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R12RT starts but shuts down immediately


PNWrider

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Greetings,

 

I have posted most of the following on the BMW MOA website as well.  I am at a loss about what to do next.??  I just replaced the clutch in my my 2011 RT (62,000 miles) and after reassembly of the RT, it will shut down after approximately 1 second even though it easily starts.  
 

1. GS 911 scan performed today shows no codes. 

2. The bike willingly starts and revs up to about 2000 RPM then drops to 700 -800 RPM then quits. all in approximately 1 to 2 seconds. This sequence has been repeated about 8-9 times in the past two days with no changes in the bike behavior. No stumbling when the engine stops - it quits as if the ignition was turned off.  

3. Today I removed all the plastic and fuel tank to check wiring connections, fuel tank connectors, cable routing etc. Attempts to restart resulting in the same 1 second run then quit as before.  I installed the BMW Oetiker bands on either side of the throttle body and they seem air tight.  

During the clutch R&R, the aft half of the frame was removed, the gearbox removed, clutch pack / seals replaced. The throttle bodies were displaced and the two electrical connectors on the top of each throttle body were disconnected. The fuel injector and the throttle cable were not disconnected.  

Seeing as the bike was running well before the clutch R&R, it is seems likely that something was disturbed or disconnected during the clutch R&R. but today, despite going over each connector and doing the GS 911 scan, I have had no success.  Now what??  

I am hoping that someone else on the forum has resolved a similar issue and can offer me some ideas what to check or do next

Thanks
Bill in Tacoma

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7 hours ago, PNWrider said:

Greetings,

 

I have posted most of the following on the BMW MOA website as well.  I am at a loss about what to do next.??  I just replaced the clutch in my my 2011 RT (62,000 miles) and after reassembly of the RT, it will shut down after approximately 1 second even though it easily starts.  
 

1. GS 911 scan performed today shows no codes. 

2. The bike willingly starts and revs up to about 2000 RPM then drops to 700 -800 RPM then quits. all in approximately 1 to 2 seconds. This sequence has been repeated about 8-9 times in the past two days with no changes in the bike behavior. No stumbling when the engine stops - it quits as if the ignition was turned off.  

3. Today I removed all the plastic and fuel tank to check wiring connections, fuel tank connectors, cable routing etc. Attempts to restart resulting in the same 1 second run then quit as before.  I installed the BMW Oetiker bands on either side of the throttle body and they seem air tight.  

During the clutch R&R, the aft half of the frame was removed, the gearbox removed, clutch pack / seals replaced. The throttle bodies were displaced and the two electrical connectors on the top of each throttle body were disconnected. The fuel injector and the throttle cable were not disconnected.  

Seeing as the bike was running well before the clutch R&R, it is seems likely that something was disturbed or disconnected during the clutch R&R. but today, despite going over each connector and doing the GS 911 scan, I have had no success.  Now what??  

I am hoping that someone else on the forum has resolved a similar issue and can offer me some ideas what to check or do next

Thanks
Bill in Tacoma

 

Morning Bill 

 

I haven't seen this before but it is possible due to a few things. 

 

So lets start by having you try to start the engine again. Before starting turn the key to on then allow the dash to fully go through it's boot up.  

 

Then while looking closely at the  booted dash start the engine & see if ANYTHING changes on the dash between engine starting & engine then stalling. (this might give us a direction to look in). 

 

If nothing showing differently on the dash then  you will probably have to rig up a 12v LED (or noid)  to one of the fuel injectors to see if the engine quit is due to loss of fuel injection. 

 

Then rig up a spark gap to one of the  upper spark plugs (between stick coil & spark plug) to see if spark quits at engine quit.

 

And possibly rig up a fuel pressure gauge to see if the fuel pump pressure is dropping out at or just prior to engine stall. 

 

With the 1 second run time that "sort of" points to a fuel rail pressurizing at initial key-on but not staying pressurized after engine start.  (but this is just one of many possibilities)

 

If you have a GS-911 then you should use it to trap the engine data , BMS-K, engine-sensor  data at just prior to engine start, during engine start, & after engine start right up to the point of, & slightly after, engine stall. This might point us to what is changing or shutting down.

 

If you PM me the trapped data then I might be able to spot your problem.

 

Added: now that I think about it  I actually have seen something like this before, the bike had a plugged off exhaust system (guy put a rubber plug in the muffler to prevent water entry when he washed the motorcycle then forgot to remove it). The only difference is I don't think it even ran for a full second  before stall & wouldn't re-fire until it sat a couple of hours.

