The information on servicing and adjusting in this posting does NOT apply to the electronic regulators!

STANDARD SYSTEM TEST:
This test is done to ensure that the system, with the voltage regulator bypassed, is capable of producing enough output.
This test is best done with a battery already fully charged, but can be done with a less than full charged battery. With the regulator UNplugged, and D+ jumpered to Df at the regulator PLUG (those are the opposing connections, neither of which has a solid brown wire), as one increases the rpm from roughly about 1500, the alternator will begin to have some output, increasing with rpm increase, and continuing to increase until the alternator system furnishes power to the system, and charging to the battery, to the alternator limits. The voltage, measured at the battery terminals themselves, should rise to near 15 volts.  Do not let it rise above that value.  Since there is no regulator in the circuit at this time, the alternator will try to charge the battery fully, and then try to grossly overcharge the battery, so do not let the motor run at high rpm for more than a couple or three minutes; and do not let the voltage go above 15. This is a standard test for the charging system. Read this ENTIRE posting before proceeding further. If you do not feel competent, do not play with the regulator.

1. REMOVE the regulator from the motorcycle, if necessary pressing the plug connector at the little tab that releases the plug from the regulator. Remove the tape surrounding the can-to-base. Remove the top metal can cover, by prying gently, all around. Position the regulator such that you are looking at a longer side, and the mounting tab is AWAY from you, but at the bottom. That is, the two mounting holes are towards you.

You will see a paper wrapped, hundreds of turns coil, it has an iron core, with a bendable little tab attached at the top. This is really a solenoid, which, when energized enough, pulls downward the metal clapper--the movable metal part, that is above the solenoid, and extends downward on the right side and also has a pair of contacts spot welded to that clapper, one on each side. In other words, the clapper is L shaped (sort of).

On each side of those paired contacts, is a mating contact, these mount, via brackets, into the base of the VR. To the left of the coil is a round item, about 5/16" in diameter, nearly an inch long, probably painted reddish brown, with a wire out each end. This device is a wire wound "choke". It is a special coil of wire, whose main purpose is to reduce some of the electrical arcing at the points. On the underside of the base, is likely a small metal plate, protecting and hiding a couple of resistors. Leave this area alone.

****Saying this slightly differently: At the TOP of the solenoid, as part of the iron core there is a tab, that goes to the LEFT. It is THAT tab that is the VOLTAGE adjustment for the regulator...it is bendable up and down...and only a SLIGHT change will make a LARGE voltage difference. That tab presses against a spring steel blade that is riveted to the clapper. The steel blade extends even farther, to the right, and is then riveted to a sturdy mounting.

***For most folks, simply a slight contacts cleanup and a voltage adjustment by this clapper tab, is all that is necessary.

It is the CLOSED side of the three points that is the 'on' operating side, but all three points should be clean and shiny.

****NOTE: supposedly some of these mechanical regulators were built with a voltage adjuster, on the underside of the unit. It would make adjustment easy...but, if irregularities are found, servicing the contacts may be necessary, as well as adjusting the tab for the correct voltage.

In the REGULATING mode, the clapper contact(s) vibrates between the other two contacts. In one position...the position of at-rest, un-energized condition, the left contacts are closed, and the alternator rotor gets its magnetizing energy at key-on, via the GEN lamp circuit, through those contacts. In the slight to more than slight overvoltage condition, the RIGHT contacts close, reducing the rotor electrical input.

****Note: if the contacts are excessively worn, a new regulator is a good idea. I see no reason an electronic regulator could not be substituted.

Most failures of the mechanical regulator are due to dirty or pitted points. These are cleanable with a thin piece of non-slick paper with a solvent...and if fairly pitted, with quite thin points files.  I use 200 grit only if REALLY bad, then 300, then 400.   I strongly suggest that coarse grit files and coarse grit sandpaper, etc., NOT be used, unless absolutely necessary; and then they need cleaning up with finer and finer grits.   Do NOT do this unless necessary...the least amount of metal removed IS BEST!...I suggest one may want to try a 600 grit silicon carbide paper.

Clean up the points CAREFULLY, and SQUARELY, and do not remove but the tiniest amount of metal.

There are also thin bladed semi-flexible contact burnishing tools at many electronics shops, which come in these very fine grit grades. Many points files are too thick to fit. One can use a narrow strip of fine grit SANDpaper, holding a light pressure and pulling the strip through gently.   Again, I suggest 600 grit silicon carbide paper.  When I do my own voltage regulators I finish the job with 1000 grit or finer....the idea being to POLISH the surface of the points.  Be SURE to clean the points afterwards.....a piece of non-slick paper with ONE drop of a fast evaporating solvent works well.

