Author Topic: Electrical Odyssy: Now TORMENT [Updated]  (Read 11527 times)

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Offline burmashave

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Electrical Odyssy: Now TORMENT [Updated]
« on: August 02, 2008, 07:33:00 pm »
This is long; however, I wanted to provide some detail about how I got my bike from electrical weakling to smooth runner supporting a halogen headlight, Dyna 2k ignition and Dyna 3 ohm coils.



I've been battling the electrics on my '77 CB750K since I got it several years back. I should have known something was up when I realized that the previous owner had installed an on/off switch for the headlight. "Self," I said, "why would he do that?"

To make matters worse, I installed a halogen headlight, 3 ohm Dyna coils and a Dyna 2k ignition. The thing is, it usually ran just below maintaining a charge. Rides of about 100 miles were about max before going back to the charger at home.

Here are the steps I've taken to optimize the electrical system on my CB750:

Voltage Meter
Early on, I installed a Kuryakyn LED Battery Guage which I mounted unobtrusively just below the instrument light panel. It has been immensely useful, especially because I have needed to head home when voltage began to really drop off.



Interestingly, there is a peak voltage RPM for the bike around 3,700 RPM. Any lower, and the alternator is not producing maximum. Any higher, and the higher RPM's cause the coils to consume more voltage. Sometimes, riding was a fun game of keeping RPM's near 3,700.

Bench Testing
I bench tested all the components, following the Charging System Troubleshooting FAQ in addition to procedures in the shop manuals. The individual components checked out O.K. Even with the add-ons, it seemed I should have more voltage, and at any rate, if I wanted to keep the add-ons, I needed to find more voltage.

Shotgun Replacements
I replaced the regulator with a solid state one, and I replaced the rectifier just in case. The starter solenoid was fairly corroded, so I replaced that, too. I replaced the battery with a Yusa; however, I don't think any of this maintenance made much of a difference. (I wasn't really hopeful, anyway.) Besides, all had checked out O.K. on the bench. As all of these components looked original (except for the battery), I don't regret replacing them.

Contact Cleaning
Using a round file, bottled air, contact cleaner and contact lube, I cleaned all the electrical contacts I could put my hands to. I don't think I did a terribly good job, and it didn't make much difference.

Marker/Signal LED's
Next, I replaced the marker, signal and clock illumination lights with LED's. See my FAQ for Fitting LED Indicators. I tested it at the time; however, I've lost my numbers. At any rate, this change brought me just a bit more voltage. I didn't replace the brake light. At the time, I couldn't find one that was bright enough.



Wiring Harness Rebuild
I then rebuilt the wiring harness. Before I started, I created a Color Wiring Diagram in Vector Format. This made life much easier because I could work from a diagram of any size (I printed it to about 24"x14"). Check out the diagram if you have a '77 or '78 K; I also posted a large jpg format diagram.

Rebuilding the wiring harness took much longer than I planned because I did it in starts and stops and because I was absolutely picky. I soldered every connection except at the components, and I wrapped all solder joints with double-wall heat shrink tubing. I've soldered professionally, so I was picky about the solder joints.



To make things more fun, I didn't use electrical tape or cable wrap for the cables. Instead, I wrapped all bunches of two or more wires with heat shrink tubing. This meant that before each solder, I had to consider/cut/place both tubing for the joint plus tubing for the wires that would be cabled together. Plus, I had to do it without heating any tubing while soldering. The entire harness, end-to-end, is encased in heat shrink, except where wires protrude to the components. Oh, and this meant that everything had to be right the first time.



Some have suggested rebuilding a harness by doing it one wire at a time. I did it by marking all the wires with stick-on numbers, taking copious notes and cutting the old harness out entirely. With a larger diagram, it was easy to put matching numbers on each of the wires on the diagram. I built a new harness on the bench, using the old one to match up the cabling, and then installed it working from the electrics compartment out.

Given the problems with corrosion in the contacts of the standard fusebox, I followed somebody else's advice and replaced the fuses with automotive fuses. A changeover is pie because a standard slide terminal fits an auto fuse well.



When I got the whole thing done, I had gained about 0.5 to 0.7 volts! And man, oh man am I much more confident in the state of my electrical system.

By the way, I've used several butane soldering irons, but this Weller is far better than others I've used:



It's about twice as expensive as the others, but I feel it's worth it. I also use a second Weller with a "heat" tip for shrinking tubing.

LED Brake Light
A few weeks back, someone pointed me to the Luxeon LED. The Luxeon is better than the other LED's I've tried for the brake light; however, I think the original incandescent is a bit brighter. The Luxeon, like other LED's, is directional, so I had to add lights for the license plate. I used directional single LED's for the license light, and if I did it over, I would have used at least 3 or mebbe four bulbs instead of 2. The single LED's are dim.



