Second Sunday Breakfast today followed by a ride up N. Morgan Territory Rd out by Livermore. For anyone not familiar with the S.F. Bay Area, Morgan Territory Rd is east of the Bay area out by Livermore and its nuclear labs. But the Rd climbs what I think is several hundred feet in height turning from a two lane country rd. to a one lane rd that the ride leader described as "technical". Meaning that if you got off the side you might technically be dead. Actually it's not that bad and we saw at least a dozen bicyclers pumping up it. But it is steep and twisty and there is NO runoff room.

Things were going fine on the ride out and even when climbing up. Beautiful views of the Livermore Valley. But heading down I noticed that the alternator light would intermittently come on dimly. With time the dimness went away in favor of brightly (even in the bright sunlight) on. Thinking at first it might be due to the slow speeds we occasionally would hit in 1st gear, I tried revving the engine to 5000. rpm but without affecting the light., I also noted that when the light was out(Normal) my digital voltmeter indicated 13.2 V but when the alternator light came on the voltage would drop to 11.2 Volts. This continued and I am of the opinion that the heavy pounding the bike was taking was part of the problem. Once we got back down and onto city streets the problem disappeared even on high speed bumps.

Any suggestions of where to start looking?

Well, other than staying off N. Morgan Territory Rd.

Voltage regulator. It's quite possible that the brushes are pretty much worn out. Or maybe just one of them, as happened to me once.

Dai wrote:Voltage regulator. It's quite possible that the brushes are pretty much worn out. Or maybe just one of them, as happened to me once.

That has cross my mind also Dai.
But what is your guess as to be probability of it being the alternator bearings/bushings?
I was thinking of getting the parts and building up a spare alternator. How does one go about estimating if a used alternator is not too worn? I mean the bushings.

So moving right along, I checked my notes. As I have 2 K75's it's best to check the notes. 
Turns out this is the 2nd time this bike has had a similar problem. Last time was 20K miles 
ago and the possible cause was that the alternator main bolt holding the clutch housing/rubber dogs was loose.

So now if I rework the alternator again, i.e. take it out and check the bolt, and the voltage regulator
and brushes I have a question of the assembled experts.

EME shows two variants of part 12 31 1 459 286 (The regulator and brushes unit).

Internal Voltage Regulator - BMW K Bike; 12 31 1 459 286 / EnDuraLast
and
Internal Adjustable Voltage Regulator - BMW K Bike; 12 31 1 459 286 / EnDuraLast

The only discernible difference being that the second is "Adjustable".
Which is appropriate for replacing the regular voltage regulator? 
The VIN decoder shows the bike as a 1990 K75 (no model extension) and EME's fitment
seems to indicate that either is appropriate. Just wondering if there is any difference.

thanks

So far as I know there is only the one for all the K100 and K75.

I have a few of them in my shed [I buy parts as I come across them] and they are simple to replace.

My source over here has been tills.de ...

92KK 84WW Olaf wrote:I have a few of them in my shed [I buy parts as I come across them] and they are simple to replace.

Thanks, and yes I have that part down.

But can anyone give me the secret of how to re-install the alternator with
the rubber nuts? I followed some advice I read somewhere and put a drop of
super glue on the bottom of the rubber nuts to hold them in the cup and have applied silicon
grease to the rubber nuts where the fins slide in. But I've spent two
hours trying to get them to slide together and still no luck putting
the renewed alternator back into place.

Advice and prayers gladly accepted.

J.

jjefferies wrote:. . .the possible cause was that the alternator main bolt holding the clutch housing/rubber dogs was loose.
 EME shows two variants of part 12 31 1 459 286
Internal Voltage Regulator - BMW K Bike; 12 31 1 459 286 / EnDuraLast
and
Internal Adjustable Voltage Regulator - BMW K Bike; 12 31 1 459 286 / EnDuraLast

The rubber nutz are from monkeys. The drivers are dogs. It's one of the most effective cross-species collaborations since the development of mahouts.

