Topic: Regulator Fali?

[brycegp]

I am running the "REG 1007" RR combo unit on my bike, 1975 CB750F wiring harness.  And my bike is grounding out.  I have 12 volts running thru the frame...and I have run continuity test from the frame on every + lead to find the wire the this is grounding out to the frame.  I haven't found any wire that is causing this.

What I do know regarding the three Regulator wires, green, white and black, when the system is HOT, ignition on the RUN setting.
The black wire from the Alternator has continuity to the frame.
The white wire from the Alternator has continuity to the frame.
The green wire ground to the alternator also has continuity to the frame (obviously).

When I unplug the black wire from of the RR combo unit:
The black + leads throughout the bikes's no longer show that 12 volts running thru the frame.
The white wire from the Alternator has STILL continuity to the frame.
The green wire ground to the alternator STILL has continuity to the frame (obviously).

Can this mean that the regulator has failed?  And when it fails can it just cross the POS to the NEG side, inside the regulator?

Thanks!
Bryce

[Spanner 1]

Situation normal, all O.K. ...... The frame on the bike acts as the 'second wire' to make the various circuits work. While Black/Red/Brown make connection to the + battery pole, the frame and motor are connected to the battery - pole to complete the circuit. Really you have just tested the ground paths on some circuits.
If your bike was 'grounding-out' then the main fuse (15A) would blow....
To achieve ' no continuity' from say, the black wire to ground you will have to disconnect the coils, the headlight ( if 'on' ), the tail light, the running lights ( if present ), the N light, the oil pressure light the black wire @ the regulator,........... what I'm saying is that Black will always show continuity to ground unless you disconnect everything connected on that circuit.
You haven't said what's wrong with your bike in your post?.... does it run, not charge or something ?

[brycegp]

First off, I have relocated all the electrical under the tail hump.  I used a CB750F wiring harness.  And here is the problem.

A couple weeks ago, I was riding and the bike died all of a sudden while cruising along at about 60mph.

I inspected.  No blown fuses.  But I found that all the green grounds that I had secured to the frame in one spot on the tail had come loose and no longer where attached to the frame.  The bolt came out.  Fortunately, I had another bolt on me...ahaha...I'm sure we all do, right?

It came right back to life BUT the headlight wasn't on and the neutral light didn't work any more.  But it ran fine...so I tried getting it home.  I was 20 minutes from home.  But after about 15 minutes the bike died in what seemed like the exact same manner.  Back on the side of the road I went.

But this time the ground wires were all still secure.  But now the battery had swollen and was leaking fluid.   And at that time, my issue was mainly that the battery couldn't hold a charge and had to get towed home.

My thoughts were that when the ground wires started coming loose (before the bolt fell off all together), it would have had inconsistent ground...and an inconsistent ground might have put to much strain on the regulator causing it to fail.

That may be a dumb conclusion...but that was my theory.

[Spanner 1]

I think the reg/rect unit when 'ungrounded' allowed a voltage spike that has possibly blown your headlight and N light.... can you connect the h/l to a battery and see if it's good / ( test hi and lo beams ).... also the rectifier portion of the unit may be shorted..... . You could charge your battery and with the R/R unplugged or removed, turn the ign. 'on' and start the bike. If it runs and the h/l, taillight work ( assuming they are still good! ), would  point to the R/R.

[brycegp]

I think the reg/rect unit when 'ungrounded' allowed a voltage spike that has possibly blown your headlight and N light.... can you connect the h/l to a battery and see if it's good / ( test hi and lo beams ).... also the rectifier portion of the unit may be shorted..... . You could charge your battery and with the R/R unplugged or removed, turn the ign. 'on' and start the bike. If it runs and the h/l, taillight work ( assuming they are still good! ), would  point to the R/R.

It runs.  And the headlight, taillight work....no blown fuses.  Charging the battery was never a problem.  Still has 14.5V at 3500 RPM.

