Throttle Body "MORE" cracked cable cams/pulleys

[greiffster]

2 hours ago, Joe Frickin' Friday said:

 

OK, thanks for the clarification.  

 

You expressed concern upthread about the ability of thicker feeler gauges to adequately conform to the curvature of the throttle bore.  Stacking multiple thin gauges (e.g. a pair of 0.0015" gauges to measure a 0.003" clearance) would facilitate better conformance, but is there some reason not to do this?  I mean maybe we get stackup error if we're trying to come up with an absolute measurement (as e.g. for valve clearance checks), but in this case we just need the same relative measurement before/after the spindle/cam swap, so wouldn't a stack of thin feeler gauges be OK here?

 

Am I correct in understanding that the TPS does not need to be removed from the left TB for this whole job?

 

 

If we're going to use shim stock to ultimately center the plate in the bore, then do we really need the lines on the plate?  I guess we're just using the lines to establish the correct angular orientation of the plate (with respect to the spindle), and we're using the shim stock to establish correct radial position?

 

So the basic procedure I'm gleaning from this thread is this:

 

1. GS-911, record both stepper motor positions for hot-idle.
2. Remove left TB from bike, scratch spindle reference lines on throttle plate.
3. Insert feeler gauges at top and bottom of throttle plate, whatever's needed to almost lift throttle off of idle set screw.  Note required thicknesses.  Also note brightness of flashlight through gap at edge of throttle plate (maybe take a picture?).
4. Remove throttle plate, swap out spindle/cam assembly.
5. Install throttle plate, with screws not quite snug.
6. Adjust rotation of throttle plate (around throttle bore axis) so reference lines are visibly parallel with spindle.
7. Insert same feeler gauges from step 3, tighten throttle plate screws.  (Loctite?  Approx. torque spec?).  Maybe take flashlight pic again, compare to pic from step 3.
8. Put left TB back on bike.
9. Forget/relearn TPS min/max.  
10. GS-911,  check stepper motor positions for hot-idle; should be very close to step one.   If they're not...
11. Repeat steps 2-11 for right TB.

Does all of that sound about right?  

 

Mitch,

You may want to check out this thread as well..........

 

 

[Joe Frickin' Friday]

2 hours ago, greiffster said:

You may want to check out this thread as well..........

 

 

More good detail, thanks.  

[Joe Frickin' Friday]

On 5/1/2019 at 4:52 PM, dirtrider said:

My 09 1200RT also shows 77/47 (with the 47 being very lightly stamped & difficult to see)

 

 

No kidding it's light.  For anyone else wondering what they should be looking for, here's what mine looks like (left side TB, viewed through a mirror, with image flipped for readability and brightness/contrast adjusted):

 

 

The "77/" is thick raised lettering and looks to be a permanent part of the basic casting form, with the "47..." being oh-so-gently stamped after it's cast.  

 

Anyway, I've got parts ordered and an Oetiker tool on the way.  Hope I don't F this up...

 

[greiffster]

Yup..  my “47”’s were barely visible.

[Joe Frickin' Friday]

Hot idle stepper motor check today:

 

 

The two traces are lying on top of each other, moving in sync.  Is this normal?  Seems like there should be a little bit of variation between the two, no?

[dirtrider]

10 hours ago, Joe Frickin' Friday said:

Hot idle stepper motor check today:

 

 

The two traces are lying on top of each other, moving in sync.  Is this normal?  Seems like there should be a little bit of variation between the two, no?

Morning Mitch

 

Normal during some operation, not normal during closed loop, hot engine, curb idle conditions. 

 

Did you just run the motorcycle in place, or ride it for a few miles first. 

 

How long did you run it after engine starting for (this specific) above test? 

 

Were your o2 sensors active & toggling?

 

My personal 2009 1200 usually starts independent stepper control when the engine is warm enough & operated long enough for the stepper counts to be down somewhere around 204 counts. At 132-134 counts your engine might still be too cold, or not run long enough, to go independent. 

[Joe Frickin' Friday]

2 hours ago, dirtrider said:

Normal during some operation, not normal during closed loop, hot engine, curb idle conditions. 

 

Did you just run the motorcycle in place, or ride it for a few miles first. 

 

How long did you run it after engine starting for (this specific) above test? 

 

Were your o2 sensors active & toggling?

 

Ambient temp yesterday was mid 60s.  I went for a five-mile ride, speeds up to 45 MPH with several decel/accel phases throughout.  Bike's temp gauge had reached its usual level by the end, and the engine was behaving as it normally does when fully warmed up.  

 

I parked the bike, took my gear off, hooked up the GS-911 and laptop, and started the bike.  Maybe three minutes elapsed there between shutdown and restart.

 

I didn't wait long after restart before collecting this data.  Maybe as much time as it took to set up the logger, so no more than a minute or so.  

 

Didn't check to see what O2 sensors were doing.    If they're active, is that a good indication that conditions are ripe for checking the stepper motors? Do I need to let the bike idle longer after setting up the GS-911?

 

Plenty of time, parts and tools haven't arrived yet.  I can repeat the test this weekend, with the following:

• a longer warm-up ride (Maybe two five-mile laps on a higher-speed route)
• a longer period of idle on the center stand after returning home
• a check to confirm active O2 sensor cycling before collecting stepper motor data

In the end, it sounds like I should be expecting the stepper motor values to be in the neighborhood of 204 counts, and there should be some degree of variation between left and right.  Does this all sound about right?

[dirtrider]

Morning Mitch

 

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Posted 1 minute ago

  2 hours ago, dirtrider said:

Normal during some operation, not normal during closed loop, hot engine, curb idle conditions. 

 

Did you just run the motorcycle in place, or ride it for a few miles first. 

 

How long did you run it after engine starting for (this specific) above test? 

 

Were your o2 sensors active & toggling?

Read more  

 

Ambient temp yesterday was mid 60s.  I went for a five-mile ride, speeds up to 45 MPH with several decel/accel phases throughout.  Bike's temp gauge had reached its usual level by the end, and the engine was behaving as it normally does when fully warmed up.  -- This should have been long enough for active stepper control.