Of course, you've verified it isn't a 50 amp alternator installed by some high living sport in the past, and also verified its wiring connections are clean and tight. If you make demands of your alternator with electrical gadgetry—GPS, high-powered driving lights, dance floor strobes, heated clothing, Cuisinarts, Vita Mixers, Ninjas, et cetera—maybe the adjustable is the way to go.

I've submitted a well-browned Beyond Beef Burger currently in digestive process as an offering for your continued well-being and as spiritual guidance for the harmony of your mating alternator parts which might be considered dead nutz relatively soon. Recall, the straps of the rubber nutz touch the floor of the clutch cup, the nutz are placed between the cup vanes, and the slots between them face the axis. Rotate that clutch cup a little then puuuush.

Laitch wrote:

I've submitted a well-browned Beyond Beef Burger currently in digestive process as an offering for your continued well-being and as spiritual guidance for the harmony of your mating alternator parts which might be considered dead nutz relatively soon. Recall, the straps of the rubber nutz touch the floor of the clutch cup, the nutz are placed between the cup vanes, and the slots between them face the axis. Rotate that clutch cup a little then puuuush.

Salaam, Salaam, and may the great grey cat in the sky bless you as well.

Lord, Lord, I pushed and pushed. I offered up incense in the form of silicone wax and have even considered K-Y jelly as a lubricant. The space between the dead nutz seems correct.

BTW, you are aware that there are lines imprinted on the outside of the cup holding the nutz showing where the slots between the nutz are. I assume this is to help align the nutz slots with the vanes/dogs.

Anyway I surrendered to the night and my aching back (from being bent over while push pushing) and covered the tools and parts and went off to In-N-Out burger for delectable goodies for the stomach and to see the delectable goodies for the eyes. Of which there were many tonight. Not sure why. But it almost compensated for my two hours of failure. Tomorrow I shall renew the battle.

jjefferies wrote:BTW, you are aware that there are lines imprinted on the outside of the cup holding the nutz showing where the slots between the nutz are. I assume this is to help align the nutz slots with the vanes/dogs.

It's comforting to know there's a large print edition of those instructions; I just haven't come across it yet. I think it's time for photos of the assembly, j. There might be a spell of heavy gravity impeding the union of these components out in your area that would be difficult to surmount. Photos could possibly clarify the situation.

Castrol red rubber grease. 
Just sayin...

Suzi Q wrote:Castrol red rubber grease. 
Just sayin...

Ok, Ok, so I'm reminded to get back out there and get my fingers dirty - oh did I mention that a neighbor gave me a crate of disposable rubber gloves for caring/watching his cats while they were on Holiday. Well anyway I'm to get off the computer and get back to work.

Where did you and the cats go when they went on Holiday? I'm betting the Canary Islands.

Castrol red rubber grease has the advantage of making you feel like an old time pro. Plus it's super sticky (to hold things in place) and, smearing it on radiator hoses pre-assembly and such like....just feels like an act of love.
One day when I've lost the plot completely, I'm going to spread some on some toast and eat it

Laitch wrote:Where did you and the cats go when they went on Holiday? I'm betting the Canary Islands.

Although to be fair, I had the same problem a few years ago. Apart from copious quantities of silicon grease (bought by the kilo from ebay - jeez but that was a cheap buy!), I used three long M8 bolts to pull the alternator on.

Suzi Q wrote:Castrol red rubber grease has the advantage of making you feel like an old time pro. Plus it's super sticky (to hold things in place) and, smearing it on radiator hoses pre-assembly and such like....just feels like an act of love.

Wish I could find it in the local auto supply stores. No such at least so far. But today I've spent more than three hours trying to get the damned alternator back together and still no luck. I'm almost positive that I've gotten the vanes and the nutz aligned but haven't been bold enough to just tighten the bolts down as I've been told they should just slide together with just a bit of pushing. Think I'm throwing my back out with just pushing.

