Topic: back to electrical issues again

[evinrude7]

What you have to do is determine what voltage the regulator "sees" when the battery is reading any voltage above 14.5v.

how do i accomplish this? 

start the bike and crank it up to 3000 rpm.  check voltage on battery and record then connect the pos lead to the black wire on the regulator and neg lead ground on the regulator and take that reading?

[TwoTired]

Yes, if you only have one meter you need to make a comparative reading under the same operating conditions.

Harbor Freight kept giving me DMMs for free.  I must have 10 of them stashed here and there.

[evinrude7]

i haven't tested to find out what the vreg sees when the battery is reading too high voltage but i did take the ignition switch off the bike to clean up the contacts in there thinking this could be the cause of my issue.  as i was taking it apart i noticed the brown wire up near the boot had a nick in it.  covered that up with electrical tape (all i had at the time).  bought some spiral wire covering and wrapped those wires.  the original wire sheathing had disintegrated.  i believe the reason for the nick in the wire was because a PO put low handle bars on the bike and the ignition switch wires were mashed on the edge of the fork top bolt.  after reassembling the ign switch i installed it back on the bike but i put a spacer on the bolt under the ign switch bracket to raise it from bottoming out on the fork bolt.  this should help until i order a new set of stock bars.  tomorrow i'll run more electrical tests to see if this sorted my issue. 

note: be really careful if you decide you want to clean up your ignition switch.  once you start to open it up and take it apart it's easy to have the springs and ball bearings shoot out when you get to the indexing part of the switch (the click you get from turning the key to an option on the switch is the result of ball bearings being pushed by springs into notches inside the unit).  i was on the kitchen floor more than once searching for ball bearings and springs.  i actually lost one spring.  found a click type ball point pen and scavenged the spring out of it.  cut it to size and it worked fine.  switch is like new.     

[evinrude7]

Yes, if you only have one meter you need to make a comparative reading under the same operating conditions.

Harbor Freight kept giving me DMMs for free.  I must have 10 of them stashed here and there.

TT, 12.2 v on the black and ground of vreg @ 3000 rpm/13.1 v at the battery terminals @ 3000 rpm

when i say on the black and ground of vreg i mean in the photo below.

i did rev the motor up above 4000 rpm and got numbers in the 15v + range at the battery terminals.

[calj737]

Thats an indication that there's an unusual amount of resistance on the BLACK circuit that is causing the VREG to see a lower voltage than the battery actually has, thus sending too much voltage to the battery.

Perhaps TT has a different viewpoint, but it is my opinion that you need to begin to trace the BLACK circuit back towards the key, measuring the resistance and locate the source of the nearly 2 volts of loss (through resistance).

The BLACK circuit comes from the KEY, gets power from RED when the key is switched to ON, then the BLACK provides power to the handlebar, idiot lights, and back towards the VREG. Look carefully at the stock wiring diagram to see the connectors that are in between the VREG and key that should be inspected.

[evinrude7]

Thats an indication that there's an unusual amount of resistance on the BLACK circuit that is causing the VREG to see a lower voltage than the battery actually has, thus sending too much voltage to the battery.

Perhaps TT has a different viewpoint, but it is my opinion that you need to begin to trace the BLACK circuit back towards the key, measuring the resistance and locate the source of the nearly 2 volts of loss (through resistance).

The BLACK circuit comes from the KEY, gets power from RED when the key is switched to ON, then the BLACK provides power to the handlebar, idiot lights, and back towards the VREG. Look carefully at the stock wiring diagram to see the connectors that are in between the VREG and key that should be inspected.

i can do that.  let me ask this.  should i be checking any off shoot of the BLACK wire between the ignition switch and the vreg?  for example: the rear brake switch is an off shoot of that BLACK line.  the front brake switch, the start button, etc...  would any of those cause the loss?  or is it directly a result of a problem between the ignition switch and the vreg? 

[TwoTired]

So, your bike is lying to the Vreg.  It's telling the Vreg that the battery is at 12.2V, and the vreg rightly thinks that is a low battery condition and unleashes all the wild devils in the alternator to correct the situation.

