Topic: voltage regulator testing, and wiring fun

[McGriff]

1974 CB750



my voltage regulator shows no resistance between green, yellow and black wires, any combo.  that seems wrong to me, but i am semi wiring inept

Black power wire was showing no resistance to ground until i unplugged the voltage regulator
If it is bad, any suggestions for a new one? Is a combo regulator rectifier a good idea?
Can i get lights (all of them) working without having it connected or am i missing some connection on the wiring diagram

on another note, i blow the main fuse every time i turn the headlight on, metal headlight ears and headlight bucket, connected to the blinkers (i am in the process of running down each wire 1 by 1 so I'll get it eventually) but the headlight needs to not be grounded to the frame, and the blinkers also need not to be in any way connected to the headlight  (besides ground)  i think i have them all isolated, but its on the list of things to check.

rewiring due to accident, broken headlight basket and turn signals, new spedo/tach and relocated ignition with nuetral+ oil pressure light attached, just trying to get things to light up for me without the little flash associated with blown fuses (speaking of fuses i rewired in the spade style ones to eliminate that from the possibility list)

New coils from Parts-n-more, anything i should look out for with those?  i already insulated the original mounting brackets with plasti-dip to prevent shorts to ground there, and shouldn't enter the equation until i actually start the bike right?  right now i just want to get the basic stuff working, then I'll move onto the charging/ignition side of it.

Sorry to post such a long one, but this stuff is frustrating and it helps to walk away for a minute before i start ripping wires out.  Maybe more beer would help 
Ahh the joys of wiring, time to clean and trace connectors and wires

[scottly]

1974 CB750



my voltage regulator shows no resistance between green, yellow and black wires, any combo.  that seems wrong to me, but i am semi wiring inept

Black power wire was showing no resistance to ground until i unplugged the voltage regulator
If it is bad, any suggestions for a new one?

The green wire IS ground, the black wire is connected to the white wire through the reg, which is connected to ground through the field coil (actually should be about 7 ohms resistance).

[Duke McDukiedook]

I would recommend hooking it up and seeing what voltage goes across the battery terminals before you go buying a new R/R.

I had a completely bad coil I bought from partsnmore, chalk it up to Taiwanese junk I guess.

[scottly]

I would recommend hooking it up and seeing what voltage goes across the battery terminals before you go buying a new R/R.

1+ Also, the reg probably has nothing to do with your other problems.

[McGriff]

The green wire IS ground, the black wire is connected to the white wire through the reg, which is connected to ground through the field coil (actually should be about 7 ohms resistance).

Soo  does that mean with the regulator hooked up i should show about 7 ohms resistance from ther black wire to the ground (green) wire?  I get no resistance when regulator is attached, and infinite when not.    i have been trying to find the short from the black wire (which i thought was the + / power) i have been testing black and green at the rats nest that used to be the headlight bucket mess.

I don't doubt that the regulator is fine, opened it up and nothing looked toasted (very sientific i know), guess i need a tutorial on basic electronic principles.

I would love to try it out in running conditions to make sure it's ok (seen the methods on several posts, TT's being one of the better ones) but no tank or exhaust on it now.  Trying to get the wiring figured out while i wait for it to get warm enought to paint the tank

How about if i just disconnect evreything (again) and start fresh, is there a good order to connect in that would make it easier for me to trace any bad connections or should i just try doing one item at a time until i find the wire that causes fuse blowage

[McGriff]

also Where does the ground  (green) wire attach to the frame?  is it only the Neg battery cable attached to the engine mount bolt, or is the ground wire attached at a different point as well?  taking the advice of the forum to heart i feel as if i should go through a check for bad grounds and 36 year old wires that may have never been cleaned

[scottly]

If the fuse only blows when you turn the headlight on, it doesn't have anything to do with the black wire. Someone on here has suggested hooking up a light bulb in place of the fuse to help trouble-shooting shorts without wasting a bunch of money on fuses. Whatever you do, don't start hacking and cutting wires!  

[scottly]

also Where does the ground  (green) wire attach to the frame?

The green wire from the harness is grounded under one of the coil mounting bolts. BTW, a bad ground won't blow fuses, but cause all sorts of grief.

[scottly]

Dude, you insulated the coil brackets, with plasti-dip, where the green wire from the harness is grounded!!!???

[McGriff]

Well then that messes with my theory, but thinking about it i guess grounding out wouldn't blow the fuse, only running too much power thru it, not running to much power thru the frame.  So know i look for the mis-routed wire again.  maybe i should re-color all the aftermarket wires to the honda colors with tape so i know where things are going wrong.  That and a pad of paper, the multi-meter, wiring diagram, 6 pack and a spare few hours and i'll be all set (finger crossed)



i don't seem to have any resistance from the ground to the frame, so i will assume for now i remembered to reconnect the ground at the coils, i'll double check when i get out of work cause assuming i knew what i was doing is what got me into this predicament in the first place.

