The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Semper Gumby on December 09, 2013, 03:45:02 PM
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OK - so I'm having a bit of trouble with my new Euromotoelectric ignition (my fault) and I'm on their website when I see this.
"Permanently Magnetizing your Bosch Alternator Rotor." and the link takes me here -
https://www.euromotoelectrics.com/v/vspfiles/assets/images/permanently%20magnetizing%20your%20bosch%20alternator%20rotor.pdf
Hell yes I have suffered with this problem. Has anybody else had this?
My symptoms are first start of the day the GEN light stays on till about 3000 rpms then after that it stays on till about 2500 rpms.
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I havn't, I posted that link about 3 months ago and it seems like no one else had heard of it either .
I even posted it on a Guzzi forum, the older bikes have the same Bosch charging system as the airheads and no one there had ever heard of it either .
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Well I hunted down and killed the right power supply. It will be here in a few days.
I'll keep you posted. After all this time....could it really be a simple as this :-?
http://www.vetco.net/catalog/product_info.php?products_id=14092&osCsid=buljob0hote1lliomneacoj963
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I see what they are suggesting for permanently magnetising the rotor just don't see why it should be necessary or why the Gen lamp should stay on above idle.
"When running your alternator below 1000 rpm the charging light will stay on. When the bike is revved to 1000 rpm or higher the GEN light will shut off. When the bike reaches 3000 rpm the battery should charge at approximately 13.9Vdc."
That's exactly how mine behaves except I've set the regulator a little higher than 13.9 Volts. The only time that the revs at which the Gen light goes out should increase is if the battery is less than fully charged.
It'll be interesting to hear if magnetizing the rotor makes a difference.
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Hello !
The purpose of the whole system is NOT to have a permanently magnetized rotor... This way, the output of the whole alternator can be tailored to the exact need of the bike and no more (and no less if the system is fit enough). If you permanently magnetize your rotor, the battery will get charged even when full and will, thus, either evaporate it's water or bubble if it's an AGM in both case shorten it's life ... drastically...
As per the charging light, it is wired between the generator output and the battery positive. So it will go out when the battery voltage comes ABOVE the alternator voltage.
This explain why after first cranking the engine (and depleting somewhat the battery with the huge BOSCH starter) the light only goes off at a higher RPM. When the alternator begin to charge, it gives all it's got in current to feed the battery and did not raise it's voltage until the battery recovers somewhat from the cranking. Thus if you have a new big battery and and a perfectly tuned engine, the GEN light will go off at 1500 RPM even after just cranking the engine...
I'm always amazed at how people do not understand automotive electrics and try to "simplify" or "improve" a perfectly designed and efficient charging system (which only flaw is that it was designed for simple and low power electrics of the era)
P.S. : You should check that the GEN light bulb is of the correct wattage to provide the system with sufficient current to get started... Stick with the specified bulb as per BMW instruction and everything should be fine...
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Hello !
<snip>
I'm always amazed at how people do not understand automotive electrics and try to "simplify" or "improve" a perfectly designed and efficient charging system (which only flaw is that it was designed for simple and low power electrics of the era)
P.S. : You should check that the GEN light bulb is of the correct wattage to provide the system with sufficient current to get started... Stick with the specified bulb as per BMW instruction and everything should be fine...
Ah controversy.
1) But I have had this problem for years.
2) I ride year round and I am NOT interested in having to run my Boik at 3000+ rpms when it is -5'C just to get the alternator to "Light Off" first thing in the morning.
3) And recently I tried to put a friends 450 alternator parts on my R65 and it ran normally (light out at about 1500 rpms) so something is amis with the bits that are on my bike and NOBODY can explain it (not even Rick from Motoelectric from whom I bought the 400 watt alternator in the frst place). (The alternator parts would not switch on to his bike because the /6 is a 105mm alternator and the R65 is a 107mm alternator <sigh>).
4) GEN bulb bought from local BMW dealer via an BMW approved part number off a BMW dealer computer. Part number checked with my parts manual for the R65 (march 1980).
So - respectfully - PHIBBIT on you - I'm going to try this. PS - I do understand what you are saying but I'm willing to risk overcharging the AGM battery because I have a voltmeter on my system and if it overcharges then I will see it.
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Georges makes a fair point in that the output of a true permanent magnet alternator cannot be controlled by our type of voltage regulator. So I agree in principle with what he says but I doubt the slight magnetization achieved using the euromotoelectrics method would produce enough output to worry your battery. Once the voltage regulator senses an excessively high voltage it will shut off the current to the rotor leaving only the permanent magnet effect to provide a low level output which I would have thought will be more than consumed by the ignition system.
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I understand the principle of what he is saying.
