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Old 10-23-2012, 02:41 PM   #1
thekinghimself OP
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Location: Los Angeles, CA
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Bultaco restoration project – Electrical Gurus… Please look!

OK, I’m confused, lost, discouraged a little bit disappointed in myself…and I need help.

And no, I’m not talking about the actual decision to purchase and restore a 1972 Bultaco Matador mkIV, (although the intelligence of that decision is questionable), but it’s the electrics!!!

Calling all ancient electrical system gurus… I need help!

I know you guys like photos, and in the interest of a good entertainment (and greasing the wheels a little bit) , here are some pics:

In the back of my truck the day I found her. ($200, definitely over spent☺)


A few gruesome teardown pics…..






Where I’m at now: (Almost finished!)





Total tear down, frame powder coated silver, much $$$ on eBay and Hugh’s Bultaco here in the states. Mucho elbow grease and marital strife applied of course.

Hopefully my last frontier is the wiring.

Here are the ONLY wiring diagrams I can find on a electronic (Femsa) ignition model with a battery: (from the Clymer Vintage Dirt Bike Manual)




I have some basic assumptions and questions that If I can get them confirmed and answered, I might be able to walk my way outa this confusion by myeself. ☺

Assumption #1 This bike has a single phase 6 volt permanent magnet generator. (all bulbs are 6 volt)

Assumption #2 The stator has two outputs. One for ignition and one for lighting and charging the battery.

There are literally 6 wires coming from the stator, so it’s a little confusing. 3 go to
the coil (btw, the bike DOES have spark and will run), and 2 to the rectifier and one
to the ignition switch (battery negative) . Two of these wires going to the rectifier
should have 18volts when the bike is running per the Clymer manual. If someone could explain this
arrangement to me, that would be fantastic!

Am I correct in my assumptions?????

Question #1 Is this a Positive ground system?

The wire from the (-) battery terminal goes to only one place, the ignition switch. Following the wiring diagram, the headlight and horn switches seem to be switching the rectifiers NEGATVE output to the horn, headlight, tail and stop lights.

Question #2 If this IS a positive ground system, why is there no connection from the battery positive terminal and the frame? Is the diagram simply missing the (+) positive ground strap? The headlight (for example) receives rectifier (-) from the headlight switch and the single output of the headlight goes to a ground lug in the headlight bucket. But with to ground strap, how does it get back to (+) on the battery?

It seems that battery equipped Bultacos were quite rare. I belong to several Bultaco and Trials forums, and I I’m yet to get the info I need. Matadors just a year earlier than this model were points equipped and the lighting was part of the ignition circuit with flaky resistors in the tailights. There’s plenty of info on this system, but almost none on mine.

I have a good chance of getting this thing street registered here in CA if I get this sorted out. (with mirrors and ornamental turn signals of course)

I bow to the awesomeness of the collective genius and experience here at ADVRider, and I await enlightenment. ☺

Thanks in advance guys! - Jeff
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Old 10-23-2012, 10:31 PM   #2
redprimo
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I'm not an electrical guru and I don't play one on TV but I'll take a stab at some of your questions.

First is that it is a negative ground system. the negative side of the battery goes to the ignition switch and then it is grounded to the frame.

All generators create AC electricity. on your lighting circut the AC current is converted to DC current by the rectifier and then is dumped into the battery. There are some systems where the rectifier is also a regulator. Youll have to wait for a real guru to clarify that for you.

If it were me I would get some colored marking pens and color the schematic acording the the key so it is easier to refer to when working on the bike.

A deoxit kit from an electronics store will really work wonders on cleaning the connectors and go a long way in brightening up your lights.
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Old 10-24-2012, 12:45 AM   #3
Beezer
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I bought one new in 72.... the ISDT replica one which I really wish I could have back (long gone... sold in the late 70s). they did not have turn signals when new.

a few years ago I sold a spare left side engine cover (the part with the flange for the chain rubber) for $220 plus shipping to a guy in Spain.

too tired to think about it now but I'll check back
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Old 10-24-2012, 08:11 AM   #4
thekinghimself OP
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Thank you Redprimo. Maybe this is part of what I'm missing.