In my hazy memory I thought I replaced the regulator without removing the alternator.

But I also mastered removing alternators without first removing the starter.

jjeffries wrote:I'm almost positive that I've gotten the vanes and the nutz aligned

I wonder what that feels like.

We need a photo or two of the nuts in the cup, j. Put on your kidney belt, pull out the alternator then photo the assembly ready to install. Be certain there is no wire, dropped sock, toothbrush —or anything else that might have escaped your notice—obstructing the path of the union. I wouldn't tighten the screws unless I was certain it the cup and the driving dog were joined.

By the way, this is no time for wielding your storied hyper-frugality. You might need new nutz in that contraption.

Laitch wrote:

jjeffries wrote:I'm almost positive that I've gotten the vanes and the nutz aligned

We need a photo or two of the nuts in the cup, j. Put on your kidney belt, pull out the alternator then photo the assembly ready to install. Be certain there is no wire, dropped sock, toothbrush —or anything else that might have escaped your notice—obstructing the path of the union. I wouldn't tighten the screws unless I was certain it the cup and the driving dog were joined.

By the way, this is no time for wielding your storied hyper-frugality. You might need new nutz in that contraption.

Well the nutz are new at least unused. Think I picked them up the last time I did this particular operation. In the photo below you can observe the nutz.
Also note that there is an outside line marking the separation of the nutz on the cup.

You can use silicone grease if you can't find rubber grease.
Regards Martin.

I don't know if you are doing this, but I do the following when I install the alternator on my bikes.

First, I align one of the vanes on the drive dog so it is horizontal pointing to the side of the bike.  This makes it easier for me to visualize where it is as I push the alternator into place.

Second, I make longer marks on the cup with a Sharpie pen to make it easier to see where the molded marks are on the cup.  You might also want to mark a vane on the alternator's fan.  This makes it easier to see when you have moved the rotor as you move the alternator into position, knocking it out of alignment.  This is the biggest problem I have when installing mine.

Last, I apply a ton of liquid soap to the knutz and the drive dog.  The more, the merrier.  No big deal because it all washes away with a good rinse when I'm done.

Good luck!

Couldn't figure why the alternator wouldn't just slide on. Decided to try mounting it without rubber nutz. No Go still. Looking at it afresh the primary washer under the nut that holds the cup to the alternator seemed a tad wrong. Tried another alternator - I picked up a couple of spares back in 2000 when Eurotech closed down. Moved the brushes/regulator over, and the nutz and it slid right in slicker than snot on glass. So torqued the alternator into place and am reassembling the bike tomorrow when there's enough light to see me fix several small problems.

Thanks for the advice and prayers.  

BTW, there are three spade electrical connectors on the back of the alternator. Two obviously go to the plug that connects the alternator to the electrical system. But does anyone know the purpose of the third one? It just sits there all by itself alone and not connected to anything. Any thoughts?

J.

jjefferies wrote: Any thoughts?

It's vestigial.

Laitch wrote:

jjefferies wrote: Any thoughts?

It's vestigial.

Your appendix was once considered vestigial, today we recognize that it is the backup haven for your stomach microbes when fever or antibiotics take out the main. So what is this extra spade electrical connector vestigial for ??

Probably a PO mod. Never seen it on any of my bikes.

jjefferies wrote:

Laitch wrote:

jjefferies wrote: Any thoughts?

It's vestigial.

Your appendix was once considered vestigial, today we recognize that it is the backup haven for your stomach microbes when fever or antibiotics take out the main. So what is this extra spade electrical connector vestigial for ??

If I'd known the meaning of the word vestigial when I was ten-years-old, I would have said to myself "It doesn't seem like it" when it became inflamed while I was eating a Bobs Big Burger with my family, then became septic on the way to the hospital, where it was removed. Then I had ice cream.