Note that the LED's are directional and do not make use of the reflector, so there's no prob in running wires/bulbs over it.

The Luxeon isn't as low wattage as normal LED's. It draws 3 watts; however, the gain finally pushed my bike over the charging edge! I could ride and ride without the need to put it back on the charger when I got home.

HondaMan Resistor Set
I still needed to do some more work because I wasn't quite there yet. I didn't have insurance voltage (the bike wouldn't push the voltage above 12.75 volts). Ahhhhhh, then came the Hondaman Resistor Set for 3 Ohm Coils. After installing it I am getting over 13 volts at running speeds, always! It maintains 13 volts unless I spend mebbe 15 minutes in town, or if I run the high beam for more than a few minutes. Thanks HondaMan, that was the last piece of the puzzle.



As shown, the resistor set installs just behind the coils.

Woo Hoo! The Yellow Bomber is ready for long rides.

To Be Done
I've been wondering if a rewind for the stator and possibly for the coil this winter might help. Both check out on the bench, but I've wondered if mebbe the stator is producing less voltage after it heats up. I'll test this next.

Edit: 3 August
I just caught this recent thread about HID conversion for the headlight. I had looked into this some time back, but at the time, it didn't seem that the technology had matured enough for me to try it.

Edit: 4 August
BLAST! I thought I had it licked. But not so. See below.
« Last Edit: August 28, 2008, 06:44:50 am by burmashave »
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline GammaFlat

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Re: Electrical Odyssy: Complete!
« Reply #1 on: August 02, 2008, 08:08:25 pm »
I checked out the url on the bottom of your post - That is a fantastic color for that bike.  I have a '77 with 2 sets of covers and a couple tanks.  I can make it a chameleon :)  You've got a great example of a solid color - as opposed to "factory stripes" - I love that.  I may lean toward a black set and I'm not sure what other color....  :-\  I sure like your yellow.  ;)

The electrical work is great stuff to post on the forum.  I may wind up stepping outside of "stock" on one or more of my bikes as you did. 
K6
K7 
Suzuki GN400 - Ignition fixed!
03 KLR650 - Doesn't do anything very well but.. well.. does everything.

Offline burmashave

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Re: Electrical Odyssy: Complete!
« Reply #2 on: August 02, 2008, 08:14:41 pm »
That's funny. You're the second rider in a week to tell me that he likes the yellow. The previous owner painted it, and until now, I've not really liked it. I was thinking about painting it the stock maroon red for that year, but I'm considering repainting it yellow (the original sidecovers are broken, so I need to do some painting).
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

troppo

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Re: Electrical Odyssy: Complete!
« Reply #3 on: August 02, 2008, 08:31:15 pm »
Great post burma.
Explains things so well, and makes me think i should do something similar on my old girl

fuzzybutt

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Re: Electrical Odyssy: Complete!
« Reply #4 on: August 02, 2008, 09:59:19 pm »
is it possible to rewind the stator for better charging?

Offline burmashave

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Re: Electrical Odyssy: Complete!
« Reply #5 on: August 03, 2008, 05:05:44 am »
is it possible to rewind the stator for better charging?

Here's a Thread about Rewinding Stators. There are a few others as well.

I'm not looking to change the output volts/amps from stock. It's just that I still feel that something is not 100% right with my charging system, although it bench tests O.K. I'm wondering if mebbe some of the wire insulation in the stator or alternator coil has gotten a bit weak and is leaking some current.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline eurban

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Re: Electrical Odyssy: Complete!
« Reply #6 on: August 03, 2008, 06:31:34 am »
Very nice write up. . . .  I do wonder if there was not some significant variation between stock charging components as they came off of the assembly line. I seem to have been dealt a better hand . . . I have a 78k with a halogen headlight, Dyna III ignition, Dyna 3 ohm coils and all other lights LED.  I am using an regulator from Oregon Motorcycle Parts, aftermarket (brand??) rectifier, stock harness in good shape with clean connections (Tarnx works wonders), clean / tweaked stock fuse box, new ignition switch and handlebar controls,  and a relayed power source for the coils.  My setup charges at idle (13.2volts) and goes up to over 14 above 2500 rpms or so.  I take my measurements for charging at the battery terminals.  Where does your led guage tap in?  If its not from a dedicated line attached to the battery then it will likely read a bit low. Cool gauge BTW.

Offline burmashave

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Re: Electrical Odyssy: Complete!
« Reply #7 on: August 03, 2008, 09:05:44 am »
I agree with you on the LED gauge reading low. Originally, I was going to tap it into the battery; however, I needed a power supply that is ignition switched. The LED gauge reads by volts, so it doesn't give precise measurements. If it reads 12, I don't know if it's twelve going on 11 or going on 13.

I'm using a regulator from Oregon Parts as well.

