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aggieengineer

Throttle Body Pulley Repair

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aggieengineer

After reading about the failures some other riders had experienced, I decided to have a look while the plastic was off for some routine maintenance. I really didn't expect to find anything wrong. 

Wrong!

 

This is the left side:

Left.thumb.JPG.58b5600e09e2a7c042902ff2ca9ebf27.JPG

 

 

This is the right side. Note that there are actually three cracks in this one - 9:00, 3:00, and at the 7:30 position. 

Right.thumb.JPG.597d42fd9cbd4831122f8be6ab106643.JPG

 

I think this is a matter of age and heat causing the plastic to shrink and become brittle. I don't ever twist the throttle to the stop while riding, and don't believe this is self-induced. The third smaller crack is evidence of that. Throttle cable tension does not put significant stress on  that location.

The bike is 11 years old, but with only 42,000 careful miles. 

 

Here are the options:

 

1. Send it to the Bing Agency for repair with the same part. I called their Technical Service number, and had a very informative chat. Replacement of both pulleys is $312, but long-term I can expect the problem to recur. 

2. Replace the pulleys with metal ones from Beemer Bits for a somewhat shocking $450....plus shipping! 

 

I'm inclined at this point to go with the metal parts and just be done with it. Has anyone installed them yet? I'd love to hear what the process was like. 

 

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dirtrider
2 hours ago, aggieengineer said:

Here are the options:

 

1. Send it to the Bing Agency for repair with the same part. I called their Technical Service number, and had a very informative chat. Replacement of both pulleys is $312, but long-term I can expect the problem to recur. 

2. Replace the pulleys with metal ones from Beemer Bits for a somewhat shocking $450....plus shipping! 

 

I'm inclined at this point to go with the metal parts and just be done with it. Has anyone installed them yet? I'd love to hear what the process was like. 

 

 

 

Evening Aggieengineer

 

Personally I haven't done the alloy ones but I do know a rider in my area that did his own with no issues & he isn't all that mechanically inclined.

 

Beemer Bit has (had anyhow)  detailed install instruction on their web site. I haven't looked lately but  last that I looked it looked pretty simple. (the good part is that the difficult to re-set-correctly idle stops are on the remaining arm so that should make it easier as setting the base air-flow (base idle stop screws) is the difficult part to get set back to correct.

 

I have installed a couple of sets of the Bing OEM shafts/cams & those are not hard to install but a bit fiddly to get the  base idle screws back close to correct.

 

The Bing shafts/cams (parts only) are a LOT cheaper than having them do it, or buying  the Beemer Bits parts, or having them do the repair.

 

With the Bing parts-only method  you need to do some preliminary balance checks & record those then do 'ONLY' one side at a time using the existing factory Throttle Body as a known.

 

Bing parts only______         http://bingcarburetor.com/store/p134/Type_77_Throttle_Body_Pulley_%26_Shaft_Assembly.html

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lkraus

Bing sells the parts if you want to DIY.  Pulleys on shafts for ~$100/ pair. Should be good for another 8-10 years. Or Pulleys only for ~$40, but reportedly tricky to mount on the shafts.  Or go full shade-tree mechanic and reinforce what you have with a big washer and JB Weld.

 

Looks like I need to find a touch-typing class....

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Ponch

Mine broke after 5 years. I just found a set of throttle bodies on ebay. There wasn't a repair then from bing or Beemer bits. The only other option was new throttle bodies. I made a complaint to the NHTSA or whatever government agency it was. There were others for the same thing. BMW kind of conformed to Eilenberger's Axiom (Which was related to the fuel strip):

1. What problem?

2. Oh, that problem. First we've heard of it.

3. You caused it

4. Your environment caused it (fuel properties usually)

5. We have no problem

 

It soured me on BMW for awhile. I've since learned their cars use a lot of crappy plastic on engine pieces that crumble with time. I just find it lunacy that they would build it like that. 

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Shane J.
19 hours ago, lkraus said:

Bing sells the parts if you want to DIY.  Pulleys on shafts for ~$100/ pair. Should be good for another 8-10 years. Or Pulleys only for ~$40, but reportedly tricky to mount on the shafts.  Or go full shade-tree mechanic and reinforce what you have with a big washer and JB Weld.

 

Looks like I need to find a touch-typing class....