It does seem vestigial now because after its removal, I don't miss it and exercise plenty of opportunities to climb trees, play sports, try my hand at both low level psychopathy and philanthropy, eat a wide array of junk food without any consequence other than fluctuating weight-gain and poor dentition, and generally be OK. My good bacteria seem to have found a suitable haven elsewhere in my system.

Maybe its seems vestigial because I quit eating meat 13 years later without dire consequences.

Back to your query and Dai's observation. Here's a photo of a 33 amp K100/75 series alternator from Euro Motoelectric. I placed an arrow at what I believe is the source of j's query. Maybe it is a dedicated voltmeter connection or maybe a connection for some bygone starting function but it's vestigial now, by gum. maybe.

Laitch

Back to your query and Dai's observation. Here's a photo of a 33 amp K100/75 series alternator from Euro Motoelectric.

Which raises another question (ok I'm niggling a bit here but curious minds and all that) but all three of my spare alternators, i.e. the ones outside of of a bike read
Bosch 0120339546
G1->14 V 8/32A
Made in Spain
When I go to MAX BMW I don't find that part number
when I go to EME I don't find that part number and the amperage is higher
and it appears that the power takeoffs aren't the plug variety which my bike
uses. Not that I'm looking for a new alternator just trying to figure out what
I've got and what I should be looking at. OBTW, my spare alternators were
obtained from EuroTech back in 2000 when I think they shut down their
Santa Cruz location.

Your pic shows the normal 32/33 amp alternator (pick your source for the amperage figure). The police-spec vehicles were fitted with 50amp alternators (one 8mm thread for the power takeoff and one 6.4mm spade terminal for the control voltage). I think the K1100RT/LT also had a 50amp alternator (not at all sure about the RT). If you really get greedy, it's possible to fit the back end of an R1200RT alternator to the front end of a K1100 50amp alternator and get a whole 864watts/60amps out of it. It's a drop-fit into the K75 and K100, but it does get a bit close to the battery (approx 12mm gap). BTDT just for the sheer hell of doing it...

jjefferies wrote: . . . it appears that the power takeoffs aren't the plug variety
Bosch 0120339546
G1->14 V 8/32A
Made in Spain
When I go to MAX BMW I don't find that part number
Not that I'm looking for a new alternator just trying to figure out what
I've got.

Power takeoffs. Are you trying to run—a corn chopper or woodsplitter, j?
You're unlikely to find Bosch numbers in a BMW parts fiche; you find BMW part numbers; you've posted a Bosch number.
Dai's explained it. What you've got now, presumably, is a working alternator. What more could you want? If there's a next time, you'll likely need to get a 50 amp alternator if you try to buy from EME because EME indicates access to their 33 amp model will be ending.

How accurate is the RealOEM parts fiche if you enter using the bike's VIN?

For my recently aquired K75 RT build date 08/93 it only lists a 50 amp alternator, so should I expect that to be correct?

Tranberg wrote:it only lists a 50 amp alternator, so should I expect that to be correct?

Yes. This image is from MaxBMW's parts fiche in the USA. There is no reason for K75 models in the EU to differ.

Tranberg wrote:How accurate is the RealOEM parts fiche if you enter using the bike's VIN?

For my recently aquired K75 RT build date 08/93 it only lists a 50 amp alternator, so should I expect that to be correct?

I generally avoid RealOEM as it's advertisements drive me wacko crazy. And now it's decided I want the adverts in Spanish. Lovely language but non non. And it shows my machine with a 33Amp alternator for a mere $1021.75. USD. And BTW, I just purchased a needed washer for my bad alternator BMW price $1.14. Price with shipping $5.04. Oh well if I get the right one it'll be worth the effort. As I have 2 spares I doubt I'll be purchasing new any time.

What is that concept "adverts" you talk about? I use Brave Browser, so I'm not familiar with it.

I have noticed other people's computer screens are a lot more cluttered, when I look over their shoulder while they are browsing.

Tranberg wrote:What is that concept "adverts" you talk about? I use Brave Browser, so I'm not familiar with it.

adverts = advertisments