 

I parked the bike, took my gear off, hooked up the GS-911 and laptop, and started the bike.  Maybe three minutes elapsed there between shutdown and restart. -- If you shut it off then it needs time after re-start to go back into closed loop.

 

I didn't wait long after restart before collecting this data.  Maybe as much time as it took to set up the logger, so no more than a minute or so.  -- You might have to wait longer (look for active o2 sensors)

 

Didn't check to see what O2 sensors were doing.    If they're active, is that a good indication that conditions are ripe for checking the stepper motors? Do I need to let the bike idle longer after setting up the GS-911? -- Possible a longer run time. Active o2 sensors are telling you that it should be  operating in closed loop.

 

Plenty of time, parts and tools haven't arrived yet.  I can repeat the test this weekend, with the following:

• a longer warm-up ride (Maybe two five-mile laps on a higher-speed route)-- Try a longer warmup
• a longer period of idle on the center stand after returning home-- At least a longer warm up after restarting engine
• a check to confirm active O2 sensor cycling before collecting stepper motor data -- Yes, look for active o2 sensors

In the end, it sounds like I should be expecting the stepper motor values to be in the neighborhood of 204 counts, and there should be some degree of variation between left and right.  Does this all sound about right?-- Probably  somewhere around 204 steps +/- is when they should start going independent but a good hot engine, thin motor oil, decent intake air temp etc  then they will probably get commanded lower. Don't fixate on the 204 number as that really has nothing to do with when they go active. It is the engine fueling control & closed loop that determines that. 

 

[Joe Frickin' Friday]

On 3/26/2021 at 9:37 AM, dirtrider said:

Probably  somewhere around 204 steps +/- is when they should start going independent but a good hot engine, thin motor oil, decent intake air temp etc  then they will probably get commanded lower. Don't fixate on the 204 number as that really has nothing to do with when they go active. It is the engine fueling control & closed loop that determines that. 

 

OK, better results today.  ambient temp about 50F, warm- up was two 5-mile loops with top speeds of 65MPH.  Parked, got the GS-911 set up, and watched the lambda sensors.  They were fairly static for a minute or so, and then sure enough, they came to life.  I didn't think they would cool off enough to force open-loop operation so soon after shutdown, but wow.  So here's ~45 seconds of hot idle:

 

 

The lambda sensors appeared to be indicating closed-loop operation, and waddyaknow, the stepper motors were behaving independently, much different from a few days ago.  A bit of drift on stepper motor #2 - started near 85, then drifted down toward 81.   Hm.

 

So if I take my average stepper motor positions for t>=20 seconds, I get 105 for #1 and 81 for #2.  That's pretty different from your values, but I suppose that depends on what I did with my idle air bypass screws the last time I adjusted them, right?  I remember twiddling with them early on in the bike's life, and never again since then.  It seems like the left/right difference might be an indication that I did a crappy job setting the idle air bypass screws so long ago, but I've done eight 6K services since then, and the idle sync (with steppers parked) has always seemed spot-on.  Not sure what to make of that.  

 

Anyway, please let me know if you think the plot represents a valid hot-idle assessment.  If so, I'll start taking things apart.  

[dirtrider]

55 minutes ago, Joe Frickin' Friday said:

 

OK, better results today.  ambient temp about 50F, warm- up was two 5-mile loops with top speeds of 65MPH.  Parked, got the GS-911 set up, and watched the lambda sensors.  They were fairly static for a minute or so, and then sure enough, they came to life.  I didn't think they would cool off enough to force open-loop operation so soon after shutdown, but wow.  So here's ~45 seconds of hot idle:

 

 

The lambda sensors appeared to be indicating closed-loop operation, and waddyaknow, the stepper motors were behaving independently, much different from a few days ago.  A bit of drift on stepper motor #2 - started near 85, then drifted down toward 81.   Hm.

 

So if I take my average stepper motor positions for t>=20 seconds, I get 105 for #1 and 81 for #2.  That's pretty different from your values, but I suppose that depends on what I did with my idle air bypass screws the last time I adjusted them, right?  I remember twiddling with them early on in the bike's life, and never again since then.  It seems like the left/right difference might be an indication that I did a crappy job setting the idle air bypass screws so long ago, but I've done eight 6K services since then, and the idle sync (with steppers parked) has always seemed spot-on.  Not sure what to make of that.  

 

Anyway, please let me know if you think the plot represents a valid hot-idle assessment.  If so, I'll start taking things apart.  

Afternoon Mitch 

 

What air bypass screws? The 1200 only has the base idle screws & the steppers are controlling the air by-pass to keep idle RPM's somewhat constant. (were you thinking of an old 1100 or 1150 motorcycle?)

 

Check the low stepper count side for an air leak between the throttle plate & the cylinder head (or possibly that side was purging during the data capture). If the low side has a cap on the TB nipple then make sure that isn't leaking.

 

Also, make sure the throttle lower cable isn't tight on the low stepper side. 

 

That is more discrepancy than I typically like to see  but if no evap can purging & no intake leaks then it is what it is so you have your baseline. BMW manual gives you 25 mbar (about 10" h2o) difference between sides at hot curb idle as max (I'm not sure what that equates to in stepper counts though) 

 

On the Lambda's cooling off, they are electrically heated so it takes a little time for the lambda heaters to bring them back up to functioning temperature.   

 

Typically I do my above idle balance with the steppers active as that is how the bike is when being ridden.  

 

BMW manual says to take the idle stepper vacuum difference into account then bring that vacuum  off-set  into the above idle balance. 

 

Added: what I have been doing lately is also getting the (pre shaft install)  inches of H2o vacuum delta at HOT ENGINE idle, active Lambda's, with HELD steppers. This is another good verification check after the new shafts are installed.  

[Joe Frickin' Friday]

28 minutes ago, dirtrider said:

What air bypass screws? The 1200 only has the base idle screws & the steppers are controlling the air by-pass to keep idle RPM's somewhat constant. (were you thinking of an old 1100 or 1150 motorcycle?)

 

 

That would explain why I haven't messed with them in a long time.     I remember that was how you dialed in the idle RPM (and sync) on the 1100RT.  