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Thanks for the quick reply and advice.  I work on the GS911 data capture:  i haven't done this particular operation yet so another opportunity to learn a new skill.  :-)

 

But the first thing will be to check the exhaust flapper assembly - while I do mask off the cylinder intake ports, I didn't put anything in the exhaust tract. However the flap being closed could explain the bikes current malady..  

 

Thanks again,  

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Fuel pump controller bypass did not seem to alter start / run / shutdown sequence.   Ran out of time this afternoon and have a dental appt tomorrow morning but will try bypass again. 

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good evening Dirtrider;

 

I worked on the bike today and finally had some success after several days of no progress.  

 

This afternoon I basically went back to every wiring connector or sensor that had been disconnected or otherwise disturbed during the clutch R&R last week.  Each was inspected, sprayed with contact cleaner, then reconnected.  After that the R1200 reluctantly was able to keep running - about 10 minutes total.  Does not really idle yet but thats tomorrow's project.  

 

While I am happy that the bike is more or less running, I am frustrated that I have little real idea as to what the problem (s) were that caused the no-run issue over the past several days.  Most of the problem is me in that I learned auto mechanics in the late 60s and early 70s in the era of point/coil ignitions and carburetor based fuel systems.  I do not have a head for electronic systems.  

 

Anyways I wanted to thank you for the suggestions especially on the GS911 readouts - By narrowing down the # of engine readouts to ones I thought were important  -  I was more or less able to see that the ECU was working, the fuel pump was ok and there appeared to be ignition spark.   - by tracking down the suggestions I learned more about my R1200 - or least where the components are on the bike and engine.  

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7 hours ago, PNWrider said:

good evening Dirtrider;

 

I worked on the bike today and finally had some success after several days of no progress.  

 

This afternoon I basically went back to every wiring connector or sensor that had been disconnected or otherwise disturbed during the clutch R&R last week.  Each was inspected, sprayed with contact cleaner, then reconnected.  After that the R1200 reluctantly was able to keep running - about 10 minutes total.  Does not really idle yet but thats tomorrow's project.  

 

While I am happy that the bike is more or less running, I am frustrated that I have little real idea as to what the problem (s) were that caused the no-run issue over the past several days.  Most of the problem is me in that I learned auto mechanics in the late 60s and early 70s in the era of point/coil ignitions and carburetor based fuel systems.  I do not have a head for electronic systems.  

 

Anyways I wanted to thank you for the suggestions especially on the GS911 readouts - By narrowing down the # of engine readouts to ones I thought were important  -  I was more or less able to see that the ECU was working, the fuel pump was ok and there appeared to be ignition spark.   - by tracking down the suggestions I learned more about my R1200 - or least where the components are on the bike and engine.  

 

Morning Bill

 

With all that you have had going on your furling computer (BMS-K)  might have some screwed up adaptives causing your idle issues. 

 

So you might try a 20 minute battery disconnect to clear the adaptives,  or use your GS-911 to clear the fueling computer adaptives.

 

There is some debate on if the Camhead 1200 needs a  TPS (Throttle Position Sensor) re-lean procedure but you might do that just to eliminate the possibility.  

 

If you do the battery disconnect mentioned above then right after battery re-connection turn the key on, then without starting the engine,  FULLY open & close the throttle 2 times using the twist grip . Then turn key to off (that's it, if the TPS is learnable that will teach it full closed & full  open throttle position). 

 

Did you manage to trap any data when it was acting up? If so send it to me in Excel format  by PM as I might be able to spot something. 

 

Additional: on your idle problem, make darn sure that the throttle (short) cables are fully seated in the throttle body seats as well as make sure that the R/H short throttle cable is not pulled slightly out of the cable splitter box holding the R/H throttle plate open slightly at idle (or put anther way, make darn sure that both side throttle levers are fully resting in the idle stop screws at idle, especially the R/H side) 

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I did re-set the adaptives several days ago - are you saying that I should do this step again?

 

I'll check the throttle cables as well as the idle stop screws.  

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Do yourself a favour PNWrider and don't adjust the stop screws. Sorry if you already know about this. The screws are set by Bing in the factory and are a royal pain to set again without a test bench.

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7 hours ago, PNWrider said:

I did re-set the adaptives several days ago - are you saying that I should do this step again?

 

I'll check the throttle cables as well as the idle stop screws.  

 

 

Morning Bill 

 

Depends on when you re-set them. If you re-set them after you got it to stay running then you don't need to do it again. If you re-set them before it stayed running on it's own then probably should re-set them again.

