Elusive volt

[Guest]

Greetings,

Readings with the key in the "on" position:

With the battery charged, voltmeter reads 13.31v at the battery posts.

Using voltmeter at the negative post of either coil, I lose 1 volt.

Disconnecting the 4 wire connector at the igniter, the missing 1 volt returns to the coil(s).

There is continuity at all 4 wires in the connector to the igniter, even if I wiggle the connector and wires.

Using the voltmeter (set to ohm's) in an attempt to duplicate the instructions in the factory shop manual, I don't get the spark/no spark of cylinders 3 and 4. Wrong kind of (ohm) meter?

To further confuse the situation, with everything connected, the motorcycle does run. All four plugs have healthy spark(s).

Is this a possible sign of regulator/rectifier or stator malfunction?

In reference to the Dynatek S ignition, does the module replace the unit under the ignition cover AND the ignitor?

Thank you for your time in solving this mystery.

[2whldreams]

Model/forgot

The above question is in reference to a 1982 GS1100E 4 valve.

Thanks again.

[terrylee]

probably need to clean the inside of the ignition switch. The bottom will come off and you'll see the wire connections inside. you can take it apart and clean it up inside and clean all wire connections. If you haven't done so I would clean all the elec. connections on the entire bike. terrylee

[Steve]

Is that 13.31 volts with the engine running or off?

If it's running, how are you disconnecting the ignitor plug and expecting the same voltage (because the engine stops)?

If that is with the engine off, that battery is overcharged. That's OK, though, just measure the battery, verify it's still 13.31, measure your coil at 12.31, THEN, ... go back to the battery to see if it's still at 13.31.

It is normal for a battery to lose a bit of voltage while the ignition key is on and the bike is not running. It is quite possible for it to lose a full volt from an overcharged battery (possibly very recently removed from a charger) by the time you get the leads onto the coil connector. That is why I suggest going back to the battery for another test to see if it's still dropping or has stabilized.

.

[posplayr]

It really is not clear what you are measuring or even what you are trying to accomplish. Steve thinks you are trying to measure the battery voltage drop when the key is on but is seems more like you are trying to measure the voltage drop at the low side of the coil. if there is a factory procedure follow that.
If you could clarify what you are trying to do someone could probably provide guidance on how to perform that test.

[Steve]

It really is not clear what you are measuring or even what you are trying to accomplish. Steve thinks you are trying to measure the battery voltage drop when the key is on but is seems more like you are trying to measure the voltage drop at the low side of the coil. if there is a factory procedure follow that.
If you could clarify what you are trying to do someone could probably provide guidance on how to perform that test.

No, I realize that he is trying to measure the drop at the coil, but if the bike is not running, and the battery is a bit "iffy", in the time it takes to go from a battery voltage reading to a coil voltage reading, that battery could lose a volt. To confirm that suspicion, do another battery test right after the coil test. If the battery voltage is right were it was in the first measurement, the drop at the coil is, indeed, a drop at the coil. However, if the battery voltage has dropped, you now have another variable to track down.

.

[posplayr]

No, I realize that he is trying to measure the drop at the coil, but if the bike is not running, and the battery is a bit "iffy", in the time it takes to go from a battery voltage reading to a coil voltage reading, that battery could lose a volt. To confirm that suspicion, do another battery test right after the coil test. If the battery voltage is right were it was in the first measurement, the drop at the coil is, indeed, a drop at the coil. However, if the battery voltage has dropped, you now have another variable to track down.

.

I understand all that, but are you sure you know what he is trying to do? If he is then why is he measuring the coil voltage at the negative side and checking the ignitor? I give up with guessing

I'm pretty sure what ever he is trying to do he is not doing a very good job of it.

[Steve]

I missed the part where he was measuring the negative post.

.

[Gorminrider]

2whldreams, I get the feeling the bike is not running too. Don't know why-weird!

So the bike runs great? or doesn't run? Perhaps that is what's missing? What is the problem?

