Author Topic: need wiring harness help '78 K  (Read 11218 times)

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Offline medic09

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Re: need wiring harness help '78 K
« Reply #25 on: December 26, 2006, 01:17:11 PM »
That's one of the coolest things I've seen!  Great learning tool.  Now back to equipment checks for work.  :(
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline medic09

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Re: need wiring harness help '78 K
« Reply #26 on: December 27, 2006, 12:10:26 PM »
Okay, here we go with installment 1 of Adventures in Motorcycle Electrics or Novice in Wonderland (Nightmareland?).


Headlight straightened out, Hi-Lo now working.  Taillight not yet.  Went to the back, and found no power coming to test light through the brown wire to taillight.  Started to look back.  Started to find unpleasant surprises.

Ground loose, no big deal.

PO plunked in a new battery on top of a battery box full of corrosion.  Sooooo, took out the battery box, cleaned up the corrosion (including what had dripped below) with Deep Creep, Simple Green, steel wool, and finally some baking soda with a little water to neutralize any acid that might remain.  When dry, I'll spray it with a coat of black Rustoleum.

Meanwhile I started cleaning contacts.

All the wires to the Rectifier are FRIED, with poor repairs.  In fact, while just picking one up, it broke.  Glad *that* didn't happen during my commutes.

So, do I try and do a proper repair on those wires, or what?
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline 750goes

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Re: need wiring harness help '78 K
« Reply #27 on: December 27, 2006, 12:20:56 PM »
simple answer is yes.....do the repair...just make sure you have enough length of wire to make a good connection before cutting off the bad bits....and do one at a time that way you should not have to reinvent the harness when you are finished..

Tip - go to your local breaker/wrecker and get any old harness from any old bike and cannibalize it for lengths of similar coloured wires for you to use

how are you doing your connections - crimping or soldering ? both? 

Offline medic09

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Re: need wiring harness help '78 K
« Reply #28 on: December 27, 2006, 12:39:40 PM »
I'm crimping.  I splurged and bought a ratcheting crimper.  I've used it so far to repair some sloppy splices up front, and it's much better than the regular stripper/crimper I have.  I figure for the Rectifier wires on using butt splices, crimped and then heat shrunk with the wife's hair dryer.  I guess I can canabalize that F harness that I'm not using now.  Shame to ruin a good harness.  Only other choice is just use plain 18 ga wire that I have, and note in a book what I did.

I noticed with a quick perusal on Ebay that these units used to come with the wiring running into a multi-connector.  I wonder what happened here...

This is quite an education I'm getting here.  ::)

Keep the help coming, guys (and gals) !  :)
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline medic09

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Re: need wiring harness help '78 K
« Reply #29 on: December 27, 2006, 12:43:15 PM »
On second thought, should I do those repairs with connectors instead of splices?  That way I could replace a part more easily if ever needed.  Could heat shrink a sleeve over each connector to protect it...  ? ? ?
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline SD750F

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Re: need wiring harness help '78 K
« Reply #30 on: December 27, 2006, 02:26:05 PM »
Medic09,

Sounds like your last comment is perfect! Good technique and wanting to heat shrink will be the best on top of new crimped connectors on the rectifier. Check and make sure that any heat shrink will not interfere with a connector housing or shroud before you apply heat shrink on those connectors. You might cause a problem where either the connector will not insert properly inside the housing, or prevent the connector from locking in.

The rectifier is a fairly basic device that takes the three phase output of your coil and makes is "noisy" direct current (DC). Then a new RED wire should route from the rectifier to your 15A fuse in the fuse block and the battery positive terminal. Make sure all is good and clean and we can go from there. Once this is done you should have a good charging current to keep your battery alive...

Scott
« Last Edit: December 27, 2006, 02:29:57 PM by SD750F »

Offline medic09

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Re: need wiring harness help '78 K
« Reply #31 on: December 27, 2006, 02:56:44 PM »
Thanks Scott.  I'll follow up on what you said here.

Meanwhile, battery box is cleaned, painted (such as it is, rattle-can Rustoleum with a light coat of plain black over it), and back in.  Components that were bolted to it are back on, after cleaning contacts.  The Rectifier wires will be next.  They're pretty fried, so I hope I don't have to go far back to find good wire to work with.  What would have done that?  Is it likely connected (no pun intended) to the large amount of battery corrosion I found in the battery box?

While I was doing this, I found a green wire unattached to anything.  It was like that when I went to remove stuff.  Now that all the 'local' wires are accounted for, it doesn't seem to have anyplace to go.   ???  Green is ground as far as I understand.  This has a connector like it belonged someplace. 