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I reset the adaptive settings before I was able to get the bike to run for more than a few seconds.  

 

Plan for tomorrow:

1. check all the cables from the cable splitter box to both of the throttle bodies.  ( I have not touched the idle mixture screws but will locate them to see if the throttle plates are closing all of the way. )

2. Reset adaptive settings.

3.  Redone the throttle learning procedure.  

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Dirt rider: 

Going back to your original reply to my message:

 

I have not seen any changes in the dash readings when I have going through various engine starts.

 

I still haven't been able to do a read out capture of the GS911 - 

 

Bill 

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7 hours ago, PNWrider said:

Dirt rider: 

Going back to your original reply to my message:

 

I have not seen any changes in the dash readings when I have going through various engine starts.

 

I still haven't been able to do a read out capture of the GS911 - 

 

Bill 

 

Morning Bill 

 

Sounds like a solid plan. Have you also looked at your 'idle actuators' (steppers) with your GS-911 to verify that they are getting commanded to move.   Unfortunately you can't tell if the stepper pintles actually move as there is no direct pintle position feedback to the BMS-K (they are only 4 wire steppers so 2 for high & 2 for low with no additional wires  for position feedback).

 

If you put a stethoscope (or long screwdriver to you ear) on each stepper, then turn the key on,  you should be able to hear the pintle move to home (0 position) then motor out  to commanded starting counts. 

 

A GS-911 data log from initial key-on until a minute or so after engine running might  well be worth the effort as it can yield a number of BMS-K inputs & outputs to verify against known parameters. 

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Greetings,  Dirtrider, 

 

This afternoon I reset the adaptive values and did the run up through each gear.  I then did the throttle grip rotation from full closed to wide open followed by ignition off.  The bike is running considerably better but idle speed of around 1800 rpm. It feels like either a trapped cable or an air leak.  

 

I also did a throttle check on the movement of the throttle body cable ends  - very crudely, both throttle plates both move slightly when the handlebar throttle grip is twisted slightly. 

 

Tomorrow, I’ll take the tank off again and check the routing of the throttle cables.  I am going to also open the throttle cable splitter box to see if there is any issues with cable seating. 

 

 

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  • 3 weeks later...

Well, the Christmas holiday is over for another year.  And so back to the important things. The R12 is running well now except for the very high idle issue.  

 

I am assuming that the  left side throttle plate sensor reading (GS911) should be 0% when the throttle is closed.  With the left side throttle cable screwed in to provide maximum cable slack, the GS911 is showing throttle plate position as ~2.75% to ~3.19% with an engine speed at around 2000 rpm and climbing.  

 

If I roll the throttle forward past its "normal" closed throttle position, the idle speed drops to and runs smoothly at the correct 1100 RPM.   The GS911 real time read out for the throttle plate sensor at that point is 0%.  

 

As long as I hold the throttle in its forward position, the bike will run smoothly with no surging or bucking.  As soon as I release the throttle to return its regular idle position, the GS911 indicates that the throttle position sensor shows that the throttle plate is no longer closed at 0% but reverts to the 2.75% to 3.19%.  

 

I have both of the throttle body cables from the throttle cable splitter at maximum slack - no difference in the idle speed characteristics.  

 

I performed throttle idle actuators reset and the adaptive values reset several days ago. I can hear and feel the GS911 performed the actuator reset.  

 

 

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Since only the left side throttle body has a throttle plate sensor that is giving the GS911 reading of 2.75% to 3.19%, am I correct in assuming that the problem of the high idle must be located with the left throttle body?

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On 12/29/2019 at 1:28 AM, PNWrider said:

Since only the left side throttle body has a throttle plate sensor that is giving the GS911 reading of 2.75% to 3.19%, am I correct in assuming that the problem of the high idle must be located with the left throttle body?

 

Morning Bill 

 

It does sound like the problem is on the  L/H side. 

 

With loose cables I'm not really sure what your problem is. 

 

Is the return spring on correctly? Is the throttle cable plastic cam cracked? Is the throttle arm solidly & firmly on the idle stop screw at idle (you need to slide the plastic cover up the cable then  carefully check for this).   

 

IAUQEY0.jpg

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Morning Bill 

 

One other thought!

 

Any chance that you put a rag, or paper towel, or plug in the throttle  body opening during service & that is now stuck in the throttle plate  area preventing full throttle plate closure? 