2. Adjustment of contact spacing is not a good idea. It will upset regulation. However, if considerable metal was removed from the points...not a good idea .... or you have bent things, adjustment may be necessary. The points (contacts) are spaced for both mechanical AND mechanical/electrical reasons. This mechanical VR is more complicated in operation than it appears. The spacing between contacts, the alignment of the clapper, the temperature compensating metals....ETC.

3. Resetting the voltage is done by SLIGHTLY bending the metal tab at the end of the clapper. At room temperature, the voltage should be about 14.0, and higher if colder, lower if warmer. This means that if the engine is hot, and the voltage regulator is also quite warm from the heat rising from the motor, the voltage should be more like 13.7. Be sure to replace cover properly and tape it against ingress of water, etc.

***NOTE: if your battery is not in good condition, you should NOT try to adjust the voltage regulator, as some battery faults will mask any good adjustment attempts.

The FULL procedure/adjustment:::

Most of you will never do the full procedure/adjustment. However, I have set it down, below, and, assuming one has cleaned up the contacts, one can proceed as follows to do a FULL adjustment, rather than simply touching up the voltage. IF YOU HAVE MESSED WITH THE CONTACT SPACING, YOU CAN SIMPLY RESET THIS MECHANICALLY AS FOLLOWS, AND THEN BEND THE TAB FOR THE CORRECT VOLTAGE. IF THE VOLTAGE SEEMS CORRECT ON THE MOTORCYCLE, YOU CAN PROBABLY LEAVE WELL ENOUGH ALONE!

***The very anal lab-type adjustment is shown, for those so inclined. Again...you probably will not have any need to try the full procedure, and simply adjusting the tab after cleaning the points...or....resetting the distance measurements, and then setting the voltage tab...is likely good enough.

 The distance from the solenoid iron core (flat shiny metal) to the clapper, should be perfectly parallel, by critical look-see with your #1 eyeball.... when the clapper, at the top, is depressed with your finger, GENTLY, to its mechanical stop. The adjustment is the RIGHT contact bracket, that rises from the regulator base.

 Release the finger pressure. The air gap at the clapper contact-to-RIGHT contact, should be .012". The adjustment is the LEFT contact bracket, that rises from the regulator base.

 With the regulator mounted to the motorcycle, plugged in, and metal can still off: Reset the voltage regulating point, as described, with the bendable tab. Remember: a SMALL adjustment makes a big difference, and the battery MUST be in good condition and FULLY charged, and the rpm raised enough to ensure the battery is reaching the full charge point after starting the engine....this will take only a minute or so with a previously fully charged battery. If everything is working OK, reseal the can with fresh tape...use the tape rather strongly, so it stretches somewhat....and makes a decent watertight seal from the can to the base.

 *** While most folks will NOT have the necessary test equipment to allow the more rigorous laboratory type testing and adjusting of the regulator...one needs voltmeters, a variable output power supply, resistors, etc. ...the procedure is as follows:

1. Connect a variable D.C. supply (one that does NOT have a lot of A.C. hum riding on the D.C. output...in other words, it is filtered by a capacitor or otherwise), such that the positive (+) output connects to the regulator D+. Connect the negative (-) to regulator D-.

2. Unsolder the choke from Df

3. Connect a thousand ohm resistor...1/2 watt size or larger...from that unsoldered choke wire to an accurate voltmeter (+), and the voltmeter (-) and the other end of that resistor, connect to D-.

4. Connect another of the same type of resistor from D+ to the junction of this voltmeter and the choke wire.

5. Connect another accurate voltmeter across the power supply output. You can use one voltmeter and switch its connections back and forth, but it is better to have two voltmeters...both fairly accurate.

6. Increase the voltage slowly until the left contacts JUST close. That point is measurable by the choke voltage jumping suddenly to a value under 1 volt. Note the supply voltage.

7. DEcrease the voltage until that same point JUST jumps to a level above 12 volts. Note the voltage at the power supply.

8. For normal touring usage, the desired condition is such that:
a. The voltage to close the right contacts is 14.7
b. The voltage to close the left contacts is 13.8

9. Adjust the tension tab so that the average of these two voltages is 14.3, plus or minus 0.1 volt. The average here means to add the two voltages, divide by 2. Bend the adjustment bar a tiny amount and repeat the measurements.

****For those doing a lot of commuting with short cycles of stop and go, it may help to reset things a bit higher. Note that with the following settings and longer touring, you might use up battery water faster. Those with sealed batteries may see less life on your battery. For the commuting type use: right contacts closure at 15.1; left at 14.3; the average value to be 14.7

10. Resolder the choke, replace the cover, replace the tape.

11. Check the battery charging with a voltmeter, on a fully charged battery, using the engine at around 4000 or even 5000 rpm.

Snowbum

ABC#1843
http://bmwmotorcycletech.info