You'll also notice in the pic that PO replaced the blinker relay with a different one.

Keep the help coming all!  Slowly, I'm going to have this bike in better shape than when I bought it.
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline SD750F

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Re: need wiring harness help '78 K
« Reply #32 on: December 27, 2006, 03:06:09 PM »
Medic09,

Yes you are correct, the green wire you have is a ground. So to answer your question it is best to trace the wire back to the harness end or some where else. Are you going to replace the Rectifier wires? If you are, get a good stranded copper wire 16 gauge with a good insulator. A PVC insulator is the most common but has the lowest temperature rating. But if the wire is properly gauged for the current handling, then the heat it will be exposed to will come from the engine or a home location in the desert... :)

I have attached a good document to verify and select the best wire gauge for current load below.

Scott

Offline SD750F

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Re: need wiring harness help '78 K
« Reply #33 on: December 27, 2006, 03:11:08 PM »
Medic09,

I have another question... Do you have a multimeter or at lease a circuit tester like below? If so great! Otherwise I would suggest a trip to your local automotive supply store and get one. It is also a great tool to have in your bike's tool pouch...

Scott

Offline medic09

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Re: need wiring harness help '78 K
« Reply #34 on: December 27, 2006, 03:36:39 PM »
Medic09,

I have another question... Do you have a multimeter or at lease a circuit tester like below? If so great! Otherwise I would suggest a trip to your local automotive supply store and get one. It is also a great tool to have in your bike's tool pouch...

Scott

I've got a little circuit tester.  Didn't invest in a multimeter, because I wouldn't know what to do with it.  That of, course, is true about this whole endeavour!  :D

BTW, the little green ground wire comes out of the harness at the same place that the wires to the tail, the voltage regulator (it's not from the VR), and the turn signals do.  That's all I seem to be able to figure out.

I'm going to run out to Pep Boys and get some 16ga wire and connectors.  It looks to me though (didn't measure) like the wires coming out of the Regulator are 18ga?
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline 750goes

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Re: need wiring harness help '78 K
« Reply #35 on: December 27, 2006, 03:39:17 PM »
how the wires got fried opens up a new topic

how do you stuff a harness  --  hook up the battery the wrong way around

how do you stuff a harness twice  --  put a battery charger or jump starter on the wrong way

how do you stuff a harness again -- have a friend help you who knows less than you...

all things to be wary of...

my harness was burnt through the earth wire from the rectifier back two feet into the harness - I kept chasing it and eventually undid/unwrapped all the old harness and checked every wire - some hidden surprises were good to find... also coming from the alternator/stator to the rectifier I had some major meltdowns of the plug connectors, plus very loose and corroded connectors..
once you have done a few minor surgeries I'm sure you will trust your electrics a lot more.. :D keep at it

Offline medic09

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Re: need wiring harness help '78 K
« Reply #36 on: December 27, 2006, 03:46:37 PM »
The good thing is, I was commuting 600+ miles/week on the is bike until the cold set in.  I'm inclined to think that the damage is relatively limited.

We shall see...  ;)

Keep the help coming guys.
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline seaweb11

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Re: need wiring harness help '78 K
« Reply #37 on: December 27, 2006, 03:53:37 PM »
I would just mark the extra green as "extra"  and carry on.  Don't stop the progress over the little irritating things.
Sounds like your doing fine.  30+ years with previous owners is more than likely the cause of burnt wires. Trace and find the short, correct them and carry on.

Offline medic09

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Re: need wiring harness help '78 K
« Reply #38 on: December 27, 2006, 04:56:42 PM »
I would just mark the extra green as "extra"  and carry on.  Don't stop the progress over the little irritating things.
Sounds like your doing fine.  30+ years with previous owners is more than likely the cause of burnt wires. Trace and find the short, correct them and carry on.

That's pretty much what I'm doing.  I'll replace the wiring to the Rectifier, then get back to installing the new headlight bucket and getting wires hooked up properly.  Like Scott suggested, I'll go circuit by circuit, with y'all's help.
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline medic09

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Re: need wiring harness help '78 K
« Reply #39 on: December 27, 2006, 07:51:09 PM »
Okay, so after bringing the blood sugar back to normal range with a plate of fettucini and a bottle of New Belgium 2 Below Ale, it was time to do something with those Rectifier wires.  Brace yourselves, this won't be pretty.