I'm going to check out the actual voltages with a multimeter this week.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

troppo

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Re: Electrical Odyssy: Complete!
« Reply #8 on: August 04, 2008, 12:52:46 am »
Wouldnt a small mechanical voltage meter be a little more accurate?
Like the ones in the dash of cars.

Offline burmashave

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Re: Electrical Odyssy: Complete!
« Reply #9 on: August 04, 2008, 05:48:58 am »
I think you may be right, troppo. My local auto parts store has a smallish one, but it would not have fit. Diameter-wise, I might be able to fit it somehow; however, it is over 1" deep.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

troppo

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Re: Electrical Odyssy: Complete!
« Reply #10 on: August 04, 2008, 05:54:11 am »
night have to see whats out there, i`m a little worried about the charging system, i would hate to be stranded on the side of the road with a dead battery

Offline TomC

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Re: Electrical Odyssy: Complete!
« Reply #11 on: August 04, 2008, 05:59:26 am »
Hi Burmashave
     Perhaps we need to start a Volt meter thread. I will be interested in how well your LED volt meter compares with the multimeter. I have a LED voltmeter that I checked and discovered it was way out. Also I will be interested to hear if you ride through a down pour with your LED volt meter.
     Do you have any idea what the power draw of your LED volt meter is?
     Currently I have a digital voltmeter wired to the battery of my CB400F1. I turn it on and off when I get on and off the bike. But thats to save the battery of the volt meter. I get to see the voltage down to a hundredth of a volt. But not water proof. The volt meter was rained on and it took about three days for it to dry out and work again. I am thinking about mounting my volt meter in a clear plastic food storage box for water proofing.
     I would be interested in hearing other peoples experiences and ideas with mounting a volt meter on there SOHC4
          TomC in Ohio
I agree with you on the LED gauge reading low. Originally, I was going to tap it into the battery; however, I needed a power supply that is ignition switched. The LED gauge reads by volts, so it doesn't give precise measurements. If it reads 12, I don't know if it's twelve going on 11 or going on 13.

I'm using a regulator from Oregon Parts as well.

I'm going to check out the actual voltages with a multimeter this week.
TomC in Ohio
76 CB750 F1 Daily Rider
76 CB550 stalled project
76 CB400F Injured Reserve

troppo

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Re: Electrical Odyssy: Complete!
« Reply #12 on: August 04, 2008, 06:10:52 am »
G`day tom
I guess with the meter burma is using, as its designed for bikes it would be water resistant at least. But i do like your idea of a thread or at least comparison of thoughts and experiences with these things.

Offline burmashave

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Re: Electrical Odyssy: Complete!
« Reply #13 on: August 04, 2008, 06:46:13 am »
Superb idea guys:

Voltmeters for Bikes?
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #14 on: August 04, 2008, 03:10:57 pm »
It's still not there. :-( I did a hundred mile last week, and it stayed above 13V all day. It dropped down after starts, etc., but still picked up. I took it for a similar ride today, and it started dropping below 13V, and finally, it stayed between 12-13V for the rest of the ride.

So, I put the multimeter on it as soon as I got home. The battery had about 12.2V with the bike off. When I started the bike, voltage climbed just a tiny bit (0.15V) between 2000-4500 RPM.

Given the work that I've already done, my guess is that the windings in either the stator or alternator coil have gone bad, but not so bad that they completely fail. It seems that they go bad sometimes after the bike heats up.

The prob is replacing the stator and/or coil or getting them rewound. A new stator would be unbelievably expensive; however, getting them rewound means taking my bike off the street for what's left of the summer. :-(
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline TwoTired

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Re: Electrical Odyssy: Not Complete!
« Reply #15 on: August 04, 2008, 03:21:58 pm »
Can you measure the resistance of the Field Coil both at the regulator terminals (disconnected), and at the coil itself?

Have you checked the connections under the stator cover?

Did I miss where you reported doing this?

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #16 on: August 04, 2008, 03:40:23 pm »
Thanks, TT. I've bench tested both more than once, although the last time would have been last fall. Every time, the resistance on both checks out O.K.

When I rebuilt the wiring harness, I soldered the connections to the coil and stator.

The problem seems to be intermittent, and possibly related to heating. At this point, about the only thing I haven't replaced are the stator and coil.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline TwoTired

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Re: Electrical Odyssy: Not Complete!
« Reply #17 on: August 04, 2008, 04:58:19 pm »
You should be able to easily measure the field coil from the connections to your R/R (assuming you can still disconnect that).

Still possible to have intermittent wire connections, don't you think?  Could be heat, could be vibration?

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #18 on: August 04, 2008, 07:05:28 pm »
I hadn't given much thought to a vibration issue. Interestingly, when I started it from a cold start this evening, it charged fine.

You're right in that it may still be a wire issue. I did have a charging prob before I rebuilt the harness, but a bad connection, etc. would explain things.