So I will make a concession and try to get Rick at Motoelectrik to look at the one part in this system that hasn't been changed: the stator.
Then all bets are off and I'm connecting the rotor to the charger. I am frinkin tired of this problem.
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Hello Semper Gumby,
Try to go at an auto part store and get a 12V 3W minimum wedge bulb (5W would be better). And try it on the R65 in a frisky morning.
I frankly doubt that your rotor stay magnetized using the procedure described on the Euromotorelectric web site. After all, it receive this treatment every time the bike runs...
But I was proven wrong many times in my life .... :-?
Depending on the regulator you have installed in the bike, you may be able to adjust it a bit to start charging at a tad lower RPM than the stock.
I, would bet on the bulb being incorrect.
Edit : I doubt that the rotor stays magnetized a long time with the procedure given (not the proper material).
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I've got the 5 watt lamps installed on my '81 R65, I believe it's SAE #194, the OEM lamp is 3 watts, SAE #168 I have not noticed any difference in the charging system operation .
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Yes you're right.
These bulbs are made in 1.2, 2, 3 and 5 watt.
IMHO you need at least 3W to make the system works by the book.
As these bulbs have very faint markings and the difference between a 1.2 W and a 3W bulb is non existent, I suspect some of us have the wrong bulb installed and, thus, need a higher RPM to start the whole system. It is the cheapest thing to change/test... Provided you can find a real 5W bulb ;-)
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For what it's worth I had a similar issue on my 82LS but not quite as severe. First start of the day the light went out at around 2500rpm and then later it would drop to around 1500-1700rpm. I was just living with it since the bike stays on a battery tender when it the garage.
I decided to wire a resistor into the circuit as a backup for one day having a failed generator lamp. Side benefit is that the generator light cuts out right at 1000-1100 rpm ever time now.
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I don't know what you guys are talking about. You have got me chasing after stuff that doesn't exit. The freekin GEN bulb in my R65 is not a #194 or or a #168. It's a tiny thing you can't even get at an Autozone. That's why the last time I bought one I went to the dealer.
Where is my parts manual? >:(
OK - The part number for the bulb that fits in my R65 is 07 11 9 978 375. It is listed as a 1.2 Watt bulb and you are telling me that in order for the Bosch alternator to work properly I need a 3 or 5 watt version of this bulb. Why would BMW sell me a bike with the wrong bulb in it? Are you guys sure on this?
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I understand your frustration. This question seems to be under attack from a dozen different directions. I still think the resistor in the circuit is the way to go. Monte has a great write-up in the Technical FAQ and it literally costs pennies to assemble and install. No question about what bulb, wattage, etc at that point. It puts the exact resistance load needed into the circuit, bulb or no bulb.
I also picked up a solid state voltage regulator at Advance Auto Parts. Generic replacement, just matched it to the old BMW part. Haven't had a charging system hiccup since. Do I know the why and details behind it? Not a chance. But between the two I think I spent about $10 and have never looked back.
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Well believe it or not BMW specified a 1.2W Gen lamp up to 1980 and a 3W lamp from 81. Can't think why they changed it.
A 3W lamp will be approx. 48 ohms so you could try substituting a 48 ohm resistor to see if it makes any difference. You won't actually find a 48 ohm resistor as it's not a preferred value. 47 ohm is commonly available and would be fine.
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Hmmm Monte circuit uses a 330 ohm resistor....
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Hello !
There is a mistake on the various fiche I've looked and they corrected it after a while. 1.2 W is correct wattage for indicators like neutral or high beam or even the oil pressure. But for the gen lamp you need 3 W or more.
So often when one dismantle the tacho for cleaning the wrong bulb get in the Gen position... And problems or funny things start to appear. I bet you may have a 3W bulb in your tacho; somewhere ..
These 5W bulb are often used for parking light on Japanese motorcycle and some BMW too. so you may find one at a Jap dealer... Try Honda. You can get any part of a Honda bike by them. (they even helped me fix my Triumph brake problem, once).
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Hmmm Monte circuit uses a 330 ohm resistor....
That's because the LED bypass resistor doesn't set out to replicate the current draw of a 3W lamp, if it did a high wattage resistor would be needed and it would get too hot. In fact it doesn't even replicate a 1.2W lamp. So the LED/bypass resistor combo passes a lower current to the rotor which by all accounts seems to be enough even though it ought not to be.
All of which is not promising for a 3 W lamp resulting in a cure for your problem. You still got to try it though. When I suggested earlier to substitute a 47 ohm resistor it really is only good for a temporary test because of the excessive heat.
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So a good test in my case would be to put a bulb holder out side of the tacho case and run a 3 or 5 watt bulb in it to see if the alternator lights off earlier...that I can do.