So the big washer is the reinforcement and the JB Weld to hold it to the plastic cam? Sounds like a good preventative measure even if they are not cracked yet. Reasonable assumption?

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dirtrider
20 minutes ago, Shane J. said:

So the big washer is the reinforcement and the JB Weld to hold it to the plastic cam? Sounds like a good preventative measure even if they are not cracked yet. Reasonable assumption?

 

 

Afternoon   Shane J.

 

I'm not sure about that one as without peripheral support I doubt that a washer & JB would prevent that plastic hub from  cracking  but it would cover any cracking up so you couldn't see it with an inspection.   

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Ponch
8 hours ago, dirtrider said:

 

 

Afternoon   Shane J.

 

I'm not sure about that one as without peripheral support I doubt that a washer & JB would prevent that plastic hub from  cracking  but it would cover any cracking up so you couldn't see it with an inspection.   

I was going to mail my old ones back to BMW with a big FU on a note inside, but then I thought better of it as they'd probably have me arrested for terrorism.  It's beyond JB Weld though. It's bad engineering and poor execution. The right repair is the metal one, at least with what we know now. 

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aggieengineer

I agree. A set of aluminum replacements is on the way. I'll post some additional information on the install. Surely I'm not the last person who will have to deal with this. 

Fate being what it is, however, I suspect a recall will be issued about fifteen minutes after I finish the project. 

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Ponch
1 hour ago, aggieengineer said:

I agree. A set of aluminum replacements is on the way. I'll post some additional information on the install. Surely I'm not the last person who will have to deal with this. 

Fate being what it is, however, I suspect a recall will be issued about fifteen minutes after I finish the project. 

 

And if there's a recall, what recourse do I have? Unless I had a dealer fix it, none I imagine. Seems more and more people are having this happen too. I was an early adopter. 

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dirtrider
18 minutes ago, Ponch said:

 

And if there's a recall, what recourse do I have? Unless I had a dealer fix it, none I imagine. Seems more and more people are having this happen too. I was an early adopter. 

 

Morning Ponch

 

You do (might)  have some recourse (if like the fuel pump pass through recall) as BMW had a special policy to reimburse riders for some of the cost encountered from non-BMW repair if receipts were shown (obviously it didn't reimburse for the entire amount).  

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Ponch
3 minutes ago, dirtrider said:

 

Morning Ponch

 

You do (might)  have some recourse (if like the fuel pump pass through recall) as BMW had a special policy to reimburse riders for some of the cost encountered from non-BMW repair if receipts were shown (obviously it didn't reimburse for the entire amount).  

I guess that remains to be seen. I have my doubts they'd ever address it, but riders that have this problem need to put in a complaint to the feds. 

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aggieengineer

Well, it's done, to a point. The original plastic pulleys came off easily. The plastic was fairly brittle. I used a pair of small sidecutters for the job.

 

P1040118.JPG.1116852b9dbbb2190ab24054afee83c0.JPG

 

 

I did encounter one problem. On the right unit, there was not adequate clearance between the throttle arm and the throttle body casting. The new aluminum pulley was binding. It is only two-thousandths thicker in that area than the plastic part. 

The technician from Beemer Bits said that they sometimes have to file away a bit of the body casting for clearance. There was about ten-thousandths axial play in the shaft, so I took a chance and loosened the butterfly screws and slid the shaft out a bit. Collective cringe...I know. I was as careful as I could be to maintain the gap between the butterfly and the throat accurately, and identical under bright light to the left (unmolested) unit. There seems to be a bit of manufacturing slop in this throttle. 

P1040127.JPG.f74eaca889a2a325ed90982da5ab81dc.JPG

 

After that, it went together smoothly. Fit was very nice. The left side went on without any problem. 

P1040130.thumb.JPG.75969ee0057c1258bb32459bcec2dcef.JPG

 

Now for the scary part. I reinstalled the units, hooked up the GS-911 and vacuum balancer for a test. 

Idle was the same as before, and throttle balance was unchanged. I expected some problem, but so far nothing.

 

I'm going to try to attach some data logs for anyone interested. Here goes.

Log b.pdf

 

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dirtrider
3 hours ago, aggieengineer said:

Well, it's done, to a point. The original plastic pulleys came off easily. The plastic was fairly brittle. I used a pair of small sidecutters for the job.