As Calj surmises, you have a bike wiring distribution problem.  So, what's the bike again?  76 CB750K, K6?  Is the wiring stock?  Assuming so, use the the wire diagram to follow the voltage from the Battery POS terminal to the Black wire output distribution out of the key switch, cause you are losing nearly a volt through that path.  It's likely worse with the lights on, but I guess you don't have a headlight switch.  All the connectors switches and fuse blocks are suspect.  And the more current being drawn by devices on the Black wire distribution, the more voltage loss you will have through resistive connections/contacts.  You can verify this by temporarily pulling the lighting fuses.  The Vdrop should improve.

CALJ's backward tracing is ok, too.  I just like to see the losses as they are encountered from the battery to the device.  Both can achieve the same result.

Cheers,

[evinrude7]

So, your bike is lying to the Vreg.  It's telling the Vreg that the battery is at 12.2V, and the vreg rightly thinks that is a low battery condition and unleashes all the wild devils in the alternator to correct the situation.

As Calj surmises, you have a bike wiring distribution problem.  So, what's the bike again?  76 CB750K, K6?  Is the wiring stock?  Assuming so, use the the wire diagram to follow the voltage from the Battery POS terminal to the Black wire output distribution out of the key switch, cause you are losing nearly a volt through that path.  It's likely worse with the lights on, but I guess you don't have a headlight switch.  All the connectors switches and fuse blocks are suspect.  And the more current being drawn by devices on the Black wire distribution, the more voltage loss you will have through resistive connections/contacts.  You can verify this by temporarily pulling the lighting fuses.  The Vdrop should improve.

CALJ's backward tracing is ok, too.  I just like to see the losses as they are encountered from the battery to the device.  Both can achieve the same result.

Cheers,

yes TT you have the bike correct and the wiring is stock although i have not gone through the wiring with a fine tooth comb.  i have a missing start button.  no aftermarket additions.  i'll go through the entire black wire distribution.  thanks for the help all. 

also, as calj mentions i should be checking resistance between these connections.  so set the dmm to ohms as i do when checking let's say the plug caps.  what reading should i be looking for?  0?

any suggestions on basic tools for the job?  i'm thinking deoxit, a few pointy brass brushes and some dielectric grease.

[calj737]

Check out Madmtnmotor's (Wilbur's) signature. He has a link with step-by-step guidance and tools for this task.

[evinrude7]

Check out Madmtnmotor's (Wilbur's) signature. He has a link with step-by-step guidance and tools for this task.

thanks for the tip calj.  i modified my post above with this.  "also, as calj mentions i should be checking resistance between these connections.  so set the dmm to ohms as i do when checking let's say the plug caps.  what reading should i be looking for?  0?

[calj737]

Well the plug caps aren't part of this problem. Their resistance should be near 5k Ohms if you're using R-type plug caps. Set your DMM to Ohms, and start checking all the circuits. I would suspect that somewhere within your harness you will find a PO "hacked" it up, spliced in some crappy twisted wires, or used cheap crimps. This lack of solid connection will show "continuity" but not near Zero resistance.

All corrosion, poorly attached connectors, splices, etc add some amount of resistance to that circuit. They have the be checked and repaired properly if you want a proper charging system. Worst case scenario, you'll have to unwrap the harness and inspect it end-to-end. Riverfever recently did this as part of a complete re-wire (I'm not suggest a re-wire) and discovered numerous botched splices that were driving him crazy with voltage drops at the coils. Had he not unwrapped the harness, he never would have found it.

It will take a couple of evenings, but to do it right, once, will provide years of trouble-free reliability. And save you purchasing new parts and batteries repeatedly 

[evinrude7]

Well the plug caps aren't part of this problem. Their resistance should be near 5k Ohms if you're using R-type plug caps. Set your DMM to Ohms, and start checking all the circuits. I would suspect that somewhere within your harness you will find a PO "hacked" it up, spliced in some crappy twisted wires, or used cheap crimps. This lack of solid connection will show "continuity" but not near Zero resistance.

i understand the plug caps are not part of this issue.  i'm ignorant but not that dense.     my point was the procedure is the same.  correct? 

[calj737]

Yes, DMM to Ohms. Either meter probe at either end of the plug cap, in contact with the metal crimp inside.

[TwoTired]

The standard dvm isn't the best tool for measuring small ohms values.  A milliohm meter is a far better tool for that.

But, your standard dvm is pretty good at determining small voltage values.  If you recall ohms law E = I x R.   So, with a circuit that has current flowing, resistance will directly effect the voltage flowing through it.  And, the more current flowing the greater effect resistance will have on the voltage drop.