The wires from the harness to the Rectifier were all fried; to varying degress, but crispy fried.  The plan was to insert connectors to make replacement or repair easier in the future if need be.  Once the burnt sections were cut out, I had to splice in short lengths of wire to allow the connector halves to approximate.  That still seemed better than just hard splicing everything.  So I've got butt splices from remnants of original wire to bits of new wire to connectors.  Like I said, not pretty.  For now it seems safe and sturdy.  I put the battery back in, and I seem to have power.  When I'm satisfied that I can leave it like this, I'll take same shrink tubing and put it around the connectors, then shrink it over at the ends to protect them, leaving the middle section over the connectors flexible. (Will that work?)  It will still be easy enough to remove if I need to access the connectors.

Pink are the butt splices.  Blue are the connectors.  Green wire is the replacement sections.

Back to tracing circuits tomorrow.
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline 750goes

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Re: need wiring harness help '78 K
« Reply #40 on: December 27, 2006, 09:14:01 PM »
good job....at least you know you have good connections - just as a matter of interest do any of the wires feel hot after the bike is running for a few minutes (not radiated heat from the motor)...

Offline medic09

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Re: need wiring harness help '78 K
« Reply #41 on: December 27, 2006, 09:30:58 PM »
good job....at least you know you have good connections - just as a matter of interest do any of the wires feel hot after the bike is running for a few minutes (not radiated heat from the motor)...

Good question.  Haven't let run that long.  Took the tank back off.  We'll have to find out later.

Thanks for the help and encouragement, all of you!

Back at it tomorrow.  S'pposed to snow, so might as well spend part of the day in the garage.  ;)
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline jdpas29

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Re: need wiring harness help '78 K
« Reply #42 on: December 28, 2006, 03:57:49 AM »
yes.... check for heat and smoke after riding for a while.  warm is usually ok.  hot is not.

and i believe that green wire you pointed out earlier is indeed an extra ground.  just tuck it in somewhere.  make sure that your fuses are the appropriate amp.  that way if you have a problem, next time maybe it will blow your fuse first instead of frying all your electrics.
cars are gay.

Offline medic09

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Re: need wiring harness help '78 K
« Reply #43 on: December 28, 2006, 11:41:27 AM »
Okay, next installment of Mordechai's Electrical Nightmare...

Started the morning with the headlight hooked up as an easy way of verifying that something works.  I'm doing all this first without the bucket on, so that I have a little more room to figure things out.

I went about slowly hooking up connectors.  I figured since it's color-coded, I should be able to do this with just a little help from the diagram.   ::)  Yeah, well that's the theory...  Actually, I had a lot of the stuff working, though it's kind of painstaking.

Where we are now.  Headlight did work, but doesn't now.  Fuse looks okay to me, so...?  Still no taillight.  Parking light works.

Front turn signal switch bundle has a Blue/White wire, and an Orange/White that don't seem to have anything that plugs into their connectors.  ???

There's a brown wire (female connector) at the Main harness bundle that seems like it should be the taillight wire.  There's no corresponding brown wire to plug into it.

Speedo/Tach wires plugged in, no light.  When the Blue/Brown Signal buzzer wire is plugged in, the instruments flash with the turn signals.  If that wire is unplugged, then simply no light at all at the instruments.  BTW, there is no buzzer on this bike.

Okay, that's as far as I've gotten.  A gentle snow has started.  Got to go do groceries so the wife won't come home to an empty cupboard tomorrow. Have disconnected most stuff for now, to start again systematically and fresh.  I'll get back to this in a bit.

Thanks all!
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline seaweb11

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Re: need wiring harness help '78 K
« Reply #44 on: December 28, 2006, 04:23:40 PM »
Personally I would have done it all with the bucket installed. Even if you mark it all...... it is so tight in there that I'm not sure you could read anything.  Anyways good on ya, it will all work when your done. It always does ;D

Offline SD750F

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Re: need wiring harness help '78 K
« Reply #45 on: December 28, 2006, 04:44:25 PM »
Medic09,

Okay lets start with each of your comments form your last post...

Front turn signal switch bundle has a Blue/White wire, and an Orange/White that don't seem to have anything that plugs into their connectors. 

Okay, the Light Blue/White wire is your front right running light. The connector that comes from your hand switch goes into the harness head and right out again. The two front signal lights should have three wires. A Green for the ground, Light Blue for the signal, and a Light Blue/White for the running light. Now the same goes for the left front signal light except replace the Light Blue with Orange for the color on two of the wires...

There's a brown wire (female connector) at the Main harness bundle that seems like it should be the taillight wire.  There's no corresponding brown wire to plug into it.


No the Brown wire at the harness head is actually a spare "parking" light wire that is common with another Brown wire at the ignition switch and should only see 12V when the switch is set to the "Run" and "Park" positions. This wire also like you indicated provides the 12V supply to the running taillight. Not the brake light (different circuit).