 

 

 

 

I did encounter one problem. On the right unit, there was not adequate clearance between the throttle arm and the throttle body casting. The new aluminum pulley was binding. It is only two-thousandths thicker in that area than the plastic part. 

The technician from Beemer Bits said that they sometimes have to file away a bit of the body casting for clearance. There was about ten-thousandths axial play in the shaft, so I took a chance and loosened the butterfly screws and slid the shaft out a bit. Collective cringe...I know. I was as careful as I could be to maintain the gap between the butterfly and the throat accurately, and identical under bright light to the left (unmolested) unit. There seems to be a bit of manufacturing slop in this throttle. 

 

 

After that, it went together smoothly. Fit was very nice. The left side went on without any problem. 

 

 

Now for the scary part. I reinstalled the units, hooked up the GS-911 and vacuum balancer for a test. 

Idle was the same as before, and throttle balance was unchanged. I expected some problem, but so far nothing.

 

I'm going to try to attach some data logs for anyone interested. Here goes.

 

 

 

Afternoon aggieengineer

 

The numbers that you posted look good but they might change after the adaptives re-lean as you ride it & it goes through a couple of  ignition cycles.

 

If your hot engine TB balance stays within reason  with locked steppers after a few rides & the hot  engine idle  stepper count stays close with unlocked steppers then you are golden.    

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aggieengineer

Hopefully I dodged a bullet on this one. I stuck a seat on it and took it for a short ride to see if I could induce any misbehavior, for example rapid drop to idle from cruise. Seems fine so far. 

I'm busy helping my son with car shopping this afternoon, then have a 3-day airline trip, so the full test will happen next week. 

I have to say that it is very reassuring to have some expert help to smooth the way. Thanks indeed!

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aggieengineer

Before I forget about this, there was one piece of the original pulleys that required some effort to extract since it was molded onto the throttle arm.

 

P1040119.JPG.0fb3c8ab397a08013ef92edc0d049dbb.JPG

 

I carefully ran a drill bit (#21 I think) through the hole to remove the plastic in the hole in the throttle arm, and that released the flat piece which had remained on the backside.

 

Also, I didn't use the blue Loctite 242 which was supplied, instead substituting Permatex 64000 sleeve retainer. Not likely to make a difference, but I'm hopelessly conservative. 

 

Standing by for the recall......

 

 

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Ponch
24 minutes ago, aggieengineer said:

Before I forget about this, there was one piece of the original pulleys that required some effort to extract since it was molded onto the throttle arm.

 

P1040119.JPG.0fb3c8ab397a08013ef92edc0d049dbb.JPG

 

I carefully ran a drill bit (#21 I think) through the hole to remove the plastic in the hole in the throttle arm, and that released the flat piece which had remained on the backside.

 

Also, I didn't use the blue Loctite 242 which was supplied, instead substituting Permatex 64000 sleeve retainer. Not likely to make a difference, but I'm hopelessly conservative. 

 

Standing by for the recall......

 

 

 

Put in a complaint with the feds. I did. The more people do, the more likely there will be a recall. 

 

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Mark C

Have cracked another one and think it is a real recall type problem, All this could be avoided with metal pulleys like old days. 

 New improved is actually backwards bullshito. 

 Drilled and safety wired with expoxy and flat washer to re-use.

Wondering how to LIMIT cable pull from going to end of throttle stop? I myself don't ever really use 100 % throttle pull and would give up a slight amount to never have this problem again, especially on the road when you snap it while passing cars on a back road!

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dirtrider
37 minutes ago, Mark C said:

Have cracked another one and think it is a real recall type problem, All this could be avoided with metal pulleys like old days. 

 New improved is actually backwards bullshito. 

 Drilled and safety wired with expoxy and flat washer to re-use.

Wondering how to LIMIT cable pull from going to end of throttle stop? I myself don't ever really use 100 % throttle pull and would give up a slight amount to never have this problem again, especially on the road when you snap it while passing cars on a back road!

 

Morning Mark

 

The problem is BMW is just about out of the woods so to speak on any Hexhead recall liability. There are exceptions & outliers but for the most part  "there is a limit on how far back a manufacturer has to go to fix problems without charging the owner. Vehicles eligible for no-cost repair can't be more than 10 years old as of the date the defect was determined".

 

I'm not sure what date is used as far as 'date the defect was determined' but that would probably be when a NATSA safety investigation was officially started, or maybe not until it is  officially  concluded.