Your measurements have already shown drops of 1v or more.  So, your circuit has the current flowing for your test voltmeter to find small resistance drops.  Here is a suggested test process:
Clip your negative dvm lead to the battery negative.
Place your pos meter lead on the green connection to your regulator.  The meter reads directly how much voltage is lost between those two test lead positions.  The only reason for that v lost is unwanted resistance in pathway connections, and the resistance of the wires themselves.  Ideally, it would be zero.  But, that's a physical impossibility.  So, we settle for very low values, in the order of .1v (or less).  If you have larger numbers than that, then you can "walk" the pos probe back along the physical path toward the battery Neg terminal, and note where there is a big numerical jump, inferring a large resisteive element has been located.
The same process can be performed on the battery positive distribution path.  Clip one lead/meter probe to the battery POS terminal, and the other on a black wire ( at the vreg, for example).  The meter will read directly the voltage differrence (Vlost) between its probe points and infer the magnitude of resistance between them. Again, you can "probe walk" along the physical path between probes, to find the largest drops along the path, and address the corrosion, oxidation, or otherwise poor connectivity issues.
Just remember that the voltmeter registers the potential difference between its probe tips.  So, if you suspect the key switch, for example place one probe on the red connection and the other on the Black connection, activate the circuit and read directly what v drop occurs within the key switch. But, recall that the magnitude of the V drop will directly proportional to the current flowing through it.  Even a faulty switch won't show a drop if there are no current loads passing through it.

The physical path is revealed by the wire diagram, btw.
An aberration to make note of, is the voltage loss of a depleting battery, which must not be confused with a resistance loss in circuit.  A battery charger, or other power supply can be used in conjunction with, or in place, of the battery for test purposes.  The bike's alternator can be used, too.  But, you should have a fan to cool the motor during "chase" procedures.

Hope this helps.  I feel this procedure is more definitive than chasing ohms with a standard DVM.

Cheers,

[BomberMann650]

It's worth noting, the solid state OMP vregs are cable of putting out 17v of battery melting power!  Iirc, the instructions (included with purchase) strongly suggest the voltage adjustment to be set at while running 5k rpm.

Any luck tracking down the other gremlins? 

[evinrude7]

It's worth noting, the solid state OMP vregs are cable of putting out 17v of battery melting power!  Iirc, the instructions (included with purchase) strongly suggest the voltage adjustment to be set at while running 5k rpm.

Any luck tracking down the other gremlins? 

The standard dvm isn't the best tool for measuring small ohms values.  A milliohm meter is a far better tool for that.

But, your standard dvm is pretty good at determining small voltage values.  If you recall ohms law E = I x R.   So, with a circuit that has current flowing, resistance will directly effect the voltage flowing through it.  And, the more current flowing the greater effect resistance will have on the voltage drop.

Your measurements have already shown drops of 1v or more.  So, your circuit has the current flowing for your test voltmeter to find small resistance drops.  Here is a suggested test process:
Clip your negative dvm lead to the battery negative.
Place your pos meter lead on the green connection to your regulator.  The meter reads directly how much voltage is lost between those two test lead positions.  The only reason for that v lost is unwanted resistance in pathway connections, and the resistance of the wires themselves.  Ideally, it would be zero.  But, that's a physical impossibility.  So, we settle for very low values, in the order of .1v (or less).  If you have larger numbers than that, then you can "walk" the pos probe back along the physical path toward the battery Neg terminal, and note where there is a big numerical jump, inferring a large resisteive element has been located.
The same process can be performed on the battery positive distribution path.  Clip one lead/meter probe to the battery POS terminal, and the other on a black wire ( at the vreg, for example).  The meter will read directly the voltage differrence (Vlost) between its probe points and infer the magnitude of resistance between them. Again, you can "probe walk" along the physical path between probes, to find the largest drops along the path, and address the corrosion, oxidation, or otherwise poor connectivity issues.
Just remember that the voltmeter registers the potential difference between its probe tips.  So, if you suspect the key switch, for example place one probe on the red connection and the other on the Black connection, activate the circuit and read directly what v drop occurs within the key switch. But, recall that the magnitude of the V drop will directly proportional to the current flowing through it.  Even a faulty switch won't show a drop if there are no current loads passing through it.