Hey, give me a break i said i was a little daft on the wiring thing, i just painted the plasti-dip on the up side where the "in" wires attach so it wouldn't ground out, tip from another post where someone had the same issue.  I have to check to make sure i reattached that wire.  do the coils themselves need to be insulated from ground at the mounting point?  doesn't seem that way if the ground wire is attached there.  i'll go back and look at the original ones and try to copy the set up from people who actually knew what they were doing

[scottly]

No, the coils are insulated inside. They don't need to be grounded, but they don't need to be insulated, either. Honda felt that metal to metal point was a good place to tie the green ground wire to the frame. (where is Lyons, by the way?)

[McGriff]

Cool thanks, one thing i can check of the list. 

Lyons in a little north of Boulder, CO on the way to Estes Park and Rocky Mountain National Forest.  I actually live in Boulder now, guess i should update my profile.

Any tips on something i could do to stop wasting the fuses by blowing them when i try and see if my latest wiring is correct?  I apriciate the job of the fuse and the fact that it is making it so i don't melt all my wires, but after 8 of them now i feel like i am just wasting money every time i turn the ignition.  MM attached at the fuse point?  test light? more patience and less "lets see what that did" then turn on and POP.  i don't want to fry anything so if my options are fry wires or fuses i'll go fuses every time.

[scottly]

If the fuse only blows when you turn the headlight on, it doesn't have anything to do with the black wire. Someone on here has suggested hooking up a light bulb in place of the fuse to help trouble-shooting shorts without wasting a bunch of money on fuses. Whatever you do, don't start hacking and cutting wires! 

[McGriff]

Ha  guess i should pay a little more attention.

Thanks Scotty, you've been a big help, i'll post back when i get it figured out, or zap myself.  i'll try to keep the beer bottles off the top of the bike too, seems like it could be bad to spill beer on the wires 

[scottly]

Don't commit alcohol abuse, especially on the spark plug wires, or you will find out what kilo volts feel like!!!
Please let us know what you find...

Scott

[McGriff]

just a thought but if i am blowing fuses wouldn't i burn out the light bulb too?  i guess i would just need the right light bulb with enough to not blow out with over 15amps coming into it.  must read up on that other post.

[scottly]

The light will limit the current to a safe level, the brighter it glows, the more current is flowing.

[TIM TINGEY, age 55]

I'm not sure why your trying to measure resistance values at your voltage regulator since there are none listed or shown in a factory s/m. The values shown are for the field coil. Since you've relocated your ign/switch make sure the black wire coming out of it isn't shorted. This wire is a general power wire that goes directly back to the voltage regulator to provide it the current needed to adjust battery charging current and overall system voltage. If it's shortred it will certainly blow the main fuse when the key is turned to on. Also with the key off, check continuity from the black wire to ground-there should be none. Note that the coils must be grouned where they bolt to the frame because there is a green wire coming off the wireharness that grounds at the mounting points. You can contact me at timmanyatingey@yahoo.com.

[scottly]

Also with the key off, check continuity from the black wire to ground-there should be none.

That black wire also goes to the coils: if either set of points is closed, there WILL be continuity to ground....

[TwoTired]

1974 CB750
my voltage regulator shows no resistance between green, yellow and black wires, any combo.  that seems wrong to me, but i am semi wiring inept

Considering the stock bike Vreg has Black, WHITE, and green wires attached, I've not much clue as to what you are actually attempting to measure.  However, with the vreg disconnected from the bike.  The black to white terminals ought to have zero ohms. and either the white or black to green terminal ought to have about 36 ish ohms.

Black power wire was showing no resistance to ground until i unplugged the voltage regulator
If it is bad, any suggestions for a new one? Is a combo regulator rectifier a good idea?

One method of electrical system repair is to keep replacing components until it works as expected.  This method is most acceptable when someone else is paying for the replacement parts.
Personally, I like to troubleshoot to a faulty component and just replace the bad one.
Can't say I favor random measurements, though.  The black wire in the wire harness is +12V battery power switched through the key switch.  If you get zero ohms on that wire measured to the green wire or frame, you can expect fuses to display a very brief imitation of a lamp.

Can i get lights (all of them) working without having it connected or am i missing some connection on the wiring diagram

Um, you want the lights to work without the vreg connected to the bike?  Sure, that should work.  I don't know why you wish to do that, though.

on another note, i blow the main fuse every time i turn the headlight on, metal headlight ears and headlight bucket, connected to the blinkers (i am in the process of running down each wire 1 by 1 so I'll get it eventually) but the headlight needs to not be grounded to the frame, and the blinkers also need not to be in any way connected to the headlight  (besides ground)  i think i have them all isolated, but its on the list of things to check.