 

29 minutes ago, dirtrider said:

Check the low stepper count side for an air leak between the throttle plate & the cylinder head (or possibly that side was purging during the data capture). If the low side has a cap on the TB nipple then make sure that isn't leaking.

 

 

Do you know which side is #1/#2?  Re: purging the canister, is there a diagnostic setting in the GS-911 where I can temporarily lock that out?  Or maybe just clamp the canister hose with a hemostat, then repeat the measurements?  

[dirtrider]

13 minutes ago, Joe Frickin' Friday said:

Do you know which side is #1/#2?  Re: purging the canister, is there a diagnostic setting in the GS-911 where I can temporarily lock that out?  Or maybe just clamp the canister hose with a hemostat, then repeat the measurements?  

Afternoon Mitch

 

Off-hand I don't remember what side (doesn't matter).

 

On the purge block-off?-- one side will have a rubber vacuum cap & the other side TB will have a hose on the TB nipple (that is the purge side). 

 

Just unhook the hose & put a cap or piece of tape on that side nipple,  voila, you have your purge blocked off. Or just use your Hemostats on the hose.  

 

On my personal 1200 I run a hose up to under the seat from each side TB then cap one side off & hook the purge to the other hose. That way I can easily verify balance without removing tupperware, but more importantly I swap the purge side to side  at each service as that evens out the intake of liquid hydrocarbons if the fuel tank is typically overfilled  (as I usually do but probably shouldn't do)

 

 

 

 

[Joe Frickin' Friday]

 

21 hours ago, dirtrider said:

Just unhook the hose & put a cap or piece of tape on that side nipple,  voila, you have your purge blocked off. Or just use your Hemostats on the hose.  

 

Man this is hard.

 

Tried again today, after having taped off the canister vent port on the left TB (right one is capped).

 

First log was at the max sample rate:

 

 

O2 sensors are active, steppers are behaving independently.  They seem to drift apart in the second half of the game.

 

Immediately after that log was done, I dialed the sample rate back to normal, and logged again:

 

 

The steppers started out in roughly the same positions they were at when the earlier log finished, but after ~12 seconds the #2 stepper succumbed to peer pressure and started marching in lock-step with stepper #1 - and then they both drifted down to around 110.  O2 sensors appeared to be active the whole time, suggesting closed-loop operation.  

 

What's going on here?  

 

 

[dirtrider]

38 minutes ago, Joe Frickin' Friday said:

 

 

Man this is hard.

 

Tried again today, after having taped off the canister vent port on the left TB (right one is capped).

 

First log was at the max sample rate:

 

 

O2 sensors are active, steppers are behaving independently.  They seem to drift apart in the second half of the game.

 

Immediately after that log was done, I dialed the sample rate back to normal, and logged again:

 

 

The steppers started out in roughly the same positions they were at when the earlier log finished, but after ~12 seconds the #2 stepper succumbed to peer pressure and started marching in lock-step with stepper #1 - and then they both drifted down to around 110.  O2 sensors appeared to be active the whole time, suggesting closed-loop operation.  

 

What's going on here?  

 

 

Afternoon Mitch

 

Might not be high enough cylinder head temp or not hot enough oil temp. Is your work area colder today?

 

It does seem to be in closed loop  (Lambda sensor wise anyhow).  

 

You might end up locking the steppers on a hot engine (as warm as you can get this time of year) then putting a manometer on the thing & using the base (locked stepper) cross side delta as the baseline.  

[Joe Frickin' Friday]

10 minutes ago, dirtrider said:

Might not be high enough cylinder head temp or not hot enough oil temp. Is your work area colder today?\

 

Southeast Michigan, so...47 and super windy today.   My warm-up ride was a little shorter than yesterday - 8 miles instead of 11 miles.  Like yesterday, I had a fan blowing on the engine/pipes from the front.

 

Tomorrow's supposed to be better: low 50's, gentler winds.  Will try again with the full 11-mile warm-up and leave the fan off.  My guess is that I'll get values closer to what I got yesterday. 

[Joe Frickin' Friday]

On 3/28/2021 at 2:19 PM, dirtrider said:

Might not be high enough cylinder head temp or not hot enough oil temp. Is your work area colder today?

 

 

Tested again today.  mid 60s, full 11-mile warmup.  No fan on engine during data collection.  Here's what I got:

 

 

For comparison, here's Saturday's test:

 

 

And Sunday's test:

 

I guess the one consistent thing across all three of these days is that the counts for #2 are lower than #1, albeit by a varying amount.  The average delta between the two stepper motor counts over the first twenty seconds is about 22 on Saturday,  6 on Sunday, and 13 today.  A bit of variation, but it seems like if I can do this repair so that the delta is in the same direction (#1 > #2) and by somewhere in the neighborhood of 12-15 counts, then I should be good to go.  

 

Does that seem like a reasonable baseline, or do you think I'm flirting with a $1400 disaster if I go ahead like this?

[dirtrider]

16 minutes ago, Joe Frickin' Friday said:

 

Tested again today.  mid 60s, full 11-mile warmup.  No fan on engine during data collection.  Here's what I got:

 

 

For comparison, here's Saturday's test:

 

 

And Sunday's test:

 

I guess the one consistent thing across all three of these days is that the counts for #2 are lower than #1, albeit by a varying amount.  The average delta between the two stepper motor counts over the first twenty seconds is about 22 on Saturday,  6 on Sunday, and 13 today.  A bit of variation, but it seems like if I can do this repair so that the delta is in the same direction (#1 > #2) and by somewhere in the neighborhood of 12-15 counts, then I should be good to go.  

 

Does that seem like a reasonable baseline, or do you think I'm flirting with a $1400 disaster if I go ahead like this?

Evening Mitch

 

I don't know, that #2 stepper is OK for while then it kind of goes sort of crazy. Problem is you are only seeing COMMANDED stepper position not actual pintle position so if a stepper is slipping a thread or two or is sticky then it will look way out of whack. 

 

I think if it were me I would get a locked-stepper cross side idle balance reading just as a backup baseline (might come in handy later).

