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ESA yet again and rear shock compatability


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2005 R1200RT w/ESA and 16k miles on the clock.


Recently purchased the bike knowing it had ESA issues, stuck in the two up mode. Figured for the discount I'd take a chance. Took it to the dealer to have them run diags and they said rear shock was toast, saying they tried jumping the shock and it wouldn't respond. They were able to reset the display but said that you could toggle it but the shock won't respond. I wanted to verify myself, just to double check, so when I got home removed the shock and tried it myself. Guess what???? I was able to drive the motor with direct 12v power and lower the pre-load to the bottom of the range(I'm now wondering if the dealer did really jump it even though they charged me). Now however it won't compress the spring, I can hear a slight clunk in the motor when I reverse the polarity but no movement. I could have left it in two up mode as that's 75% of my riding but NOOOOO I had to mess with it.


Question: Is it possible that the ESA pre-load motor could be below a limit that even with direct 12v power would not let it increase pre-load? If so I'm assuming that I need to remove the motor, disassemble and clean and see if it works after that? I've seen a lot of threads but none that I can find where anyone has removed the cover and inspected and/or cleaned it.


In The Meantime: I'd like to buy a used stock non-ESA shock for the rear until I can get this straightened out. I've searched high and low and can't get a good read on the compatibility between the r1200s and non-ESA rear shocks. From what I think it says is that the R(06 - 11), RT(04-10) and even the earlier K1200 GT/RS(02-05) may be interchangeable. I've seen somewhere that someone indicates the GS(05-10) will also work but I don't seem to find that anywhere else. Anyone with knowledge there?





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My ESA shock is in similar shape. Stuck two up, jumper worked for awhile until it didn't, dealer wants about $3K for new complete new unit and electronics update. Basic initial problem was that the preload position sensor (a simple potentiometer) was giving readings slightly out of range, probably a $5 part that is not replaceable. Newer (late '06 and up??) models use a different type of sensor.


The motor unit can be opened, but one of the cover screws is blocked by the spring, so you will need to compress and remove the spring. Not much to see or fix once you are inside. However, the motor engages a hex shaped shaft to change preload. I reinstalled the shock without the motor or cover, and can now manually adjust preload by turning the shaft with a small 1/4" drive ratchet and a very deep socket. Not convenient, but it will do until the damping starts to fade and I upgrade to a non-ESA aftermarket shock.



As best I can tell from the parts fiche at realoem.com, the part number for the non-ESA strut is 33537729295, which was used only on the 2005-2013 R1200RT.

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I was able to replace the rear ESA strut of my 07 that went south at 90,000 km with one from an 08. (Saved a lot of $$$)

It would scroll through all the settings but nothing moved.


There are 2 different ESA from 2005-2013. ESA 1 & ESA 2

They are not interchangeable.

2005-2009 ESA 1 with or without HALL Sensor

2011-2013 ESA 2

2010 can have one or the other depending on build date.


You can see the difference between the two here:


I had to go to the dealer to have the ZFE reprogrammed because the new strut has a HALL sensor and the original one used a potentiometer.


Everything has been working great since (20,000 km ...)


Also. Wilber WESA seems to be a good alternative but only if the shock is leaking. They transfer the motors from the original to the new one.


Great picture BTW

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Morning PCHRT


One of the "fixes" BMW initiated for the early

rear ESA preload problems was to flash a new

firmware that increased the control current

going to the rear drive motor.


I see you used 12volts-- you might first try,

using some penetrating lube on/into the rear

upper spring seat drive mechanism to allow it

to move easier.


THEN, try driving the control motor using 14volts

from your running/charging automobile. (use heavy

enough wires to prevent voltage/current drop when

the motor loads up)

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Thanks Guys...


On motor disassembly, I noticed the screw hidden, found the spring compressor online for $104 just trying to get the gumption to buy it.


I've had a couple of parts sellers on ebay try the procedure for me on their units and out of the two that have tried neither one has worked. So as DR says maybe we just need more juice.


DR I did spray with WD40 initially but I figure that if I take the spring off and get to the motor then there should be no pressure on it when I try the test. if that doesn't work then assume it's toast and I'll look at the first option mentioned and try the 'remote' adjustment. :)


Anyone know if you can use other model rear non ESA shocks?


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So What I've Learned....

My searching never resulted in showing me the innards of the ESA Shock but as you mentioned above I needed to pull the spring to get to the motor cover. Got the compressor and as lkraus outlined not a lot to see but there are some things you can check. With the previous test showing no results in pre-load motor life I wanted to test it unbound, IE remove the shock spring.

Tried that but it still didn't produce any results but still heard the clunk like it wanted to move. So I removed the cover to have a closer inspection. Took off the pedometer (2 bolts) and then removed the motor and unhooked the power lead.

applied power and IT SPINS!!!!

I then tried to move the pre-load drive shaft with a socket as lkraus outlined and it didn't budge, so it looks like its locked up. But here is another oddity, I was able to relieve the pre-load originally with the direct power when the shock wes initially removed from the bike (spring on). During this test the motor didn't move and yet the pre-load is again raised up to almost 2 up position?? WTF????? Stopped here and didn't want to dig much farther as I wanted to at least have a shock on the bike so I could ride it until I figured out my direction. Gonna see if someone will offer up a wasted newer one that I can take the gear housing apart. I also want to see the diff between the two motor sensors.

If anyone else is interested in some naked pictures here are a few of a 2005 Rear ESA shock motor. Sorry for the big pics. :Cool:




Spring off removing the cover, these area torx bits...



Cover Off, that's the pedometer on the bottom of the drive. That and the motor are held on with the 2 allen screws you see:



Pedometer removed:



Motor Removed and ready to test:



Pre-Load Drive Shaft, if not frozed up you can turn it to move the pre-load adjuster:


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