing. You should get at least 9VAC.
4.
If this test is
inconclusive, check the
resistance of your stator (.2-2.5 Ohms). And (very important) verify no
connection to ground when unplugged.
o For the EMS kind you'll also need to check the
resistance of the field coil (2-10 Ohms) and also make sure it doesn't have a
connection to ground (when unplugged). That field coil will need to have
battery power to it (when turning the key on) for the electromagnet to
function. It will also need a good regulation (usually on the negative
side) before the ground. The regulator can be checked, by simply bypassing
it. When doing so, the charging voltage will rise (careful, it may rise
too much) if defective.
5.
If the stator
output is OK:
o Check the rectifier
o Check the pos connection of the
rectifier to the battery positive.
o Check the neg connection of the rectifier to the
battery negative.
6.
If all of these are OK:
o See if the idle is not too low.
o Check that there are no components that stay powered
with the key off.
o Verify that there are not too many optional
electrical devices.
o Last but not least, is the bike being ridden long
enough after each engine start?
7.
On a Permanent Magnet
System, the regulator cannot be checked so replacing it is the last solution.
If this doesn't help you or doesn't give you enough details, leave me a message; I'll be glad to guide you.