 

If you use the feeler stock with precision  (I know that you have that ability)  then you probably won't even need the idle stepper pre-baseline. I did couple of 1200's  with just the feeler stock using precision & care & didn't check them with a GS-911 until way later. They both ran great afterwards & looked good on the GS-911 later. 

 

Is there any chance that you (or somebody) moved a base idle screw at one time?) --How close is the locked stepper hot engine  idle balance???????  If the hot engine locked-stepper balance is fairly close then personally I would go ahead with the job & not worry.

 

If the locked stepper balance is way off then THAT needs to be understood before proceeding.  

 

You aren't gong to brick your throttle bodies as they are always adjustable afterwards if needed & if the feeler stock procedure is done correctly then the TB's should be very closed side to side based on that throttle valve gap air-flow.  

[Joe Frickin' Friday]

2 hours ago, dirtrider said:

Is there any chance that you (or somebody) moved a base idle screw at one time?) --How close is the locked stepper hot engine  idle balance??????? 

 

Dealer only did the 600-mile check; the rest of the service has been done by me, and I never messed with the base idle screws.  

 

I don't have a manometer handy, so I'm hard pressed to measure the hot-idle balance in actual inches of water.  Best I can do is a TwinMax, and just make a note of how far the needle's mean position deviates from zero when it's set to max sensitivity.  Will try this tomorrow.  Supposed to be colder weather (50F), but I don't think that'll matter for this test.

[dirtrider]

10 hours ago, Joe Frickin' Friday said:

 

Dealer only did the 600-mile check; the rest of the service has been done by me, and I never messed with the base idle screws.  

 

I don't have a manometer handy, so I'm hard pressed to measure the hot-idle balance in actual inches of water.  Best I can do is a TwinMax, and just make a note of how far the needle's mean position deviates from zero when it's set to max sensitivity.  Will try this tomorrow.  Supposed to be colder weather (50F), but I don't think that'll matter for this test.

Morning Mitch

 

A TwinMax is better then nothing & should work for a baseline. You are really only interested in recording the vacuum delta at held-stepper hot engine idle.  

 

If your base idle screws have never been touched then you might have some coking in the stepper pintle or air-bypass passage  areas.  

 

Also, when you have it apart look closely for any possible cracks or leaks in air boots between the throttle bodies & the cylinder head.   

 

 

[Joe Frickin' Friday]

20 hours ago, Joe Frickin' Friday said:

Will try this tomorrow.

 

So much for "tomorrow" (today).  Can't find the tubes for my TwinMax.  Ordered some more tubing from McMaster today, should be here tomorrow.  Except tomorrow's high is in the mid 30's.    Looks like I'll be getting a baseline vacuum differential on Friday.  Stay tuned...

[ed may]

Replying to Dirtrider

"After you get a few hundred miles on that bike can you do another hot engine  idle stepper position check (check right after the long ride before engine has a chance to cool off).

I'm curious to know where your commanded stepper counts end up after they settle in & re-learn. "   

Sorry I haven't done this yet, been busy and the weather has been rough.  I will do this the next time I take it out.   I am slightly concerned with my one side being so much lower, at 18, but it ran great.  My concern is that stepper bottoming out at zero if it tries to bring the idle down further than when I checked it.  Different ambient conditions may require that, but hopefully not.  It's in the 30s today, bike in the garage, board computer shows 46 degrees, it started perfectly and settled into a smooth idle.  Hopefully I'll get a nice ride in this weekend and check those numbers for you.

 

[Jeffrop]

Hexhead Gurus,

Here’s my issues with my 09 r1200 rt with 49,900 miles

 

Left side cam was cracked so replaced with new pulley and shaft from Bing. 

Do not have a GS-911

Followed and reread this thread many times so my small brain could understand. 
Used .015 “ feelers for top/bottom of throttle body plate

Used .015” for the idle screw gap.

Cleaned crud in the body with carb cleaner and rag; staying away from any electrical connection or sensor. 
Marked the TPS
Did the relearn by disconnecting battery + for two minutes and did throttle twist twice.

Reassembled and bike started up but as it warmed, has a very rough idle😡

 

Disassembled and found the two plate screws loose and plate off the marks-likely operator brain cramp.  Re-aligned the plates (.015”) and tightened screws, compared the light halo to original pix.  Did relearn again (since the TPS was disconnected) and waited 5 minutes before throttle twists.

Still have the rough idle 🤬

 

Removed all Tupperware again and will go over all steps again.  What am I missing?
 

is it possible the left TB clean and the right TB is untouched/ dirty,  is causing the rough idle?  Should the idle be adjusted?  Will be checking for cracks in the air boots and probably clean right TB
Power/ acceleration is the same when riding but did notice a slight “surge” when chopping throttle off- could be imagining that?

[Joe Frickin' Friday]

I replaced my left-side throttle spindle yesterday.  I messed up and removed the brass throttle plate without marking its alignment with the spindle.  Oops.  Got it all back together, and although it seemed to run OK afterwards, there was a measurable change in air flow.  

 

Before the job, my TwinMax recorded this (at max sensitivity, and needle returned to zero after turning off the engine):

 

 

The needle was pointing toward the right cylinder, indicating stronger vacuum over there, but only a smidge.

 

After replacing the left throttle spindle, I warmed the bike up and checked again (again, max sensitivity and needle returned to zero after turning off the engine):

 

 

Needle points toward vacuum, so after my work, the left-side throttle was letting more air in than before.  The official BMW service manual says a differential of 25 millibar (10" of water) is the max allowable at idle.  I don't know how the numbers on the display correspond to pressure differential (obviously this varies depending on how you set the sensitivity knob).    I have some clear tubing lying around, so I'm going to check my TwinMax to find out.  

 

Even if the differential I have is beyond BMW spec, it's probably not by much.  The bike still runs fine as far as I can tell, and of course I don't know how this will settle out until I service the right TB.  Who knows, that might move the needle in a good direction.  