...reads 13.31v

Is this a possible sign of regulator/rectifier or stator malfunction?

yes, if bike is running faster than an idle.
I see that you are interested in the voltage drop and that's great! Lots of stuff online about this.Basically every single circuit is a (edit) serial sum of resistances and every resistance uses current and voltage. This includes wire and connections. The voltage drop across a component indicates how much of the sum it is "using" and indeed can find a high-resistance voltage drop where none should be! ie:bad connectors,burned wire, shorts, Many Things... but don't forget ignition is not just about voltage drops.It's a bit of a special case, unlike lighting,switches,relays- yes, of course you can test the VD and resistance statically IF you separate it from the modifiers. You see, the coils are charged and discharged as the bike is running so a static test can give some odd results in resistance and voltage with a multimeter, especially where capacitors are somewhere in the circuit.
BUt I'm wingin it here too. Take the above with a grain of salt...

Using the voltmeter (set to ohm's) in an attempt to duplicate the instructions in the factory shop manual, I don't get the spark/no spark of cylinders 3 and 4. Wrong kind of (ohm) meter?

..therefore,as I explained sort of,I suggest you Disconnect the coil to test it's resistances...

otherwise,I don't have the manual.I'm lost here as to what is wanted to fix-can you explain?

To further confuse the situation, with everything connected, the motorcycle does run. All four plugs have healthy spark(s).

again, what is the problem you are trying to solve?

In reference to the Dynatek S ignition, does the module replace the unit under the ignition cover AND the ignitor?

someone else?

[2whldreams]

While checking the general health of the electrical system, curiosity created an opportunity to move the probes of the voltmeter around and I was able to observe the afore mentioned scenario.

Engine off, key in the "on" position, black probe (voltmeter) on negative post of the battery. Move the red probe from the positive battery post to the negative post of the coil, and lose a volt.

Disconnect the 4 wire connector to the igniter, gain a volt.

It may mean absolutely nothing and is just a characteristic of the wiring layout, as Posplayr suggests.

Just for future reference, does the Dynatec S Ignition System replace the assembly under the ignition cover AND the igniter.

Thank you all for your assistance.

[Steve]

Measuring on the negative side of the coil (the side that goes to the ignitor) is not the proper place to measure coil voltage. You should measure at the positive side of the coil.

The negative side is the side that is switched by the ignitor, so any voltage there would depend on current going through the coil. Voltage on the positive side should not have gone through any voltage drops, and should be virtually the same as battery voltage.

When you disconnected the ignitor, you stopped any current flow, so everything between that connector and the battery should show exactly the same voltage.

.

[jabcb]

Just for future reference, does the Dynatec S Ignition System replace the assembly under the ignition cover AND the igniter.

Yes, the Dyna S replaces the ignitor & signal generator. It uses the stock mechanical advance.

[terrylee]

Sorry read it wrong, thought he said ignition that he unplugged. terrylee

[posplayr]

While checking the general health of the electrical system, curiosity created an opportunity to move the probes of the voltmeter around and I was able to observe the afore mentioned scenario.

Engine off, key in the "on" position, black probe (voltmeter) on negative post of the battery. Move the red probe from the positive battery post to the negative post of the coil, and lose a volt.

Disconnect the 4 wire connector to the igniter, gain a volt.

It may mean absolutely nothing and is just a characteristic of the wiring layout, as Posplayr suggests.

Just for future reference, does the Dynatec S Ignition System replace the assembly under the ignition cover AND the igniter.

Thank you all for your assistance.

I guess you are simply saying it is an observation with no specific objective. Can you give the full voltage you are measuring At
Battery(+)
Coil (+)
Coil (-)
And we can probably explain what you are seeing. The circuit you are observing includes battery, ignition switch and other parts in the harness that drop voltages as well as shares current paths with circuits other than the ignition. The coils are pretty simple device but the ignitor turns on and off so that adds a complexity as well.
Keep the negative lead of the VOM on the negative post of the battery.

After doing that you could also check your charging system with "Quick Test" see my signature for a link.

[Sci85]

Interesting. I have never done this so I thought I would try it too. Battery on, headlight on, engine off, I have 11.88 at the battery. Move the the positive probe over to the o/w wire on the coil and I initially have 9.91v. After several seconds, I noticed the voltage climbs. After about a minute it was up to 10.00v. I think I may have some crummy wire and/or connections right? Bike seems to fire ok though. Recommendations?