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A photograph is worth a thousand words! The little b&w photos in the Haynes manual are almost useless. I feel like I can competently assess the throttle cable set up now.  

 

Well as much as I hate to deal with the Oetiker clamps again, I’m going to remove the LH throttle body and inspect it vis. the annotated photograph in Dirtrider’s message.  

 

 

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4 minutes ago, PNWrider said:

A photograph is worth a thousand words! The little b&w photos in the Haynes manual are almost useless. I feel like I can competently assess the throttle cable set up now.  

 

Well as much as I hate to deal with the Oetiker clamps again, I’m going to remove the LH throttle body and inspect it vis. the annotated photograph in Dirtrider’s message.  

 

 

 

Evening Bill

 

You can slide that black plastic cover up the throttle cable, then using a small angled mirror & a good small light look up from underneath using the mirror & light,  you can see most of what I pictured. 

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I released the Oeticker clamps to get a better look at the cable side of left throttle body.  There is a crack in the black plastic that surrounds what appears to be the end of the throttle plate shaft.  I hope the attached photo of my R1200 throttle body showing the crack can be seen as part of this note.  

 

with GS911 connected; the throttle plate sensor connected; observable slack in the throttle cable; no foreign objects in the throttle throat, and the ignition on (not running),  the GS911 real time value is showing the throttle plate at about 2.0+.  A gentle push at the throttle plate bottom edge reveals a slight movement and 0.0% for the GS911 real time throttle value.  

 

It appears that

        the cable is properly routed

        the return springs are in place

        the throttle stop screw is making full contact with the throttle plate arm (the throttle stop screw has not been adjusted).R1200 throttle body

 

 

Is it possible that this crack in the plastic connection to the throttle plate is changing the relationship of the throttle cable to the throttle body plate?  

 

IF this cracked black plastic disc is the culprit, what are the repair options?

 

Thanks.  

 

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I have cracks like that on both cams. I used superglue on them as a temporary fix. So far cannot tell the difference on my bike.

 

You can get new cams from Bing, with or without the shafts. I believe Dirtrider has a nice write-up on this forum about changing the cams with the shafts attached. It is quite involved but not impossible. Have seen one person who reported to have changed just the cams without much trouble.

 

The common line of thought is that these cracks develop from slamming the throttle fully open (no stop on the open end), so it stands to reason that superglue treatment and careful throttle usage would be ok in the short to medium term.

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11 hours ago, PNWrider said:

I released the Oeticker clamps to get a better look at the cable side of left throttle body.  There is a crack in the black plastic that surrounds what appears to be the end of the throttle plate shaft.  I hope the attached photo of my R1200 throttle body showing the crack can be seen as part of this note.  

 

with GS911 connected; the throttle plate sensor connected; observable slack in the throttle cable; no foreign objects in the throttle throat, and the ignition on (not running),  the GS911 real time value is showing the throttle plate at about 2.0+.  A gentle push at the throttle plate bottom edge reveals a slight movement and 0.0% for the GS911 real time throttle value.  

 

It appears that

        the cable is properly routed

        the return springs are in place

        the throttle stop screw is making full contact with the throttle plate arm (the throttle stop screw has not been adjusted).

 

 

Is it possible that this crack in the plastic connection to the throttle plate is changing the relationship of the throttle cable to the throttle body plate?  

 

IF this cracked black plastic disc is the culprit, what are the repair options?

 

Thanks.  

 

 

Morning Bill

 

That crack in the plastic cam is not your immediate problem but  will probably be a future issue if the cracking continues to propagate to the point of other cracks, then the cam disintegrates & falls off the lever. When this happens  you lose throttle control on that side making the bike un-ridable. (it can happen quickly with little or no warning)

 

Both your throttle plate  idle-side stop & the WOT (Wide-Open-Throttle) stop are controlled by that large metal lever under the plastic cam NOT the plastic cam.  (the plastic cam is only there so the throttle cable can move the lever as the plastic cam has no stops built in)  

 

The actual plastic cam is molded around the metal lever & is prevented from slipping or spinning by those 3 divots that you can see in the cam hub face (those 3 divots are molded plastic going all the way through  3 holes in the lever).

 

I really can't tell much from your picture (other than the obvious crack) so the reason for that side not fully returning to 0% is still somewhat of a mystery. 

 

Is the throttle body bore clean (free of coking) in the throttle plate area?  If not then clean it & see if you then get a TPS return to 0%.

 

Are both throttle plate screws tight? If not then re-center the throttle plate & tighten the screws (possibly the throttle plate is off center due to a loose screw).