 

@Jeffrop, your symptoms (rough idle but OK at power) are consistent with the throttle being held open on one side when at idle.  Two reasons for this.  The most common, any time someone messes with the throttle cables, is that the cable housing is not full seated during reinstallation.  The other one, unique to this job, is that your throttle pulley has a new cable groove on it that's missing 50,000 miles of wear.  When I first put my bike back together yesterday, and exercised the throttle grip, I found that the left throttle wasn't coming all the way to its idle stop.  I had to loosen that cable a bit, until I could hear both throttles clacking on their stops when I rolled off the throttle.  So don't take your bike apart just yet - check to make sure that left throttle is hitting its stop when you roll off the throttle grip.  If the cable housing is full seated,  then try working the cable housing adjuster to get some slack on that side.  You'll screw up your left-right cable sync which might make it run funny under load, but you'll be able to get an honest assessment of idle.

[Jeffrop]

Mitch

thanks for the tips.  Had already reassembled and found one issue that I thought was the cause-the spring clip on the TPS side was not fully seated in the shaft groove so I though that was the issue (allowing shaft to slightly bind).  Just got back from a test ride and it is slightly better but nowhere near the original smooth idle.  Will check out the cable housing and throttle stop later tonight and will report results

[dirtrider]

2 hours ago, Jeffrop said:

Hexhead Gurus,

Here’s my issues with my 09 r1200 rt with 49,900 miles

 

Left side cam was cracked so replaced with new pulley and shaft from Bing. 

Do not have a GS-911

Followed and reread this thread many times so my small brain could understand. 
Used .015 “ feelers for top/bottom of throttle body plate

Used .015” for the idle screw gap.

Cleaned crud in the body with carb cleaner and rag; staying away from any electrical connection or sensor. 
Marked the TPS
Did the relearn by disconnecting battery + for two minutes and did throttle twist twice.

Reassembled and bike started up but as it warmed, has a very rough idle😡

 

Disassembled and found the two plate screws loose and plate off the marks-likely operator brain cramp.  Re-aligned the plates (.015”) and tightened screws, compared the light halo to original pix.  Did relearn again (since the TPS was disconnected) and waited 5 minutes before throttle twists.

Still have the rough idle 🤬

 

Removed all Tupperware again and will go over all steps again.  What am I missing?
 

is it possible the left TB clean and the right TB is untouched/ dirty,  is causing the rough idle?  Should the idle be adjusted?  Will be checking for cracks in the air boots and probably clean right TB
Power/ acceleration is the same when riding but did notice a slight “surge” when chopping throttle off- could be imagining that?

 

 

Afternoon Jeffrop

 

Tell us that you didn't use actually .015" (fifteen thousandths feeler stock)? 

 

You need to use  .0015"  (fifteen ten-thousands ) feeler stock, that is only one & half thousandths.

 

After you verify that you used the correct feeler stock, & verify that you don't now have tight cables, then next  you probably need to get a manometer on that motorcycle to see what your warm engine cross side idle balance is.

 

Then we can go from there.  

 

 

[dirtrider]

1 hour ago, Joe Frickin' Friday said:

I replaced my left-side throttle spindle yesterday.  I messed up and removed the brass throttle plate without marking its alignment with the spindle.  Oops.  Got it all back together, and although it seemed to run OK afterwards, there was a measurable change in air flow.  

 

Before the job, my TwinMax recorded this (at max sensitivity, and needle returned to zero after turning off the engine):

 

 

 

The needle was pointing toward the right cylinder, indicating stronger vacuum over there, but only a smidge.

 

After replacing the left throttle spindle, I warmed the bike up and checked again (again, max sensitivity and needle returned to zero after turning off the engine):

 

 

 

Needle points toward vacuum, so after my work, the left-side throttle was letting more air in than before.  The official BMW service manual says a differential of 25 millibar (10" of water) is the max allowable at idle.  I don't know how the numbers on the display correspond to pressure differential (obviously this varies depending on how you set the sensitivity knob).    I have some clear tubing lying around, so I'm going to check my TwinMax to find out.  

 

Even if the differential I have is beyond BMW spec, it's probably not by much.  The bike still runs fine as far as I can tell, and of course I don't know how this will settle out until I service the right TB.  Who knows, that might move the needle in a good direction.  

 

 

Evening Mitch

 

There is high possibility that you do not have the throttle plate clocked exactly as it was before removal.

 

It is what it is now so you will either have to live with it or try to correct the air flow.

 

If you need to correct the base air flow using a throttle plate re-clocking then you will probably have to back the base idle screw out about 2 full turns  (should be very precise on the back-out from it's present position). Then loosen the throttle plate screws a little, then while working the throttle lever try to get the oval throttle plate to find a natural sealing in the throttle bore  all the way around.   Then while holding the throttle closed on the best sealing throttle plate condition tighten the screws.

 

Then turn the base idle screw exactly back to where it was.

 

Also, make darn sure the throttle shaft is centered laterally so no air can leak around the recess at one end of an improperly centered  throttle plate.

 

Get the other side done (be sure to mark the throttle plate clocking). Then I would suggest that you make a nice cheap little liquid  U tube manometer so we can see what you are dealing with in inches of H2o. 

 

  

 

 

[Jeffrop]

DR

Good catch- .0015” was used🤦‍♂️  
 

will use all the suggestions then put it on my manometer tonight or tomorrow morning and will report findings. 

 

Hopefully will get this corrected and thanks for all the info-this site is my go to for anything BMW!

[Joe Frickin' Friday]

14 hours ago, dirtrider said:

Get the other side done (be sure to mark the throttle plate clocking). Then I would suggest that you make a nice cheap little liquid  U tube manometer so we can see what you are dealing with in inches of H2o. 

 

 

I made a manometer yesterday so I could calibrate my TwinMax.  I found that on max sensitivity, a reading of '2' on the display corresponded to about 18 inches of water.  Which means that after my first TB, when I read this:

 

 

my imbalance was about 22-23 inches of water, more than twice the allowable spec (10 inH2O).  Must be a pretty tight spec, because the bike still seemed to run good.

 

I replaced the throttle spindle on the right TB last night (this time I marked the plate to assure correct clocking).  Hopefully later today I'll get it back in the bike and see how it runs.  If I'm lucky, then the right side will be letting more air in than it used to, pushing the balance back toward zero.  if not, well, I guess I'll be redoing the left TB.  