Speedo/Tach wires plugged in, no light.  When the Blue/Brown Signal buzzer wire is plugged in, the instruments flash with the turn signals.  If that wire is unplugged, then simply no light at all at the instruments.  BTW, there is no buzzer on this bike.

The Brown/Blue wire should only be attached to the buzzer/horn. Because this wire it grounded when the buzzer button is depressed. The instrument lights use a Brown/White wire that has a two way connector at the harness head that runs all the way back to the 7A taillight fuse that is supplied by a Brown/Blue wire at the harness head that is, now get this, attached to a Black 2-3 way connector which is a ignition switched 12V supply...

I hope this helped... I will try to provide my assistance when I can. I am in the middle of "moving" my business into a new location. Been at my current location for 5 years so I have accumulated quite a lot of junk.... LOL

Scott
« Last Edit: December 28, 2006, 04:46:39 PM by SD750F »

Offline medic09

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Re: need wiring harness help '78 K
« Reply #46 on: December 28, 2006, 04:51:40 PM »
Thanks, Scott!  Seaweb, keep the encourgement coming.

I'll try and apply what Scott pointed out here.  Somehow, I couldn't make sense of it from the diagram alone.  Right now I'm particularly frustrated that I've somehow lost the headlight function.

I'm going to take Scott's earlier approach, and start with just the headlight circuit.  That will encompass headlight, taillight, running lights, and instrument lights.  Blinkers I've got marked and shouldn't be a problem.  Brake light is straightforward.

Okay, now DUMB tool question.  I put my circuit tester to the battery, and it worked fine.  I then tried it on circuits that I know should be receiving power (because I operated them), and it doesn't light.   ???  What's the is novice not doing right?

Thanks all!
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM

Offline seaweb11

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Re: need wiring harness help '78 K
« Reply #47 on: December 28, 2006, 05:08:07 PM »
chase the wire back and make sure there is no break in it. I found plenty when I did mine. But you did say the circuit is working?
Make sure you use a GOOD ground on your light tester. wiggle, wiggle ;D check on positive bat teminal and then check again.

Offline SD750F

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Re: need wiring harness help '78 K
« Reply #48 on: December 28, 2006, 05:37:29 PM »
Medic09,

And another great place to check for 12 volts is right at the ignition switch. You should have a positive indication on the Red wire going into the switch, and when the key is turned the same on the Black, Brown/White (Tailight 1 circuit), and the Brown (Taillight and spare circuit).

This will provide a check to ensure that one, you have a good 15A fuse and primary feed line as well as second, verify that you have a good ground on your test indicator...

Scott

Offline medic09

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Re: need wiring harness help '78 K
« Reply #49 on: December 28, 2006, 07:28:52 PM »
Thanks guys!

Meanwhile...

Scott, you said that the two front signals have three wires.  At first I was confused.  I know I've got only two.  The I realized...I'm working with the bucket off the bike.  The two grounds are integral to the bucket, and the two coming out of each signal lamp are for signals and running lights! Okay, I'm learning...  :-[

So at that point I thought 'maybe Derek is right.  Maybe I should work with the bucket in place right away.'  That's when I discovered that the stock bucket I bought isn't the same as the one I thought to replace.  The stock bucket is HM-20M.  It's a little wider than the ears I have on the bike (which look nicer than stock, methinks), though I could just gently bend them out to fit it in.  The bucket I took off the bike is HM-43M.  The real difference that interests me is that the 43M seems to have more room for fitting wiring into the bucket, as well as several access holes in the back to fit stuff through. (It also lacks a screw hole for the top anchoring screw of the headlamp, but I can always drill one.)

This leads us to the newest DUMB NOVICE QUESTION:  how much of the wiring is actually supposed to be inside the bucket?  All of it?  Or...?  If some is left out, how do I protect it?

Also, from Scott's last detailed answer (I really appreciate all your effort!), I'm left with two female connectors at the Main harness bundle that I have nothing to do with.  One brown, and one blue/brown.  I also understand that I just leave the blue/brown male from the signal switch bundle hanging, because that would have gone to buzzer?

Okay, I'm now confused and probably will need a step by step 'plug it here' to get me going again.  I was just out in the garage looking at the mess, and I don't seem to have any better idea why the headlight/taillight/instrument lights circuit isn't working.

I await your answers/suggestions.  Scott, good luck with the move!
Mordechai

'78 CB750K
'76 Triumph T160 Trident (rebuilding)
'07 aprilia Caponord

Santa Fe, NM