So let's talk about the ignition switch.


What's the decision process here? My take was:
Ignition on : Battery (-) to wiring loom (the dotted line)
Ignition off: Battery (-) to frame ground

Am I wrong?

Is it:
Ignition on: Battery (-) to both frame ground and the wiring loom (dotted line)?

So, kinda a switch ground strap?

I will try and make a colored schematic today. I would be easier. - Jeff







[QUOTE=redprimo;19886859]I'm not an electrical guru and I don't play one on TV but I'll take a stab at some of your questions.

First is that it is a negative ground system. the negative side of the battery goes to the ignition switch and then it is grounded to the frame.

thekinghimself screwed with this post 10-26-2012 at 06:14 PM Reason: additional info
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Old 10-24-2012, 11:20 AM   #5
NJ-Brett
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It looks to me like they open up the ground to shut things off.
It is a neg ground setup.
With the key on, the battery gets connected to ground so things work, but they are also switching another wire (E) going to the rectifer and stator.
Rectifiers have 4 wires two ac in from the stator, and a + and - output.
The key connects the - to ground.

The generator thing is a cdi setup. It gets power and a trigger from the stator.
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Old 10-24-2012, 02:34 PM   #6
thekinghimself OP
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I my online research I found a article online regarding british wiring: (from: http://www.angelfire.com/biz/snwvlly/bikes/poswire.htm

Quote:
"Most British Motorcycles are Positive Ground, or "earth" - meaning simply that the return path for current from the various devices to the battery is accomplished by using the chassis as a conductor. The battery (+) terminal - red wire - is "grounded," or "earthed" - connected directly to the chassis. The battery (-) terminal is the "hot" one (relative to the chassis) and is the one run through switches and conductors and run to the various devices - ignition, lights, horn, etc."

I know the Bultaco isnt British. But I'm grasping at staws here.

My diagram fits the bill for POSITIVE ground as the (-) terminal is being switch and routed, AND I do have hot being terminted to ground in the headlight shell.

Well, snap, I also have (-) terminated in the headlight shell through the current stabilizer!


In this diagram RED is (+) and Blue is (-) - both feed from the rectifier.

As requested and advised, color wiring diagrams:




and the all important KEY for the connector in the middle. The Rosetta Stone if you will :)


Thanks again everyone for looking at my post.

All input and help is VERY much appreciated. - Jeff


Quote:
Originally Posted by NJ-Brett View Post
It looks to me like they open up the ground to shut things off.
It is a neg ground setup.
With the key on, the battery gets connected to ground so things work, but they are also switching another wire (E) going to the rectifer and stator.
Rectifiers have 4 wires two ac in from the stator, and a + and - output.
The key connects the - to ground.

The generator thing is a cdi setup. It gets power and a trigger from the stator.

thekinghimself screwed with this post 10-26-2012 at 06:24 PM
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Old 10-24-2012, 03:24 PM   #7
mike in idaho
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Putting a master switch between the negative battery cable and ground is commonly used in Caterpillar and other brands of heavy equipment. Works really well that way, simplified wiring, one high amp switch in the ground cable makes everything electrically dead when it's off.
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Old 10-24-2012, 11:41 PM   #8
redprimo
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I'll type slower this time so you can understand . It is a negative ground system. The negative side of the battery goes to the switch and then to the frame.

having the switch control the negative ground is actually the correct way to wire a 6v circut but it is not the common way it is usually done.
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Old 10-25-2012, 07:19 AM   #9
thekinghimself OP
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Alright, alright.

I thank you for your persistence. I wish I had the original ignition switch to test (and then there would have been no question), but my bike came with a raped electrical system with a toggle wired in instead. I suppose having a switched frame ground would completely protect the battery from draining.

The reason that I am hesitant is that I see inconsistencies in the wiring diagram I have.

For example, the ONLY 2 places battery (+) goes to is the horn and the taillight. For the horn to work, it needs a switched (-) to complete the circuit, correct? (It's waiting for (-))

Take a look at the headlight and horn wiring:



The blue wire in the input to the horn/headlight selector switch.
If the horn switch is supplying (-) negative to complet the horn circuit, it is ALSO supplying (-) to the headlight.

