is there a way to test a capacitor

[jolo9534]

hey guys so i was working on the wiring for my xs. as usual i stared the bike up just to make sure it works. then i started in on the wiring. after a few hours of moving things here and there i finally finished up. went to start the bike and nothing. since its a kick start only i have a pma and a capactior. now after a few mins of checking around i noticed when i went to grab the capacitor something rattled inside. i assume that its no good anymore. is there a way to test it. i haven't had it very long. the capacitor only had mins of use on it. thanks

 

[wrenchjohns]

Well, back in the day, we'ed put put it in the plug wire of a running engine, carefully remove and toss it to a buddy. If it was good it would shock the s__t out of him. Now that age has arrived, it might kill him, so I really don't recommend this method. john

 

[retiredgentleman]

You could connect a 12 volt motorcycle, or car battery, to the capacitor for 15 or 20 seconds, then disconnect it. Next, use a small 12 volt bulb with some wire leads and connect it to the capacitor terminals. If the capacitor has charged up, the bulb should light for perhaps a few seconds and then go out as the cap discharges through the bulb.

 

[TwoManyXS1Bs]

A simple shop test uses the multimeter.
First, short the capacitor, temporary touch both contacts with a screwdriver shank, or whatever.
Then, set the multimeter to resistance test.
Connect to capacitor.
You should see the resistance start low, then progress to infinity.
This indicates charging of the capacitor, to fully charged.
Disconnect leads, switch multimeter to voltage test.
Connect to capacitor.
You should see a voltage. Watch to see if it drops rapidly.
This indicates leakage...

 

[jolo9534]

A simple shop test uses the multimeter.
First, short the capacitor, temporary touch both contacts with a screwdriver shank, or whatever.
Then, set the multimeter to resistance test.
Connect to capacitor.
You should see the resistance start low, then progress to infinity.
This indicates charging of the capacitor, to fully charged.
Disconnect leads, switch multimeter to voltage test.
Connect to capacitor.
You should see a voltage. Watch to see if it drops rapidly.
This indicates leakage...

is the capacitor hooked up to a battery?, i dont see how the resistance would start low then progress up if i shorted it. or how it would have any voltage

 

[jolo9534]

You could connect a 12 volt motorcycle, or car battery, to the capacitor for 15 or 20 seconds, then disconnect it. Next, use a small 12 volt bulb with some wire leads and connect it to the capacitor terminals. If the capacitor has charged up, the bulb should light for perhaps a few seconds and then go out as the cap discharges through the bulb.

ill try that tomorrow. thanks

 

[retiredgentleman]

is the capacitor hooked up to a battery?, i dont see how the resistance would start low then progress up if i shorted it. or how it would have any voltage

2M's test is a quick easy way to test capacitors. Is there a battery..................yes there is. Its the battery inside the VOM that is used during resistance testing. The resistance of the capacitor is very low at first because it has no charge, and looks like a short circuit to the VOM. As the current from the VOM rushes into the low resistance, the capacitor charges up to equal the battery voltage of the VOM. As the charge on the capacitor (voltage) starts to reach the same as the VOM voltage, the current drops off and the resistance goes very high.

 

[queenslegs]

Well, back in the day, we'ed put put it in the plug wire of a running engine, carefully remove and toss it to a buddy. If it was good it would shock the s__t out of him. Now that age has arrived, it might kill him, so I really don't recommend this method. john

Reminds of the time they told me the scope was floating..... Capacitive coupling my ass!

 

[jolo9534]

2M's test is a quick easy way to test capacitors. Is there a battery..................yes there is. Its the battery inside the VOM that is used during resistance testing. The resistance of the capacitor is very low at first because it has no charge, and looks like a short circuit to the VOM. As the current from the VOM rushes into the low resistance, the capacitor charges up to equal the battery voltage of the VOM. As the charge on the capacitor (voltage) starts to reach the same as the VOM voltage, the current drops off and the resistance goes very high.

ahhh i see, ill have to check that out tomorrow, but it turns out, it was a faulty ignition switch. thanks for the input guys