Ironhead Regulator contacts welding shut

[CaptainZoop]

I recently swapped a 77 ironhead motor from a swing arm frame into a hardtailed frame. I had to relocate the old Bosch style regulator from the rear of the bike to a mount that sits ontop of the 65a generator and also upgrade to a smaller battery (AGM YTZ-12S from lowbrow). The bike fired right up and charged fine for a couple of miles but then stopped charging all of a sudden. I removed the cover off the regulator to find one of the contact points, the first big one, welded shut. I broke them apart, sanded them down and rode for another couple of miles until it happened again. I’m confused as to why it is happening, and wonder if someone can explain to me why they keep welding shut. I’m aware that heat causes this so please save the obvious. I would like to run this setup instead of dropping the cash on a cycle electric voltage regulator bolt on thing if possible.

Should there be more wire length between the regulator and generator to help slow down the charge (don’t think that’s how it works, but…)? Is the heat transfer from the case to the generator and then to the regulator causing it? I’ve seen this setup on other bikes, so I’m skeptical. Anyway, please share your thoughts. Thanks

[Kzac]

The location of the regulator has nothing to do with its operation as long as its properly wired, and your volt drop tests, validate your ground and positive circuits. Remember, unlike transistor alternator regulators used today, generator regulators also control the Amperage output of the generator (your large points)..

Here is a link to the old Delco regulator detail, should get you well on you way.. go back over your wiring.. something there is amiss... verify your Volt drop... for ground and positive...
http://ruiter.ca/mc/info/PDFs/1R-116.pdf

[bustert]

did you polarize the generator?
what will destroy the reg is reverse current. it will cause the contacts to vibrate violently, burning them up and will smoke the series dropping resistor on the back of the reg.
the genny does not care what it puts out but the reg does. on positive ground systems, the reg is diff and will be marked or have diff winding colors.
on the electronic versions, there is a protection diode and current can only flow one way.

[BigMek]

Make sure the regulator is well grounded too. Paint is a lousy conductor, so you might need to run a wire from the regulator to somewhere on the frame/engine. I used one of the front two rocker box bolts and have had zero trouble with it.

[CaptainZoop]

I polarized the generator, yes. And I did make sure to find a good ground on the front motor mount. I will go through my wiring again and see what I can find. I think my battery ground could actually be better since it’s mounted to a tab I welded to the frame and painted for the oil bag.

Originally Posted by Kzac

The location of the regulator has nothing to do with its operation as long as its properly wired, and your volt drop tests, validate your ground and positive circuits. Remember, unlike transistor alternator regulators used today, generator regulators also control the Amperage output of the generator (your large points)..

Here is a link to the old Delco regulator detail, should get you well on you way.. go back over your wiring.. something there is amiss... verify your Volt drop... for ground and positive...
http://ruiter.ca/mc/info/PDFs/1R-116.pdf

Thank you very much for the link, I have a feeling the info in there will sort me out. Cheers

[Kzac]

Remembered I needed to attach the late 60s Sportster wiring diagram
.......

A few old generator things I assumed so I didn't mention, because you seemed to be experienced
1) There are A (ext ground) and B (int ground) type regulators
2) Sometimes generators need to be polarized in order to magnetize the field poles
3) Harleys were 6 V systems until 1965
4) Harley 58 was a 10A max output generator

Check your mods on the bike and make sure they don't add up to more than 10A, when using a generator.

Second focal point (often overlooked), did you remember to put a capacitor in your system (the Cap controls voltage spiking at the contact points). Looking at the 65 Sportster wiring diagram (below) there is a capacitor attached to terminal 61 of the regulator. These were usually 1/2 mf and were referred to on cars as radio noise capacitors. Their real purpose however was to control voltage spike therefore reducing mechanical contact point arching. They were common in older cars wherever contact points were used (Regulators, Distributors, and Relays) You would see them mounted with Regulators, inside the ignition distributor, and at the fuse block, because your blinkers back in those days, had mechanical contacts.

http://www.dansmc.com/wiring_2_1965%...%20Diagram.JPG

[bustert]

To the OP.. you do NOT need this cap..... It is NOT a functional part of the charging system in any way... It is only a high frequency bypass to ground for radio noise suppression.
Its purpose and connection into the circuit in this application does not affect nor control the arcing at the voltage control contacts...
Having this cap in the circuit (or not) will not damage the regulator or affect the charging system in any way.
The capacitor on the GM Delco voltage regulator is ONLY for RFI suppression.. it is not in the "Field" circuit where the altenator field (rotor) contacts are located.
In the days of generator (as opposed to "alternator" charging systems, mis-connecting the RFI capacitor to the field terminal of the generator (an easy mistake to make in the day) would CAUSE a failure of the voltage control contacts in the regulator!! The cap in this particular application was mounted on the generator case, and designed to be connected to the generator "Armature" terminal which was in fact the current output terminal.
GM DELCO used to put a big round red cardboard warning tag on the "field" terminal of the generators telling you NOT to connect the capacitor wire to this (field) terminal! In this instance, the capacitor was being used to suppress the RFI from the arcing at the generator brushes which would be heard as a "whine" on an AM radio..
Of course these two connection terminals were located side by side on the generator case, and only a few of us could read the big red tag. So when this mistake was made the voltage regulator failure would occur within a couple hundred miles.
These uses are NOT related to the use of a capacitor in "Point + Condenser ignition system, where the cap serves an entirely different function in the creation of the High Voltage spark and in fact does absorb the arc at the contacts that is created by the collapse of the field in the primary of the ignition coil on the "break" of the contacts.
Again, I repeat, this capacitor on the Delco Altenator regulator base is NOT involved in the charging circuit in any way, and only exists to suppress the RFI generated by the arcing at the vr contacts... If you look at the back of the regulator base, you will see that the capacitor terminal is merely an extension of the "B" or Battery terminal lug. The capacitor from there to ground suppresses any HF RFI that might be generated from reaching the rest of the car's electrical system and thence being heard as a "popping" type of static on an AM radio..