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Alternator Failure Issue (AFI)


Inigo

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It appears that my bike has become a victim of the dreaded alternator failure issue. In my profession, I deal with a thousand acronyms. I might as well add another and call it AFI. I have seen a few postings about this and knew that based on the model year, I might fall into fall into that unlucky parts bin.  I posted this on the BMWLT forum and I am looking for input from this group as well.

R1200RT
Model year: 2015
Production date: 01/2015

The bike started with no problem and I got on the road. There wasn't much traffic so I was able to make good good time. The last few miles before getting to the office, I was on city streets with stop lights. As I pulled in to the parking lot, I noticed the battery symbol had just come on. I checked the voltage and it read 11.9 volts.  There was obviously a problem with the charging system and I was hoping it was NOT the alternator.

When I came back to the bike many hours later, I turned on the bike and checked the voltage, it was 12.2 volts. It had been about 9 hours and the outside temp had climbed 20 degrees so all that made sense. I started the bike and the voltage stayed at 12.2. I looked at the voltage, gave a heavy sigh, and then questioned whether the two Germanic entities that sired this beautiful machine had actually been married.

On the ride home, at slow speeds the voltage dropped to around 11.8 and on the highway and higher RPMs, the voltage crept up to 12.4 volts. Yesterday, I pulled the plug between the alternator and the voltage regulator. I checked the resistance between the legs and also to ground. They all read nearly 0 ohms. Since the stator has 3 independent paths to ground through a long copper wire, the DC resistance should be very small. I then started the bike and checked the voltage between the phases. At 3,000 RPMs, I read 33 VAC, 34 VAC, 0 VAC. This tells me that 1 leg of the stator is shorted together. The voltage regulator is evidently able to make something that resembles DC voltage and current when at higher RPMs but I'm sure it's not very clean or healthy.

I am 95% certain that this is a problem with the internal alternator. I do have the BMW shop manual and I am considering doing the repair myself. I have average/decent mechanical skills but have never cracked open a BMW motorcycle engine case. I know I might be opening up Pandora's box with this question but I will ask anyway. Is this a task that could be accomplished by an average person?

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dirtrider
37 minutes ago, Inigo said:

It appears that my bike has become a victim of the dreaded alternator failure issue. In my profession, I deal with a thousand acronyms. I might as well add another and call it AFI. I have seen a few postings about this and knew that based on the model year, I might fall into fall into that unlucky parts bin.  I posted this on the BMWLT forum and I am looking for input from this group as well.

R1200RT
Model year: 2015
Production date: 01/2015

The bike started with no problem and I got on the road. There wasn't much traffic so I was able to make good good time. The last few miles before getting to the office, I was on city streets with stop lights. As I pulled in to the parking lot, I noticed the battery symbol had just come on. I checked the voltage and it read 11.9 volts.  There was obviously a problem with the charging system and I was hoping it was NOT the alternator.

When I came back to the bike many hours later, I turned on the bike and checked the voltage, it was 12.2 volts. It had been about 9 hours and the outside temp had climbed 20 degrees so all that made sense. I started the bike and the voltage stayed at 12.2. I looked at the voltage, gave a heavy sigh, and then questioned whether the two Germanic entities that sired this beautiful machine had actually been married.

On the ride home, at slow speeds the voltage dropped to around 11.8 and on the highway and higher RPMs, the voltage crept up to 12.4 volts. Yesterday, I pulled the plug between the alternator and the voltage regulator. I checked the resistance between the legs and also to ground. They all read nearly 0 ohms. Since the stator has 3 independent paths to ground through a long copper wire, the DC resistance should be very small. I then started the bike and checked the voltage between the phases. At 3,000 RPMs, I read 33 VAC, 34 VAC, 0 VAC. This tells me that 1 leg of the stator is shorted together. The voltage regulator is evidently able to make something that resembles DC voltage and current when at higher RPMs but I'm sure it's not very clean or healthy.

I am 95% certain that this is a problem with the internal alternator. I do have the BMW shop manual and I am considering doing the repair myself. I have average/decent mechanical skills but have never cracked open a BMW motorcycle engine case. I know I might be opening up Pandora's box with this question but I will ask anyway. Is this a task that could be accomplished by an average person?

Morning  Inigo

 

You ask, Is this a task that could be accomplished by an average person?-- That depends on your definition of the average person.  In my dealing with the public I would say the average person (my definition)  couldn't handle that job without a LOT of help & some amount of luck.

 

But, I would think that a person with average "mechanical skills" should be able to handle it if they take their time & don't try to rush through it.   

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