 

When working on the right TB last night, I noticed there were pretty good witness marks on the forward face of the plate.  The left throttle plate probably has similar marks, so if do have to rework the left TB, I might have a good clocking reference already.  

[Jeffrop]

I repositioned the throttle plate and used existing witness marks (good tip, Mitch) and, did a relearn and, after warming up, this improved idle by 50%.
Checked/removed the throttle cable, housing and adjuster clip and all was tight.  Thought I was missing a clip for the cable housing at the distribution box (there is a groove in the housing) but parts catalog did not show one.  Took a qtip with a little carb cleaner and cleaned the idle screw adjuster tip.  Turned the idle adjust screw in about 1/16 turn to increase Idle slightly and now  much smoother, dare I say as smooth as before? Anything else I should do?

 

Took bike out for a 60 mile  test ride and turned bike off/on several times and idle is very smooth and no discernible difference in power.

 

I do want to put the manometer (see pix)  on to check the idle cross balance and plan on doing that when I do  the TBS, valve check,  and fluid changes in about a 1000 miles.  Do I have to use H2O or can I use the 2 stroke oil that I use for TBS?  If water is required, I will just get another section of tubing so I will have both available

 

DR and Mitch-can’t thank you enough for all the guidance, suggestions and education!

 

 

 

 

[Joe Frickin' Friday]

10 hours ago, Jeffrop said:

Do I have to use H2O or can I use the 2 stroke oil that I use for TBS?

 

You can use oil; we'd just need to convert the units from inches of oil to inches of water.  Mobile 2-stroke oil has a specific gravity of 0.866,  so take your inches-of-oil measurement and divide by 0.866 to get inches of water; that'll let you compare to the 10 InH2O spec in the manual.

[dirtrider]

11 hours ago, Jeffrop said:

I repositioned the throttle plate and used existing witness marks (good tip, Mitch) and, did a relearn and, after warming up, this improved idle by 50%.
Checked/removed the throttle cable, housing and adjuster clip and all was tight.  Thought I was missing a clip for the cable housing at the distribution box (there is a groove in the housing) but parts catalog did not show one.  Took a qtip with a little carb cleaner and cleaned the idle screw adjuster tip.  Turned the idle adjust screw in about 1/16 turn to increase Idle slightly and now  much smoother, dare I say as smooth as before? Anything else I should do?

 

Took bike out for a 60 mile  test ride and turned bike off/on several times and idle is very smooth and no discernible difference in power.

 

I do want to put the manometer (see pix)  on to check the idle cross balance and plan on doing that when I do  the TBS, valve check,  and fluid changes in about a 1000 miles.  Do I have to use H2O or can I use the 2 stroke oil that I use for TBS?  If water is required, I will just get another section of tubing so I will have both available

 

DR and Mitch-can’t thank you enough for all the guidance, suggestions and education!

Morning   Jeffrop

 

Personally I prefer water as it is more active & doesn't stick to the sides of smaller diameter tubing. Due to the harsher  power pulses of the large piston BMW 2 cylinder engine you will probably find that the fluid column dances in the tubing at curb idle.   Either will work, (personally) I just prefer the finer detail when using H2o. 

 

Be sure to totally clamp off one side hose going the throttle body (hemostats, small vice grips, little C clamp, even a pair of needle nose pliers with a Zip tie across the handles or across the needle tips)

 

THEN, once the engine is started & idling good SLOWLY start releasing the clamp-off & allow the fluid to start responding. (this can keep you from sucking the fluid out of the tube during engine starting).  As you slowly release the clamp-off  if the fluid on one side starts raising too far then STOP,  re-group then figure out why that is happening!

 

[lkraus]

I use water just because it has less potential for making a mess if the manometer gets tipped over. For storage, blow the water out when finished, refill next time it's needed.

Water and light oils show much smaller changes than mercury or the electronic devices I've seen. Nudge the adjuster and a meter might move a hard-to-detect needle width while the same nudge will cause a water column to move an inch.  I can get the water columns within 2 inches easily, and within one inch with a bit of patience. It takes some trial and error to compensate for the tiny change made by the final tightening of the lock nut.

[dirtrider]

18 minutes ago, lkraus said:

I use water just because it has less potential for making a mess if the manometer gets tipped over. For storage, blow the water out when finished, refill next time it's needed.

Water and light oils show much smaller changes than mercury or the electronic devices I've seen. Nudge the adjuster and a meter might move a hard-to-detect needle width while the same nudge will cause a water column to move an inch.  I can get the water columns within 2 inches easily, and within one inch with a bit of patience. It takes some trial and error to compensate for the tiny change made by the final tightening of the lock nut.

Morning Larry

 

Larry said ___Water and light oils show much smaller changes than mercury ___

 

Something really wrong with this statement___ as there are 13.6 inches of H2o to equal 1 inch of Hg (mercury). So water is WAY more active & shows way more changes than mercury.

 

What isn't even a blip on a mercury gauge can move a water column 2 or 3 inches.

 

That is why most of us that prefer & seek precision use plain old H2o. 

 

 

[Jeffrop]

Looks like water is the one to use, so I can stay away from the math🤔

Thanks

[dirtrider]

2 hours ago, Joe Frickin' Friday said:

 

You can use oil; we'd just need to convert the units from inches of oil to inches of water.  Mobile 2-stroke oil has a specific gravity of 0.866,  so take your inches-of-oil measurement and divide by 0.866 to get inches of water; that'll let you compare to the 10 InH2O spec in the manual.

Morning Mitch

 

"so take your inches-of-oil measurement and divide by 0.866 to get inches of water"

 

Are you sure, oil floats on water so it is lighter. Therefore oil will raise higher in the tube for the same vacuum  input.  So we can assume that for the same vacuum input the inches of oil would be higher than inches of water.

 

  If you divide  10 inches of oil by .866 that give you  11.54 inches of water (should be lower not higher as water weighs more the oil).

 

[Joe Frickin' Friday]

34 minutes ago, dirtrider said:

Are you sure, oil floats on water so it is lighter. Therefore oil will raise higher in the tube for the same vacuum  input.  So we can assume that for the same vacuum input the inches of oil would be higher than inches of water.

