Throttle_body_cable_pulleys were cracked and replaced

[pwillikers]

Vehicle: 2011 R1200RT (Model: K26, 0440)

 

Based on the experience of others with what seems to be a common failure, I inspected the plastic throttle body pulleys on my Camhead and discovered that both were cracked and had been "repaired" by the previous owner with a blob of epoxy.  YOU SHOULD INSPECT YOURS.

 

 

Not confident in the epoxy repair, I ordered replacement pulleys from ebay and installed them.  There are two threads in the Hexhead section,  here and here, that were of tremendous help in tackling this project.  Please read them before performing this repair.  Big thanks to those who've gone before and documented it for the benefit of others particularly you Dirt Rider. :-)

 

The replacement pulleys are made from an anodized aluminum alloy, not plastic.

 

 

The epoxy repair in plain view

 

Marking the throttle plates to facilitate re-installation

 

The pulleys were cracked on the backside.  I'm really glad I decided to replace them.

 

Removing the old pulley with a mat knife

 

The pulley support flange

 

Test fit of new pulley

 

It needed a very minor bit of filing to be a perfect fit.  Some say it's an interference fit to be pressed together but I couldn't make it work without slight filing of the flange "ears" at the red marks. It is very secure.

 

The flange needs to be drilled to install the new pulley. I used a #28 (or 9/64") drill bit.

 

Repair complete.

 

 

I have a couple suggestions for those who will perform this repair.

 

1. Get the pliers designed to install/remove the earless, low profile band clamps that hold the throttle bodies in place.   I had not seen these specific clamps before and the proper pliers made removing and reinstalling them a cinch.

 

2. When removing the throttle cables from the throttle bodies, don't loosen the 10mm adjustment nuts on the ends of the throttle cables.  The metal barrel that holds the throttle cable in the throttle body will pop right out when the retaining clip is pried open slightly.  You should do this after removing the throttle bodies from the bike and after you've released the cable's end barrel from the throttle body pulley.  (I didn't do this at first and now I'll have to balance the throttle bodies.  Not a big deal but easily avoided.)

 

The garage is my happy place.  :-)

 

[MoPops]

My 2011 RT is just coming up on 30,000 mi.  I’m pretty sure this is not going to be something that I dig into to check.   It’s beyond my mechanical limitations.  
So, with that in mind, what symptoms should I be looking for if I’ve got the cracked throttle bodies?  Or is this a catastrophic failure resulting in a uhaul ride home?   
Thanks

[dirtrider]

11 minutes ago, MoPops said:

My 2011 RT is just coming up on 30,000 mi.  I’m pretty sure this is not going to be something that I dig into to check.   It’s beyond my mechanical limitations.  
So, with that in mind, what symptoms should I be looking for if I’ve got the cracked throttle bodies?  Or is this a catastrophic failure resulting in a uhaul ride home?   
Thanks

Evening MoPops

 

You probably won't notice a thing right up until a cam fails (if you ever have one fail). It's pretty well an instant failure with nothing more than an engine idle remaining. 

[poway]

Excellent write, up thank you!

[LBump]

eBay Link

[Hati]

I bought one of these too. The quality is excellent. I am just waiting for the mileage to come up to service time to fit it.

[6speedTi]

Add another happy customer to the cracked pulley list. Decided to check my pulleys and both sides are cracked. Now I have to make a decision which path to take. Any help would be appreciated.  Thanks.  

 

First photo is right throttle body. 

Second photo is left throttle body.

 

Update, 

Third photo. I just ordered replacement pulleys. 

[pwillikers]

The seller has listed these pulleys on ETSY here.  They're a bit cheaper than on ebay and they're the same product and seller from whom I purchased mine.

[6speedTi]

Hello wonderful BMW motorad riders. I just finished installing both pulleys. I installed the yellow aftermarket ones from Bulgaria. In addition to that I replaced both O2 sensors since they are originally installed from the factory.  My bike is 11 plus years old with 104,000 miles. Thanks to OP pwillikers and dirtriders input all went well. So the pulleys did not fit in the slots. Very tight. So I did some grinding with my dremel on the shaft a bit at a time. Both fit perfect in the groves and centered. Reinstalled the shafts and both throttle valves operate smooth. Both hit the idle stop screw. Do not adjust them. Do not adjust the cable either at this time. Throttle valves go back in without any modification and that's why you shouldn't touch the idle stops. After both valve bodies installed and cables installed on the pulleys that's were you will more than likely have to adjust the cables. One side had slack and the other was pulled off the throttle stop screw. I verified both cable runs were not kinked or binding up against anything and the handle bar is centered. Adjusted both to remove slack and have both throttle valves against the stops. Repeatedly moved the throttle ever so slightly to see both throttles pull together at the same point. Made sure no slack and not too tight to allow for any movement from handle bars. Once I was satisfied with the baseline adjustment then I hooked up my GS-911. Check the TPS reading. 0 at closed throttle.  97 to 98 WOT. 

Did a bunch of tests and resets. Fuel pump and fuel injectors test to check for fuel leaks. I removed the injectors to better handle this project and replaced all orings.