 

Does the TPS sensor look like it has been moved? Are the screw areas still marked with  undisturbed witness paint? 

 

You can do a TPS adjustment using the GS-911 but I wouldn't suggest doing that UNTIL you figure out WHY that side isn't now returning to 0% TPS. 

 

You probably should plan on addressing that cracked cam at some point in the future (especially if planning a long trip) as once the cracking starts it usually propagates to other cracks then the cam falls off the TB lever.  (difficult to see but there could be cracking on the rear of your cam also). You might also look at the other side throttle body cam.

 

There are choices-- from installing new throttle bodies (very expensive), to sending your throttle bodies to Bing USA (per a phone call to them they JUST press on new levers/cams but do not set or address the possibility of improper air flow at idle due to lever variances, or you can install new cams yourself (no real gain in this over installing new entire cam/with/shaft assembly), or install aftermarket aluminum cams on your existing levers (some have done this but I'm not sure of the long-term durability-- still waiting for some long-term high mile reports on these).

 

Cam replacement procedure thread below (basics)______

 

https://www.bmwsporttouring.com/topic/91991-throttel-body-throttle-shaftcam-install-procedure_/?tab=comments#comment-1020677

 

I have a little more detailed procedure that I can PM you if you decide to replace your cams/shafts. 

 

 

 

 

 

 

 

 

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With the cable dismounted from the cam, GS911 shows the throttle plate returning to 0% reading each time that the throttle arm is released.  

throttle body with dismounted cable.jpeg

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Cable reattached to the throttle body; throttle body is not attached to the bike.

1.  throttle cable adjustment is at maximum slack.

2.  GS911 throttle plate angle readings are variable from 0% to .39% 

 

What is the correct throttle plate angle??  I have assumed it was 0% because the GS911 read out was 0% when the cam stop was definitely in contact with the throttle stop screw.  

throttle cablew attached - throttle body not mounted.jpeg

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throttle body remounted on bike; throttle cable adjustment at maximum slack.  GS911 throttle plate reading consistently at .78% after throttle has been opened then closed.  

 

It appears that the cable is preventing the throttle cam from closing all the way to the throttle stop.  

The throttle cable is not fouled in its route from the cable splitter box to the throttle body.

The cable seats on both the cable splitter box and the throttle body are debris free and cables are fully seated.  

 

It appears that the left side throttle cable is too short - the opposite condition expected from a worn cable.  

 

During the recent clutch R&R, the cable splitter box had to be demounted and moved aside.  It is possible that I did not reinstall it correctly

I will remove the gas tank tomorrow and inspect the cable splitter box.  

Remounted throttle body.jpeg

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Hati - what type of superglue did you use on your throttle body cams?  Tension cracks like the ones on the plastic cam are the most difficult to repair.  

 

 

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Dirtrider - thanks very much for the information about replacing the cams and throttle plates. I will look at the right side throttle body as well.  

 Do know what is the correct  throttle plate angle that would be seen on the GS 911?  As I wrote in the early message today, I don't know what the correct value should be.  ??  

 

Thanks

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2 hours ago, PNWrider said:

 

Hati - what type of superglue did you use on your throttle body cams?  Tension cracks like the ones on the plastic cam are the most difficult to repair.  

 

 

 

It was just a no brand from the local hardware. I did it while replacing the gearbox input/output and balancer shaft seals, as the TBs were already removed. I did give the glue time to dry and it seemed to have stuck ok. The cracks where not all the way from edge to edge, half way in was the worst one from memory. Idea was to stop it from cracking further (as I just bought the bike at the time), so gentle throttle application was not an issue. I am planning to replace the cams though.

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9 hours ago, PNWrider said:

throttle body remounted on bike; throttle cable adjustment at maximum slack.  GS911 throttle plate reading consistently at .78% after throttle has been opened then closed.  

 

It appears that the cable is preventing the throttle cam from closing all the way to the throttle stop.  

The throttle cable is not fouled in its route from the cable splitter box to the throttle body.

The cable seats on both the cable splitter box and the throttle body are debris free and cables are fully seated.  

 

It appears that the left side throttle cable is too short - the opposite condition expected from a worn cable.  

 

During the recent clutch R&R, the cable splitter box had to be demounted and moved aside.  It is possible that I did not reinstall it correctly

I will remove the gas tank tomorrow and inspect the cable splitter box.  

 

 

Morning Bill 

 

That not returning to 0% even with the cable slack is a puzzler. How much fore/aft cable free ply do you have with the cable backed all the way off?  

