R1200GS LC 2013 alternator swap

Good day to you all!
I was under the impression that the 2013/14 models had the 15 coils alternator, which failed, which BMW update to the 21 windings later, superior model.
The bike in question is a 2013 spring edition, that did not want to charge the battery anymore. The red triangle on the dash, and the indicated voltage was as expected around 10-11V while the bike was idling.

The first thing to do was to check the voltage rectifier, I had another unit that I could swap, but the end result was the same… It meant that the alternator must be failing. Second test was the resistance measurement across the coils, 2 by 2, and ground shortage for the coils. As you might imagine, it indicated a bad alternator…

Now… swapping the alternator on these bikes is not that hard… Just hard to start working on the bike. Once I got it started, I only stopped when the coils were no longer in darkness, and light started to shine over them 🙂

As you might imagine, the sequence would be to remove the fairings(and does the new GS have fairings… it’s almost like a touring bike), remove the fuel tank, drain the oil and coolant, remove all sensor connectors that attach to the engine, remove the engine, remove the gearbox, replace alternator, install in reverse order, fill in fluids and ride into the sunset.

A more detailed flow would be(once fairings and fuel tank removed):

  • coolant expansion tank
  • remove both injection valves/throttle bodies
  • disconnect plug for fuel pressure
  • disconnect O2 sensors, remove the exhaust completely
  • remove the sidestand springs and bolt that hold the springs
  • remove the shifter selector rod
  • remove the upper connector from the starter relay, that one leads to the starter and the starter needs removing
  • remove the alternator cable
  • remove rear brake caliper
  • disengage the final drive so that the shaft drive can be removed
  • remove the shaft drive from the gearbox
  • remove the small arm for the telelever position sensor
  • remove the coolant unit from the top of the engine and the coolant temo sensor connector (these are easier to remove once the engine is lowered, because there is little access, at least for my hands)
  • remove the coolant hoses that connect to the engine
  • inspect all around the engine for cables that have not yet been detached

For lowering the engine, you will need a scissor-like stander and a second set of hands. Take pictures of everything before taking things apart, it will help.

Once the engine is disconnected from the rest of the bike, you will have to add some electrical tape, on the clutch cover and on the right hand side, where the frame could touch it. This is needed so that you don’t scratch the paint of this beautiful piece of jewelry 🙂

The engine comes off in a forward and down movement, diagonally like. Once it is lowered, you will have better access to stuff like starter motor and the clutch slave pump, for removal. You can also remove them once the engine is in position, but if it is lower, it is easier and there is enough clearance, wire length wise.


Put the engine on a working surface and start by taking the front cover off. The clutch needs to be removed, in order for the gearbox to be removed.

The front cover has two of the mounting holes threaded to M8, so you can screw in two bolts, and it will pop off.

Removing the clutch is the next thing to do. I have the special tools to lock the flywheel and the clutch, in order to remove the nut. I am not saying you can’t do it sans the tools, perhaps you can while the engine ison the bike and you can lock it in 6th, but on the workbench, you will definitely need those tools…


Remove the 3 M6 screws, alternatively.


Remove the cover and plates


I have also removed the spark plugs, rotated the engine to TDC compression stroke, so that the larger side of the flywheel locker fitted it, and also fitted the clutch lock tool


That nut sure is tight… I have a 60 cm long bar that I use for loosening it


It is now time for the gearbox to be removed


Keep in mind that if you want to remove the gearbox, you have to rotate the engine, by hand, via the clutch, so that the smaller lock fits into the flywheel (6mm). That would be BDC, if I am not mistaking.


Looks like we are getting close to the issue…


You can see the burnt winding/s now…




The new donor unit


Fit it all back, in reverse order. The small M6 screws all tighten to 10Nm


Fit the engine to the bike, connect it all back and enjoy riding the bike.


If only I can extend a rotating shaft out of this engine and fit a proper alternator, like the previous models had… instead of the permanent magnet type.
I really like the LC bike. Lots of power compared to heaxheads and DOHC, the 1250 is even better. But failures such as this one should not be happening on a bike that costs 24k euros. I understand no bike is perfect, and can accept such failures on a bike that costs 7-8k bought new, but not on these.


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