What is concerning is that when my meter Black is on the NEG side of battery and meter Red is on Frame...it reads 12V.  The frame is HOT...?  But not popping fuses....

[wrenchmuch]

What is concerning is that when my meter Black is on the NEG side of battery and meter Red is on Frame...it reads 12V.  The frame is HOT...?  But not popping fuses....
[/quote]

This is very puzzling. The frame is connected to battery neg.
Placing a test lead on battery neg and the other lead on the frame is like placing both leads at different points on the same conductor. You shouldnt get any reading. I wouldn't do any further testing with the battery in the bike till you get this sorted.

[Spanner 1]

O.K. then. The only way you could read + voltage to frame ( ground ) as described would be a very poor main ground, i.e. the fat ground wire from the battery - to the frame/motor. I would go straight to that area, undo the ring terminal, shine it up, withdraw the motor mount bolt it is attached under and shine the frame/terminal mating surface. Did you paint your frame maybe.?  Lot's of guys paint their frames and neglect to remove all paint where the ground terminal goes 
A poor main ground could wreak havoc with any electronics on your bike BTW.... in your case, the solid state R/R.

[TwoTired]

Normally, Battery neg terminal attaches solidly between engine case and frame, making both those units common.

Did you do away with this connection?  Where does your battery NEG cable attach?

[lucky]

I am running the "REG 1007" RR combo unit on my bike, 1975 CB750F wiring harness.  And my bike is grounding out.  I have 12 volts running thru the frame...and I have run continuity test from the frame on every + lead to find the wire the this is grounding out to the frame.  I haven't found any wire that is causing this.

What I do know regarding the three Regulator wires, green, white and black, when the system is HOT, ignition on the RUN setting.
The black wire from the Alternator has continuity to the frame.
The white wire from the Alternator has continuity to the frame.
The green wire ground to the alternator also has continuity to the frame (obviously).

When I unplug the black wire from of the RR combo unit:
The black + leads throughout the bikes's no longer show that 12 volts running thru the frame.
The white wire from the Alternator has STILL continuity to the frame.
The green wire ground to the alternator STILL has continuity to the frame (obviously).

Can this mean that the regulator has failed?  And when it fails can it just cross the POS to the NEG side, inside the regulator?

Thanks!
Bryce

The CB750 has only 3 fuses. Use your volt/ohm meter and take one fuse out at a time and see if you still get 12 volts from the frame. I bet it is a light switch causing the short. But it seems like it would blow the fuse if it was.

If you put your meter on battery ground, and the positive lead of the volt ohm meter on the frame,  you mean you get 12 volts???

[brycegp]

If you put your meter on battery ground, and the positive lead of the volt ohm meter on the frame,  you mean you get 12 volts???

yes

[lucky]

With the engine OFF???


Well that is solid information.

Now take one fuse out at a time and see if you get 12 volts on the frame with any of the three fuses out. See what I mean?

[Bodi]

With custom wiring anything is possible.
You should have one good thick wire directly from the battery "-" to a frame bolt (main frame, not a bolted on sub-frame) with bare metal underneath the terminal. This is absolutely a must. If you have electric start this wire has to be 8 gauge at least. For no electric start I would use 12 gauge minimum.
If you lost ground, an electronic regulator and the rectifier could have been destroyed. Electronic ignition too.
Make sure the ground wire is solidly connected, and go from there. If the battery has bulged it is trash. Once all connections are good you can see what other problems you have. The rectifier diodes rarely fail "short" but can, this can melt wires. A failed electronic regulator might do the same. I would disconnect these parts and see if the system works on (a well charged) battery - lights and ignition as normal. After that's all kosher go on to check the charging system.

[brycegp]

Thanks guys!  I've enlisted the help of a professional electrician...we'll get er figured.  ...he's running all Multimeter tests to isolate the issue....then rerouting all wires...redoing any questionable connections...bundling it all for a professionally installed harness.