 

If you don't have good cable free play then your problem could be in the splitter box, but my guess is that it is more likely in the cruise control cable adjuster area. Very easy for the cruise control cable adjuster to pull partially apart during service work therefore partially holding the throttle plates open. 

 

You can just about get to the cruise control cable adjuster without removing the fuel tank as it runs from under the R/H front of the fuel tank to the  cruise control module at the R/H front of frame area. 

 

About mid cable there is an adjuster that can be pulled partially apart (under a sliding rubber boot).

 

Before doing much else maybe try backing the cables off again, then hook up your GS-911, then reach down in to the cruise control cable (in front of fuel tank), then move the cruise cable around fore/aft, up/down while watching the GS-911. If moving (disturbing) the cruise control cable makes the throttle position move on the GS-911 then you might have found your smoking gun. 

 

Throttle Body.jpg

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Dirt Rider,  

Bingo, cruise cable is the culprit.  On my 2011 R12RT, the adjustment portion of this cable is not very accessible - mostly under the glove box.  the end of the cable closest to the cable splitter box had pulled out of the protective rubber boot which effectively reduced the cable length.  ultimately the throttle plate was being held open.  

I'll work on getting the proper slack adjuster for the cruise cable as well as the rest of the throttle body cables that I have undoubtedly have deviated from their correct settings.  

Thank you very much for the suggestion to check the cruise control cable.  

 

Hati,

since my cam disc radial crack goes all the way across, I am thinking of trying to glue some sort of reinforcing piece to the cam itself.  

 

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1 hour ago, PNWrider said:

since my cam disc radial crack goes all the way across, I am thinking of trying to glue some sort of reinforcing piece to the cam itself.  

 

 

I have seen people doing that, never a followup though. Some went to the extent of gluing and pinning the plastic too. Personally I have not seen old age crumble of the cams, which would be my biggest concern. Until such time that I do,  I am comfortable with fixes like these in the short to medium term. Of course you need to be comfortable with that yourself first. Take some photos of your fix, always interesting to see someone else's ideas.

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6 hours ago, PNWrider said:

Dirt Rider,  

Bingo, cruise cable is the culprit.  On my 2011 R12RT, the adjustment portion of this cable is not very accessible - mostly under the glove box.  the end of the cable closest to the cable splitter box had pulled out of the protective rubber boot which effectively reduced the cable length.  ultimately the throttle plate was being held open.  

I'll work on getting the proper slack adjuster for the cruise cable as well as the rest of the throttle body cables that I have undoubtedly have deviated from their correct settings.  

Thank you very much for the suggestion to check the cruise control cable.  

 

Hati,

since my cam disc radial crack goes all the way across, I am thinking of trying to glue some sort of reinforcing piece to the cam itself.  

 

 

Morning Bill

 

Glad that you finally  located the problem. 

 

On gluing anything on the cam, be careful as that cam hub barely clears the spring as the throttle opens & the spring swings across the cam hub.

 

It's also possible the that cam is also cracked on the back side. Once they crack on both sides then they don't stay on the lever long as the camming action splits them off the lever.

 

Before you button it up push the return  spring rubber damper back to the center of the spring as it looks like it has worked it's way towards the  cable end of the bracket.

 

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The cruise control cable apparently is properly reinstalled: the GS911 read out for the throttle plate sensor is still at 0%.  I will go through the throttle synchronization and adaption process again tomorrow.  Hopefully, the idle speed will be steadily at ~1,100 rpm.  Thanks again Dirtrider for pointing out the cruise control cable as the root cause.  

 

Hati and Dirtrider, I did glue a 22mm x 1.5 mm thick fiber disk to the portion of the plastic cam that had the radial crack.  The fiber disc does not interfere with throttle  return spring.    The fiber disc is a extremely tough material - I am hoping it will prevent the further failure of the plastic cam disc.  Photos to follow in a separate message string.  

 

On Dirtrider's suggestion I did inspect the 'back' side of the plastic cam disc and there is a crack in the outer circumference there as well.  

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There is a guy in Tucson that makes metal pulleys that can be fitted or you can get the parts from Bing or send the TB to Bing. Dirt Rider had a thread on it. I was an early adopter of the cracking. BMW as usually said it's the first they heard of it. Until I saw other complaints with the feds. As much as it's nice BMW covers the fuel strip replacement for 12 years from original purchase, the throttle pulleys are a lot more serious problem if you get it, which many will over time. It really soured me. 

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