Look at the red wire out of the headlight. Terminates to ground in the headlight shell. That suggests POSITIVE ground.

I'm going to ruminate on the wiring diagram for a bit and see if it all makes sense before my next re-wire attempt or posting.

Thanks again everyone for you input. - Jeff





Quote:
Originally Posted by redprimo View Post
I'll type slower this time so you can understand . It is a negative ground system. The negative side of the battery goes to the switch and then to the frame.

having the switch control the negative ground is actually the correct way to wire a 6v circut but it is not the common way it is usually done.

thekinghimself screwed with this post 10-25-2012 at 08:48 AM
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Old 10-25-2012, 09:33 AM   #10
mike in idaho
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Looks like the ignition switch breaks the battery ground connection and also grounds the ignition, to shut things off.
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Old 10-25-2012, 06:21 PM   #11
redprimo
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I think the problem your are having is that you are getting hung up/confused by the wire colors. The red wire comming out of the headlight and connected to the head light shell is picking up the negative from the battery. Remember that the neagative side of the battery is connected the the frame when the ignition switch is turned on. That red wire then takes the negative to the headlight and the bue wires deliver the posative ( one is your high beam and the other is the low beam. You could do exactly the same thing by routing the negative directly to the lights with wires rather then the frame but that would take more wire and more labor.

Your horn circut is a bit odd. It is has the posative going directlhy to it from the battery and the neagative is going up to the switch and then back to the horn. most horns pick up their negative directly from the frame abdd te posaive is switched i.e. when it is connected by the button the horn makes noise. What makes your horn circut so odd is that the dimmer/horn switch has posative from the light circut and negative from the horn and most switches only have posative or negative but not both.

It would be a bit clearer if all the ground wires were green or green with a colored stripe to indicate what circut they were providing ground to. Green or black is the traditional color used to indicate ground with green being the prefered color.
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Old 10-26-2012, 07:41 AM   #12
thekinghimself OP
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Redprimo, you are blowing my mind!

I don't think the colors of the wires are bugging me, but MAN, that is weird signal flow.

I'm done trying to understand, I'm gonna just do.

At this point, I'm planning to rewire the bike with a more straightforward neg ground system. It's just a headlight and taillight for god's sake. I plan to throw in an aftermarket Reg/Rec to replace the burnt rectifier and loose the "Current stabilizer".

In my research, I found this website of a small business in Oregon that offers rectifiers and regulators for old bikes:
http://www.oregonmotorcycleparts.com/index.html
It's run by a nice guy named Tony, and he's been trying to help me with a replacement regulator choice.

I'll re-post when I'm done, or if there's any interesting developments or plot twists.

Thanks everyone. - Jeff


Quote:
Originally Posted by redprimo View Post
I think the problem your are having is that you are getting hung up/confused by the wire colors. The red wire comming out of the headlight and connected to the head light shell is picking up the negative from the battery. Remember that the neagative side of the battery is connected the the frame when the ignition switch is turned on. That red wire then takes the negative to the headlight and the bue wires deliver the posative ( one is your high beam and the other is the low beam. You could do exactly the same thing by routing the negative directly to the lights with wires rather then the frame but that would take more wire and more labor.

Your horn circut is a bit odd. It is has the posative going directlhy to it from the battery and the neagative is going up to the switch and then back to the horn. most horns pick up their negative directly from the frame abdd te posaive is switched i.e. when it is connected by the button the horn makes noise. What makes your horn circut so odd is that the dimmer/horn switch has posative from the light circut and negative from the horn and most switches only have posative or negative but not both.

It would be a bit clearer if all the ground wires were green or green with a colored stripe to indicate what circut they were providing ground to. Green or black is the traditional color used to indicate ground with green being the prefered color.
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Old 10-26-2012, 09:50 AM   #13
Rob Farmer
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Electrex in the UK make nice quality electrical parts for older machines. They make a new unit including the lighting circuit for Bultacos. Not cheap but may be worth contacting them to see if they can help you http://www.electrexworld.co.uk/cgi-b...rch&PR=-1&TB=A

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