The physical path is revealed by the wire diagram, btw.
An aberration to make note of, is the voltage loss of a depleting battery, which must not be confused with a resistance loss in circuit.  A battery charger, or other power supply can be used in conjunction with, or in place, of the battery for test purposes.  The bike's alternator can be used, too.  But, you should have a fan to cool the motor during "chase" procedures.

Hope this helps.  I feel this procedure is more definitive than chasing ohms with a standard DVM.

Cheers,

thanks for the info and needed lesson TT. 

haven't found it yet bomber.  pretty sure it wasn't the front brake switch or the ignition switch.  just replaced the sh!t connections to the frt brake switch and took apart the ign switch the other night, cleaned it all up.  looks and works like new.  i started the bike and rev'd to 4000 rpm, showed 16 volts just now.  i have not tried to chase for voltage loss yet.  got home a little while ago and i'm spelling my wife from the kids; but they go to bed in T-minus 37 minutes. 

[BomberMann650]

Have you turned the white nib nob on the vreg counter clockwise yet?

[evinrude7]

Have you turned the white nib nob on the vreg counter clockwise yet?

yes.  not changing the voltage. 

[calj737]

Have you turned the white nib nob on the vreg counter clockwise yet?

yes.  not changing the voltage.

This approach is backwards: you would adjust the VREG up when the harness reads 12.xV or more, but the VREG is throttling the voltage to the battery. Your issue is the reverse; the harness is not passing full voltage therefore the VREG is supplying too much. Adjusting the VREG down at this point is masking the real issue and will ultimately lead to a problem.

Continue the trace as TT recommended until you find it. You'll be much happier. And you won't need to monkey with the VREG all Willy-nilly.

[evinrude7]

Have you turned the white nib nob on the vreg counter clockwise yet?

yes.  not changing the voltage.

This approach is backwards: you would adjust the VREG up when the harness reads 12.xV or more, but the VREG is throttling the voltage to the battery. Your issue is the reverse; the harness is not passing full voltage therefore the VREG is supplying too much. Adjusting the VREG down at this point is masking the real issue and will ultimately lead to a problem.

Continue the trace as TT recommended until you find it. You'll be much happier. And you won't need to monkey with the VREG all Willy-nilly.

checking ohms between the dmm leads i got .4 as a baseline.

with ign switch disconnected, in the off position, no key in it -  i tested each color wire from one end in the connecting block to where it connects to the ign switch.  black at block to black at switch. brown, brown with white stripe, and red.  each one showed .4 except for the brown which showed .5.

disconnected, with key in and turned to on.  got .4 between the black and red.  there is also a jumper from the red with another short red wire.  .4 from black to that jumper.

[TwoTired]

Are you subtracting the meter's baseline reading from the measurement reading?

[evinrude7]

Are you subtracting the meter's baseline reading from the measurement reading?

not sure i'm following you TT.  what it means to me is i have .4 ohms when i touch the meter leads together and i have .4 ohms when i check all the wires.  to me that's ZERO. 

[TwoTired]

Are you subtracting the meter's baseline reading from the measurement reading?

not sure i'm following you TT.  what it means to me is i have .4 ohms when i touch the meter leads together and i have .4 ohms when i check all the wires.  to me that's ZERO. 

That's the correct procedure for ohms measurement.   Trouble is, you haven't found where the voltage loss is occurring yet.

info:
A little math and ohms law.

E (volts) = I (current) X R (resistance)
a 0.1 ohm resistance will drop 1 volt with a current through it of 10 Amps.  0.05 ohms will drop 0.5V with a  10 amp current flowing through it.

Lower currents...
a 0.1 ohm resistance will drop 0.1 volt with a current through it of 1 Amps.  0.05 ohms will drop 0.05V with 1 amp current flowing through it.

As you can see, current has a way of magnifying voltage losses.  The current used by the DVM is very very tiny. It probably has a spec in the manual that came with it.

Finally, with zero current even very large resistances will drop NO voltage.

Keep going, you'll get it fixed eventually.  And have satisfaction afterwards.

Cheers,

[evinrude7]

very good.  i guess i was simply showing that the ign switch wasn't to blame.  thank you again for the info.  i know i need to learn this stuff. 

[calj737]

very good.  i guess i was simply showing that the ign switch wasn't to blame.  thank you again for the info.  i know i need to learn this stuff.

And there is no better mentor than TwoTired-San