Tested the new O2 heaters. Reset and recalibrated the idle control valves. Cleared adaptations and relearned after the engine was running. At this point, all went well. All tests past. All recalibrations past. Bike started up fine and idle was within specifications. 1,150 +/- 50. I was reading 1,130 to 1,180. Bike ran like I never did anything to it. Next was the throttle synchronization check. I used my twinmax. New 9 volt battery everytime. In case you don't know the twinmax is voltage sensitive. A weak battery will affect the twinmax readings big time. So the "A" side was hooked up to #2 (left) cylinder. And "B" side was #1 (right) cylinder.  Stepper motor plugs disconnected and synchronization showed a pull to the A side about half way between 0 and 1. Sometimes a bit less than half. Checked rpms at 2k, 3k, 3.5k and 4k. Steady needle with slight pull to A side. Reconnected Stepper motors and ran it again.  No difference noticed. In the past with the original pulleys  every time I checked my throttle synchronization with the twinmax it always deflected to the A side about the same as it is now. So maybe I got lucky and it all adjusted properly.  I read somewhere that on the twinmax a slight deflection of less than one on the scale is normal. If I can keep it less than half I'm satisfied. Lots of mechanical movements between the two throttles. 

FYI,  when replacing the O2 sensors I used the O2 sensor socket, soaked the sensors with PBS blaster but ultimately I had to heat the pipes and sensors to break them free using a 1/2 inch breaker bar. 

 

Now as of this post the bike is ready for installation of the fairings then a cross your fingers test ride.  AAA on speed dial. 🤞😅.  I'll add anything else if I forgot to mention in my post.  

Again thanks for the input on this project. 

 

 

[6speedTi]

On 11/14/2023 at 2:17 PM, 6speedTi said:

Hello wonderful BMW motorad riders. I just finished installing both pulleys. I installed the yellow aftermarket ones from Bulgaria. In addition to that I replaced both O2 sensors since they are originally installed from the factory.  My bike is 11 plus years old with 104,000 miles. Thanks to OP pwillikers and dirtriders input all went well. So the pulleys did not fit in the slots. Very tight. So I did some grinding with my dremel on the shaft a bit at a time. Both fit perfect in the groves and centered. Reinstalled the shafts and both throttle valves operate smooth. Both hit the idle stop screw. Do not adjust them. Do not adjust the cable either at this time. Throttle valves go back in without any modification and that's why you shouldn't touch the idle stops. After both valve bodies installed and cables installed on the pulleys that's were you will more than likely have to adjust the cables. One side had slack and the other was pulled off the throttle stop screw. I verified both cable runs were not kinked or binding up against anything and the handle bar is centered. Adjusted both to remove slack and have both throttle valves against the stops. Repeatedly moved the throttle ever so slightly to see both throttles pull together at the same point. Made sure no slack and not too tight to allow for any movement from handle bars. Once I was satisfied with the baseline adjustment then I hooked up my GS-911. Check the TPS reading. 0 at closed throttle.  97 to 98 WOT. 

Did a bunch of tests and resets. Fuel pump and fuel injectors test to check for fuel leaks. I removed the injectors to better handle this project and replaced all orings.

Tested the new O2 heaters. Reset and recalibrated the idle control valves. Cleared adaptations and relearned after the engine was running. At this point, all went well. All tests past. All recalibrations past. Bike started up fine and idle was within specifications. 1,150 +/- 50. I was reading 1,130 to 1,180. Bike ran like I never did anything to it. Next was the throttle synchronization check. I used my twinmax. New 9 volt battery everytime. In case you don't know the twinmax is voltage sensitive. A weak battery will affect the twinmax readings big time. So the "A" side was hooked up to #2 (left) cylinder. And "B" side was #1 (right) cylinder.  Stepper motor plugs disconnected and synchronization showed a pull to the A side about half way between 0 and 1. Sometimes a bit less than half. Checked rpms at 2k, 3k, 3.5k and 4k. Steady needle with slight pull to A side. Reconnected Stepper motors and ran it again.  No difference noticed. In the past with the original pulleys  every time I checked my throttle synchronization with the twinmax it always deflected to the A side about the same as it is now. So maybe I got lucky and it all adjusted properly.  I read somewhere that on the twinmax a slight deflection of less than one on the scale is normal. If I can keep it less than half I'm satisfied. Lots of mechanical movements between the two throttles. 

FYI,  when replacing the O2 sensors I used the O2 sensor socket, soaked the sensors with PBS blaster but ultimately I had to heat the pipes and sensors to break them free using a 1/2 inch breaker bar. 

 

Now as of this post the bike is ready for installation of the fairings then a cross your fingers test ride.  AAA on speed dial. 🤞😅.  I'll add anything else if I forgot to mention in my post.  

Again thanks for the input on this project. 

 

 

UPDATE:

I performed the throttle synchronization using the GS-911 locked stepper motor procedure.

I got the needle closer to center. A very slight deviation to the left (#2) cylinder. Almost perfect. Then did all the resets and recalibrations again.  Ran the engine and it runs very good. 

My suggestion is adjust the cable on the side needed one flat at a time on the barrel nut. I went about 4 flats on the adjustment. 

[pwillikers]

New ebay link from the seller:  https://www.ebay.com/itm/404670769702