That's a good idea to test at the components (I didn't solder those). I don't mind cutting, though. I think I'll just cut all of the wires to the alt/oil pressure switch and insert a molex connector like they are on stockers. Then, I'll test the stator and coil, pack my multimeter, go for a ride and stop to test as conditions change. That seems to me to be the best plan.

By the way, I know it was aggressive to solder everything except connections to the components; however, I left myself extra cable/wire most places, and I don't mind cutting and resoldering.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline Hush

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Re: Electrical Odyssy: Not Complete!
« Reply #19 on: August 04, 2008, 07:17:50 pm »
Very very cool looking speedo and yacho's Burma, and overall look is a very decent old school CB750.
Nice that you have that look and still managed to fit all the upgrades, now that's class. ;)
I think the thing I most like about motorcycling is the speed at which my brain must process information at to avoid the numb skulls who are eating pies, playing the ukulele, applying make-up etc in the comfort of their airconditioned armchairs as they make random attempts to kill me!!!!!!!

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #20 on: August 05, 2008, 04:20:20 am »
The clock faces came from Carpy. They may be a bit over the top for a non-cafe, but I really like them.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #21 on: August 05, 2008, 04:01:09 pm »
I took a ride today. At the beginning of the ride, the charging system seemed to be working O.K. After riding about 40 miles, it didn't seem to be working much at all. My guess at this point is that it is heat related.

I've gotten some preliminary numbers:

Continuity Testing on Cold Start: Charging System Working
Test    Ohms
Yellow Stator Wires to Each other    0.5 (all)
Yellow Stator Wires to ground    ∞ (all)
White@Regulator to Gnd.    7.8
Black@Regulator to Gnd.    0.5
Black@Regulator to Ign. Main    0.2

Continuity Testing after Failure (after riding 40 miles)
Test    Ohms
Yellow Stator Wires to Each other    0.7-0.8 (all)
Yellow Stator Wires to ground    ∞ (all)
White@Regulator to Gnd.    10.0
Black@Regulator to Gnd.    0.5
Black@Regulator to Ign. Main    0.2

I forgot to collect charging voltage at the cold start; however, here's the voltage numbers that go with the numbers immediately above (after riding/failure):

Voltage @ RPM after Failure
RPM    Voltage
0    12.44
2.0    12.16
3.0    12.26
3.5    12.29
4.0    12.31

I'll edit and post charging numbers from a cold start as soon as I can. By the way, I took TT's advice and measured continuity from the components themselves.
« Last Edit: August 05, 2008, 04:03:28 pm by burmashave »
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline TwoTired

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Re: Electrical Odyssy: Not Complete!
« Reply #22 on: August 05, 2008, 08:20:08 pm »
The white wires feed the Field coil.  This coil makes a magnetic field whose strength determines the max output of the alternator at any given RPM.

The field coil is supposed to be 6.8 ohm.   And a larger resistance will reduce the current flow and the magnetic field strength developed in the alternator.

I recommend you 1,  find out why your field coil resistance is an ohm higher than it should be when starting out.  And 2, why it climbs to 10 ohms after steady use.  I have little doubt this why your alternator weakens with use.

I hate to harp on this, but I would most certainly triple check the wires and connections, even if soldered, between the field coil and the Vreg.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline burmashave

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Re: Electrical Odyssy: Not Complete!
« Reply #23 on: August 06, 2008, 02:07:37 am »
I recommend you 1,  find out why your field coil resistance is an ohm higher than it should be when starting out.  And 2, why it climbs to 10 ohms after steady use.  I have little doubt this why your alternator weakens with use.

Wildo. I also want to double check, just to make sure, that my readings on the field coil are correct. I didn't realize that 10 ohms would be that far out of spec.

I hate to harp on this, but I would most certainly triple check the wires and connections, even if soldered, between the field coil and the Vreg.

You are right. I trust my connections, but I know one of them could  be bad. Also, I joined the new wire with the coil, stator, etc., where the bullet connectors were behind the gearshift cover. The short length of wire from there to the coil could be bad. I'll pull the alternator cover to test at the coil itself in addition to testing the wire back to the vreg. I'll test the other wires as well.
Quote from: SOHC Digger, RIP
'Ere's whatcha do, Guvna', just throw a couple dookie logs in the hearth and bob's your uncle!
'77 CB750k

Offline eurban

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Re: Electrical Odyssy: Not Complete!
« Reply #24 on: August 06, 2008, 04:31:53 am »
The sub wiring harness that connects to the stator etc resides in a nasty environment under those covers.  I have found a number of them in very bad shape.  If you kept any portion of the stock harness be suspect and heck, your new parts and connections might not be up to the heat / oil etc.  Pinching wires upon assembly is a potential issue and make sure that the grommet that seals the wire's exit out the case is in good shape, keeping the wires out of contact with metal.