Huh  What is the fuse rating you are using?
What is the headlight rating you have connected?
If you unplug the headlight from it's socket, do fuses still blow?

rewiring due to accident, broken headlight basket and turn signals, new spedo/tach and relocated ignition with nuetral+ oil pressure light attached, just trying to get things to light up for me without the little flash associated with blown fuses (speaking of fuses i rewired in the spade style ones to eliminate that from the possibility list)

So, i guess things got smashed up front in an accident.  You will have to carefully examine all the wires up there to find damaged insulation, which allows the center conductor to contact metal bits.

Maybe more beer would help 

Beer is not known to encourage higher brain function.  Alcohol has the opposite effect, in most cases. (my experience, anyway. In fact, I've known alcohol when mixed with humans and electricity to result in severe burns, and even death.)

To envision unseen electrical flow, is usually a cerebral affair, and generally requires at least a partially functioning brain.  The more brain cells assigned to the thinking task, usually eases such a task.  You might consider removing alcohol from the electrical diagnosis portion of the day. (in the interest of progress)

Saving the cost of fuses.
A small instrument bulb will illuminate nicely if both its terminals are attached directly to the battery. Notice it doesn't burn out.
Connect the bulb in place of where the fuse connects.  If the circuit has a short to ground, the lamp will glow with the same intensity as it did when connected directly to the battery.  When you remove the short circuit error, the lamp will dim noticeably.  You can use this feature to wiggle, disconnect, etc circuits to isolate where the problem lies.

Cheers,

[McGriff]

check, Vreg off the bike, white & black ->green 36ish ohms.  doesn't sound like it has anything to do with my main fuse blowing anyway.

Yup, I made a very useless short lived lamp

yeah, the whole random test and disconnect "method" isn't working out so well, Don't know why, it sounds so reliable.....

headlight disconnected, fuse still blows (15A main, not the 7.5A headlight) when i turn it on from the RH control, not until then though.   

I must have mis-wired somewhere in the process.  I'll set aside a few hours to sit down in front of her, play some nice music and talk real sweet with a few colors of tape, pad and pen, multimeter and wiring diagram.  thanks for the light bulb idea guys.  I'll skip the six pack for the sake of progress

[scottly]

headlight disconnected, fuse still blows (15A main, not the 7.5A headlight) when i turn it on from the RH control, not until then though.   

That is a MAJOR clue!!!

[faux fiddy]

Didn't read his wholehread,but Here's a  thread  for reading. $13 ford regulator substitution.

http://forums.sohc4.net/index.php?topic=12465.0

[Spanner 1]

Wow, TT is back and has stuck his acerbic wit in the pencil sharpener  and it's come out sharper than ever.......!

[McGriff]

OK went at it with a more systematic approach (not to hard since i was way out of the realm of systematic with my other approaches

Disconnected everything.

No ground attachment at the coils, no wire to attach there. Ran extra green wire i had to frame bolt just to make sure i had a good ground.  I'll run a more official one before final assembly

attached neutral indicator light, ignition on, ohh green light 
attached oil pressure light, ahhh red light 
attached coils, nice still have indicator lights
attached VReg, yup still have lights
Attached black wire from headlight switch into harness
attached headlight blue, yellow, white and green...yay headlight, high beam and all, with indicator light (drag specialties, H4 bulb, built in indicator light for high beam)
attached Left blinker and buzzer (missed the buzzer while disconnecting) beeps and lights
attached Right blinker.. hmmm neutral and oil pressure flash. took the blinker off the bike, reattached wires.. OK blinker only flashes.  Blinker itself is grounded to frame. insulate, reattach, Alright blinkers, and only blinkers flashing
turn on headlight, Marker lights work, blinkers work
attached black from kill switch.  Pop (should have used the lightbulb, would have saved me $.85)
removed RH switch from handlebar, OK no BRIGHT light from test bulb.

so it looks to me like i have the kill switch grounding out to the housing then to the handlebars.  i saved a good post on how to rebuild these switches, looks like that might be the direction i am headed.

during all this i cleaned and checked the wires and connectors for signs of damage and filth, looking much better now.

on another note, any good ideas on what i can use to replace the headlight bucket as a place to store all the wiring?  i was thinking black PVC or a box of some sort i can seal of from the elements and mount behind the headlight or somewhere in that area, but I'm getting ahead of myself again, and we all saw where that got me yesterday.

All in all a productive morning.
Thanks All.

[TwoTired]

Nice to see a methodical approach.  Well done.

Is your kill switch stock or aftermarket?

[McGriff]

stock switch.  i had this problem on the 550 and did a less than correct way to fix it by wrapping the bars where the control clamps onto the bars with electrical tape.   That worked for me, but i know it doesn't fix the actual problem i was having, i expect it to come back and cause problems further down the line.  At least if i actually fix the problem on the 750 i will be well versed in the procedure to fix it on the 550, i don't want to mess with both bikes at once, cause it's warm enough to ride and i like to have a bike that is working to play with.

Thanks for your help, progress makes me feel better about of myself