 

  If you divide  10 inches of oil by .866 that give you  11.54 inches of water (should be lower not higher as water weighs more the oil).

 

My bad, you're right.  an inch of water is more pressure than an inch of oil, so one inch of water = 0.866 inches of oil.  Good catch.

[dirtrider]

2 minutes ago, Joe Frickin' Friday said:

 

My bad, you're right.  an inch of water is more pressure than an inch of oil, so one inch of water = 0.866 inches of oil.  Good catch.

Morning Mitch 

 

Shouldn't that be  --  1 inch of OIL = 0.866 inches of water. Or put another way, 10" of oil equals 8.66" of water.

 

The more we think about this about this the more confusing a simple problem gets. 

[Joe Frickin' Friday]

45 minutes ago, dirtrider said:

Morning Mitch 

 

Shouldn't that be  --  1 inch of OIL = 0.866 inches of water. Or put another way, 10" of oil equals 8.66" of water.

 

The more we think about this about this the more confusing a simple problem gets. 

 

 

I should probably just stop typing now.

 

 

[Joe Frickin' Friday]

22 hours ago, dirtrider said:

Larry said ___Water and light oils show much smaller changes than mercury ___

 

Something really wrong with this statement___ as there are 13.6 inches of H2o to equal 1 inch of Hg (mercury). So water is WAY more active & shows way more changes than mercury.

 

What isn't even a blip on a mercury gauge can move a water column 2 or 3 inches.

 

That is why most of us that prefer & seek precision use plain old H2o. 

 

I think what Larry meant was that water is useful for detecting much smaller changes in pressure than mercury.  You guys are on the same side.  

 

On 4/6/2021 at 7:28 AM, Joe Frickin' Friday said:

I replaced the throttle spindle on the right TB last night (this time I marked the plate to assure correct clocking).  Hopefully later today I'll get it back in the bike and see how it runs.  If I'm lucky, then the right side will be letting more air in than it used to, pushing the balance back toward zero.  if not, well, I guess I'll be redoing the left TB.  

 

Got the right TB back on the bike on Tuesday, and checked things out yesterday.  The results are, um, interesting.  

 

On the plus side, the TwinMax says vacuum balance at idle (with steppers disabled) is miraculously perfect.  Better than it was before I started the whole project.  Whatever I did to the left side to make it let more air in, somehow I managed to also do to the right side. The bike idles and runs great.

 

On the minus (or may be just "huh, that's weird") side, the stepper motors don't behave like they used to.  This is the data from yesterday:

 

 

This was after a good warm-up ride, on a good warm day (upper 70s yesterday).  For this log, I didn't actually start the engine until about t=4 seconds, and you can see a couple of periods (20-40 seconds and 55-65 seconds) where I was twisting the grip a bit to try to warm up the O2 sensors faster.  Even so, sensor #1 never really went active, and the two stepper motors never went to truly independent operation.  Or maybe they were actually independent (see 40-55 seconds), and were flying in tight formation because I had the throttles balanced so good already???  

 

Anyway, the thing that concerns me is the final 35 seconds or so, when I let it idle.  If I'm understanding what I'm seeing, it looks like the steppers are closing off the bypass air to try to bring the idle RPM back down to 1150, and they're closing down a lot more than they used to (~50, instead of ~100 like they were before I started).  Am I in danger of encountering circumstances where the steppers can't close down enough to keep the idle speed down to 1150 RPM?  Say, on a particularly cold day with good air density?

 

 

 

[dirtrider]

13 minutes ago, Joe Frickin' Friday said:

 

I think what Larry meant was that water is useful for detecting much smaller changes in pressure than mercury.  You guys are on the same side.  

 

 

Got the right TB back on the bike on Tuesday, and checked things out yesterday.  The results are, um, interesting.  

 

On the plus side, the TwinMax says vacuum balance at idle (with steppers disabled) is miraculously perfect.  Better than it was before I started the whole project.  Whatever I did to the left side to make it let more air in, somehow I managed to also do to the right side. The bike idles and runs great.

 

On the minus (or may be just "huh, that's weird") side, the stepper motors don't behave like they used to.  This is the data from yesterday:

 

 

 

This was after a good warm-up ride, on a good warm day (upper 70s yesterday).  For this log, I didn't actually start the engine until about t=4 seconds, and you can see a couple of periods (20-40 seconds and 55-65 seconds) where I was twisting the grip a bit to try to warm up the O2 sensors faster.  Even so, sensor #1 never really went active, and the two stepper motors never went to truly independent operation.  Or maybe they were actually independent (see 40-55 seconds), and were flying in tight formation because I had the throttles balanced so good already???  

 

Anyway, the thing that concerns me is the final 35 seconds or so, when I let it idle.  If I'm understanding what I'm seeing, it looks like the steppers are closing off the bypass air to try to bring the idle RPM back down to 1150, and they're closing down a lot more than they used to (~50, instead of ~100 like they were before I started).  Am I in danger of encountering circumstances where the steppers can't close down enough to keep the idle speed down to 1150 RPM?  Say, on a particularly cold day with good air density?

 

Morning Mitch

 

Did you do a new TPS re-learn after L/H side reinstall? 

 

You will probably have the lowest commanded stepper situation after a  long freeway run in very hot weather as the engine oil & engine friction is probably lowest at that point.

 

Take it for a looooooong ride in hot weather then do a quick stepper position check.

 

Those hot steppers seem too close to be believable so they probably didn't go (or stay)  independent.  With the stepper count that even you need to put your twin max back on it to see  what the actual  vacuum delta is with even stepper pintle position. If it is good (or great) then just ride the motorcycle.

 

If you encounter higher engine idle than you think is normal  at any time in the future then you can always back your base idle screws out 1/4 (evenly side to side) as that will jack the hot curb idle stepper count up a little.   

 

 

 

[Joe Frickin' Friday]

14 minutes ago, dirtrider said:

Did you do a new TPS re-learn after L/H side reinstall? 

 

 

Battery disconnected for a minute or so with ignition key on, then connect the battery and (with key on) cycle throttle from min to max a few times?   (cuz that's what I did.)