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Georges,
The different gen lamp ratings of 1.2W vs 3W for early/later bikes came from the respective riders handbooks which should be correct but who knows.
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You are not going to believe this.
I read the Snowbum's article on this subject
http://www.bmwmotorcycletech.info/genlampresistor.htm
Not having the right resistor at hand but having a spare bulb holder and wires I rigged up my holder using Method #2 between the hot side of the coil and the DF+ wire into the regulator (Blue Wire),
I've got both lights off at 1250 rpms using a GE90 bulb.
Now I've got to figure out how to make this permanent.
The BMW 1.2 watt bulb doesn't provide enough current to light off the Omega 400 watt alternator!!! Holy Freekin Sh....
So what I really need is a 1981 or later Tachometer so I can put the higher wattage bulb in it. Anybody got one laying about?
So George My Humble apologies - you were right. But a higher wattage bulb for my 1980 Tacho doesn't exist until I can get a later model Tacho. Right now the extra GEN bulb is zip-tied to the air cleaner on the RH side.
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GEN lights on the air cleaner. Next thing you know you'll have neon tubes under the oil pan. [smiley=bmw_smiley.gif] [smiley=laugh.gif]
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Actually I was thinking about what would be a nice 5-7 watt load while stopped at a traffic light. It's got me thinkin' - At least until I find a later model Tachometer.
Seven watts of Neon? More fun than a stuffy old resistor.. That could be a fist full of LED's coming on at idle.
Hmmm ::)
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I will preface this saying I fixed, designed, built and installed electrical stuff for a living for many years. Also I am only on my second cup of coffee and will thus eliminate the math.
Electricity is generated by a wire cutting a magnetic flux line. In our alternators the magnet is in the rotor and the wire is the stator. Bigger magnet and more wires means more electricity generated. Cutting more lines of flux faster (higher RPM) means more electricity.
Euro Moto Electrik sells a permanent magnet alternator. Think refrigerator magnets. They do not need remagnetizing. The
EME system has no brushes.
The Bosh system uses brushes to connect electrical current to the electromagnet in the rotor. The generator light allows a small current flow to the rotor when the switch is turned on causing the alternator to start generating power.
The light going out means there is power being generated, but a digital meter on the battery will indicate the voltage. Until the voltage being generated exceeds the battery voltage, the system is not charging the battery. A 100 watt bulb in the circuit will not make the alternator put out 13.9 volts at 900 RPM.
Snowbum as usual, has many pages of detailed explanation of the BMW charging system. For me I will magnetize my rotor every time I turn on the ignition switch through the generator light just like it was designed.
Bob
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<snip> A 100 watt bulb in the circuit will not make the alternator put out 13.9 volts at 900 RPM.
Snowbum as usual, has many pages of detailed explanation of the BMW charging system. For me I will magnetize my rotor every time I turn on the ignition switch through the generator light just like it was designed.
Bob
Hi Bob,
True. But my tiny 1.2W bulb wasn't enough to energize the system. The added GE 90 is overkill I suspect. So now that I have a properly working system I will find a way to put the right bulb in a different Tachometer and then start reducing the wattage of the bulb until the system starts to not function properly.
And you are right again. This doesn't affect the top end. The system, before and after this farkle, produces about 13.6 volts. But it sure is nice to have that GEN light out at 1250-1500 rpms rather than the 3000+ I was getting before.
BTW - I sent a flurry of emails to Rick at Motoelectrk and he says there are different bulbs that fit (I could not find them only the one that BMW sells) and that as long as the bulb is about 3-4 ohms of resistance the system should work properly. So I'm going to disassemble my tacho and put an ohm meter on that bulb and check it. Then it's off to BMW of Atlanta ohmmeter in hand. Perhaps I don't have to replace the Tach after all.
So the gist of all this is that you don't need to permanently magnetize your Bosch rotor. But you do have to have the right Gen Bulb in the circuit to light off the alternator at a nice low RPM. If you have a system that was performing badly at low rpm as mine was then a Bigger Gen Bulb is may be better! :D
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Bill, any idea what bulb you had in there before .
I got my bulbs at a chain type auto parts store, O'Reilly's, NAPA and I think Walmart has them as well .
I think the 168 and 194 bulbs are the ones you can use, I know the 168 bulbs are the higher wattage bulbs, if it makes any difference or not .
Did a little searching, I found 3 bulbs that have the same T-3 1/4 inch glass base wedge type bulbs .
161 has 2.66 watts .
168 has 4.9 watts .
194 has 3.78 watts .