 

If this problem would have been reported on a soccer mom's mini van, or a senators nephew's motorcycle then it would probably have been addressed already. But seeing as it is happening on a 'perceived'  dangerous motorcycle then it doesn't put up much of a red flag until a number of fatalities or injuries can be tracked directly back to the problem. 

 

Plus, unless ALL the failures are reported to NATSA under the exact same heading & subheading with about the same failure wording then NATSA doesn't seem to be able to  put 2+2 together & start an investigation.

 

Get it on the national news with a death or couple of injuries THEN it will get addressed.

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Ponch
35 minutes ago, dirtrider said:

 

Morning Mark

 

The problem is BMW is just about out of the woods so to speak on any Hexhead recall liability. There are exceptions & outliers but for the most part  "there is a limit on how far back a manufacturer has to go to fix problems without charging the owner. Vehicles eligible for no-cost repair can't be more than 10 years old as of the date the defect was determined".

 

I'm not sure what date is used as far as 'date the defect was determined' but that would probably be when a NATSA safety investigation was officially started, or maybe not until it is  officially  concluded.

 

If this problem would have been reported on a soccer mom's mini van, or a senators nephew's motorcycle then it would probably have been addressed already. But seeing as it is happening on a 'perceived'  dangerous motorcycle then it doesn't put up much of a red flag until a number of fatalities or injuries can be tracked directly back to the problem. 

 

Plus, unless ALL the failures are reported to NATSA under the exact same heading & subheading with about the same failure wording then NATSA doesn't seem to be able to  put 2+2 together & start an investigation.

 

Get it on the national news with a death or couple of injuries THEN it will get addressed.

 

the more people put in complaints, the more likely they'll do something. I have a feeling people just fix it and move on, not holding BMW responsible for shoddy engineering and manufacture. If the NHTSA can't figure it out, what prompted the fuel strip recall? I think this is more serious. I know on the car side, BMW has lousy plastics on engine parts that fail where metal parts wouldn't have. Got to wonder what crack they're smoking. 

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dirtrider
16 minutes ago, Ponch said:

 

the more people put in complaints, the more likely they'll do something. I have a feeling people just fix it and move on, not holding BMW responsible for shoddy engineering and manufacture. If the NHTSA can't figure it out, what prompted the fuel strip recall? I think this is more serious. I know on the car side, BMW has lousy plastics on engine parts that fail where metal parts wouldn't have. Got to wonder what crack they're smoking. 

 

Morning Ponch

 

I don't believe there was a fuel strip recall, it was more of an offered extended warranty on failed strips not a real (return all vehicles) type recall.

 

My guess is that BMW did the extended warranty in  an effort to prevent further investigation & prevent a forced recall.  

 

The problem for BMW with a forced recall would have been that they would have needed to come up with a real (verified) lasting fix. THAT would have been W-A-Y more expensive than just replacing fuel strips on the ones that failed.

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Ponch
29 minutes ago, dirtrider said:

 

Morning Ponch

 

I don't believe there was a fuel strip recall, it was more of an offered extended warranty on failed strips not a real (return all vehicles) type recall.

 

My guess is that BMW did the extended warranty in  an effort to prevent further investigation & prevent a forced recall.  

 

The problem for BMW with a forced recall would have been that they would have needed to come up with a real (verified) lasting fix. THAT would have been W-A-Y more expensive than just replacing fuel strips on the ones that failed.

 

Well, ultimately, it's on them and I'll give them credit for waking me into reality about their products. To me, considering the cost/niche of their machines, this kind of stuff is totally unnecessary and ridiculous. 

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large-stache

Nice writeup and pics.  I just did mine yesterday.  I ordered the aluminum cams as a preemptive measure for an upcoming trip.  When I removed the throttle bodies, both were cracked, and the right one broke off when I slightly pushed on it with my thumb.  I hate to think it could've failed on my next ride. :( Expensive yes, but the peace of mind is worth it.

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Ponch
19 minutes ago, large-stache said:

Nice writeup and pics.  I just did mine yesterday.  I ordered the aluminum cams as a preemptive measure for an upcoming trip.  When I removed the throttle bodies, both were cracked, and the right one broke off when I slightly pushed on it with my thumb.  I hate to think it could've failed on my next ride. :( Expensive yes, but the peace of mind is worth it.

File it with the gov. 

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