 

14 minutes ago, dirtrider said:

You will probably have the lowest commanded stepper situation after a  long freeway run in very hot weather as the engine oil & engine friction is probably lowest at that point.

 

Take it for a looooooong ride in hot weather then do a quick stepper position check.

 

Sensible.  Will have to wait for warmer weather this summer and see what it does.  Freeway is a couple of miles from my house, so maybe I'll bring my laptop and GS-911 with me so I can stop at the park-and-ride lot at the off ramp and check it immediately after coming off of the highway.

 

I guess if the steppers aren't hitting zero under the hottest idling conditions, then I'm good to go?

[dirtrider]

9 minutes ago, Joe Frickin' Friday said:

 

I guess if the steppers aren't hitting zero under the hottest idling conditions, then I'm good to go?

Morning Mitch

 

That is pretty well the bottom line.

 

I'm not even sure if your BMS-KP can command a running engine  "0"  stepper count (except at engine pre-start to home the steppers)  as you never want to operate a stepper that far closed to prevent pintle seat wear.

 

Please post a follow up to your shaft install in a couple of months of riding as I am curious on how these shaft installs are progressing. (all that I have done so far seem to be working out good) 

 

 

[Joe Frickin' Friday]

6 minutes ago, dirtrider said:

Please post a follow up to your shaft install in a couple of months of riding as I am curious on how these shaft installs are progressing. (all that I have done so far seem to be working out good) 

 

 

Will do.  Thanks so much for all of your help on this!  Your drawing my attention to the problem in the first place has likely saved me from an expensive/inconvenient tow ride home, possibly from out of state, and your instruction on how to execute this fix (instead of buying two new TBs) has saved me a good $1250.  

 

 

[ed may]

Ed here, 06 RT.  Reporting back after my second ride since the replacement of both shafts with cams. The bike still runs great, even smoother than before the repair.   I put about 40 miles on it today,  (first ride after the repair was about 100 miles, a day or two after the repair, about 3-4 weeks ago).  Today, when I got back, I shut it off to pop the seat for access to the connector then started it right back up.   I set up the laptop, then took it around the block to make sure it was in closed loop, or whatever you want to call it (that comes from my auto tech days, basically means it's out of warm up/start up mode)  anywho, my stepper motors were bouncing around quite a bit, actually surprised me but I took several pictures of the values, snapped the throttle once or twice, and took some more pictures. They started out at 35 each, engine temp 118.5 C.   Engine temp up to 123.8 C, still 35/35.    As the bike sat idling, they began to change,   29/24  then 34/27, then 32/20 then I took it for a quick spin around the block, came back and took some more photos of the data, steppers were a little lower, I think the engine was getting warmer at this point so I set up fans.  The engine temp was a little higher at this point,  at 133.5 C  they were 29/17,  at 132.8 C they were 28/15, as it sat idling with fans on it, they got lower 25/11,  then engine at 133.5 C and steppers at 19/7, then 12/12, then 11/11, then 11/9, then I stopped taking pictures.  I did see them bottom out around 6 I think.  That's probably a little too low for my liking, as Dirtrider mentioned a possibility of the pintle seats wearing if they get much lower than that.  I am a little concerned that they will bottom out as the summer temps climb with an extended idle at a light.  I will monitor them after every ride and check back.  

If I wanted to get those numbers up a little, I would imagine a very slight adjustment of the idle stop screws would do it (backing them out the EXACT same amount to close the throttle plates more/ to force  the steppers to operate at higher numbers, BUT I am VERY hesitant to do that, but if the numbers get lower than 5, I think it would be wise to get them up a little, not sure how else to do it.  What do you think Dirtrider??  AH, just read your reply to Mitch about backing his stop screws out 1/4 turn if necessary, so I guess that would be my next move if they get any lower than 5 after a long run.  I'll have to get my spare key ready to pop the seat to get to the connector without shutting off the engine.  

[KDeline]

Well crap. Left me stranded.

[dirtrider]

1 minute ago, KDeline said:

Well crap. Left me stranded.

 

 

Evening KDeline

 

Yep, those little cracks turn into larger cracks then the plastic cams  fall off the lever without warning, plus you can only see/inspect the outside so the inside can be cracked  worse than the outside without notice. 

 

Are you going to repair it yourself?    If so then you came to the right thread.  

[KDeline]

I am tempted but it seems a bit higher then my pay grade. Not happy about spending $1700.00 plus for a 93,000 mile, 12 year old bike... Ugg.

 

[KDeline]

7 minutes ago, dirtrider said:

Evening KDeline

 

Yep, those little cracks turn into larger cracks then the plastic cams  fall off the lever without warning, plus you can only see/inspect the outside so the inside can be cracked  worse than the outside without notice. 

 

Are you going to repair it yourself?    If so then you came to the right thread.  

On a side note,  this bike has always run like the old oilheads did when surging. Or just a hint of a miss. I purchased with 32,000 miles, could this have contributed to that? I could never dial it out.

[Ponch]

22 minutes ago, KDeline said:

Well crap. Left me stranded.

Did the same to me in 2015. 

[dirtrider]

17 minutes ago, KDeline said:

On a side note,  this bike has always run like the old oilheads did when surging. Or just a hint of a miss. I purchased with 32,000 miles, could this have contributed to that? I could never dial it out.

Evening KDeline

 

No, I'm not totally sure what causes the failure but it seems that age & heat cycles seem to be a big contributor.

 

Just not a very good design as the plastic not only cracks, but due to the way the plastic is molded on once they crack the 3 pass through attachments to the lever  cause a camming effect to make them split off even easier. 

 

You do have the option to send your throttle bodies to Bing USA to have the cams or cams+shafts replaced but they don't do any measuring as they just take your money,  install the new parts, then pat you on the butt & send your TB's back.

 

There is also an aluminum cam deal that go on over you existing levers (once the old plastic is totally removed). You can do it yourself or send the TB's to the company & have them do it. Not cheap but a lot less $$$$  than new TB's. (you basically get what you get)

 

This should be a recall deal as it is dangerous but so far nothing is being done, probably not enough riders have reported it as the same type failure issue.