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BTW - I sent a flurry of emails to Rick at Motoelectrk and he says there are different bulbs that fit (I could not find them only the one that BMW sells) and that as long as the bulb is about 3-4 ohms of resistance the system should work properly
I hope he missed a zero out unless he's talking cold resistance. I guess he must have as the cold resistance of an incandescent lamp is at least a factor of 10 lower than operating resistance
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"A 100 watt bulb in the circuit will not make the alternator put out 13.9 volts at 900 RPM. "
Entirely right, but this 100W bulb will ensure that the alternator gives all it can give at 900 RPM. Even if it is only 1W... If you reduce the energizing current (i.e. place a too low wattage bulb) the same 1W will be obtained at a higher RPM (faster cutting flux lines)... which was the initial problem (the bulb going off at 3000 RPM instead of 1200 ~ 2000 RPM...
So we are right in suggesting to stick with what MM BOSCH and BMW have designed (a stock system with a 3W GEN bulb )
Edit :
I suggest you remove the actual GEN bulb from your bike and check a European car dealer (Porsche, VW, Mercedes, Peugeot, whatever) and ask for the same bulb with 3 or 5 W rating. These bulbs where common on every car of the era as indicator or dashboard lighting so they may be found new somewhere were you are !
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The bulb that is in my bike is different than the bulb you are talking about. It is used in the illumination of Ashtrays in Audis. It is about 1/2 the diameter of the 168 (t3?) bulb you guys are talking about.
I will post a picture.
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Funny, On what kind of bike ? Because all the R45~65 I kow use the wedge 12V 3W bulb.
This may explain the difficulties to find a suitable one.
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The bulb that is in my bike is different than the bulb you are talking about.It is used in the illumination of Ashtrays in Audis.It is about 1/2 the diameter of the 168 (t3?) bulb you guys are talking about.
Gumby has it right.
With nothing better to do I pulled my tacho off the bike and sure enough there are different sizes of lamp in there. 1,2 and 5 are the commonly available 3W wedge type lamps designation W2.1 x 9.5D. 3 and 4 are miniature wedge lamps designation W2 x 4.6D With the aid of a low powered microscope I confirmed that these miniature lamps really are 1.2W
When you look at the picture in an 81 - on manual the lamp holders are the same i.e. 3 and 4 (oil pressure and gen lamps) are still shown as miniature W2 x 4.6D but they are listed as 3W. When I checked an automotive lamps catalogue it seems these miniature lamps are theoretically available in 3W which is a surprise given how small they are. When I looked on line I could only find them in 1.2 W and 2W versions.
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Those smaller bulbs look like the same bulbs that are in the status lights on my Guzzi, charge, oil pressure, high beam, neutral, etc .....
That gives me some motivation to get the resistor installed in the charge light wiring on the Guzzi .
I still have a very dim charge light illuminated, only visable when it's dark when I leave for work .
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The current issue of Airmail, the monthly publication of the ABC, has an interesting article in Airtech written by Oak Okleshen. Oak answers a concern from an '83 R80RT owner who has a very dim GEN lamp that's visible only in the dark.
The article is too long to reprint here in its entirety but I'll present the highlights with the assumption that the battery side in the closed loop of the charging circuit is in good condition. That's good battery, connections all tight and corrosion free.
Oaks states that, when the engine is running, the two sample voltages on either side of the lamp will be close in value but not alike. One may be off a volt or two, allowing the dim bulb glow.
Oak's tips are:
1. Battery charge current is too high. There may be a weak cell in an otherwise functional battery.
2. Fuses. Remove them. Clean fuses and holders. Rotate to insure good contact. (I would add a bit of dieletric grease.)
3. Remove the starter control relay. Clean the relay blades and squirt some contact cleaner into the socket. Not WD-40. Plug the relay in and remove it. Do this several times to insure good contact. (I'm still adding dielectric grease on the blades.)
The individual that had the dim GEN bulb on his R80 went through all of Oak's steps and also installed new fuses. GEN lamp is now totally extinguished while riding. As the R80 owner stated, "I'm not sure what the culprit was."
This is one of those potential fixes that takes a little time and, usually, zero cash. Hopefully, someone may find that Oak's tips will cure their dim GEN bulb.
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THANK YOU BARRY!
If there is a higher wattage version of that freekin tiny bulb I'd love to have it. At the moment I have the GE90 attached to the RH side of my aircleaner. But then if I drop something in the dark with the bike cut off I can now find it! :D
On the plus side of this whole adventure - the hot (+) side of the coil is a great place to wire in a voltmeter. If ever there was a canary in the coalmine for the volts going to your ignition, this is it.
BTW - I can now tell the difference between the Tacho of a 79-80 bike and a 81 and older just by looking at the face of the Tach.
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A tip I saw on the Guzzi site, put o-rings on the metal tangs of the fuse holder, to add extra pressure between the fuse and the holder .