Throttle Body Pulley Repair

[dirtrider]

18 minutes ago, bruce2000ltc said:

I agree about those rings.  I'm thinking about getting a set from Bulgaria and cutting a horseshoe slot to clear the shaft with a thin cutoff wheel on my Dremel.  Even if I had to cut the ring in two pieces I think it would still work fine or am I missing something here?

Afternoon bruce2000ltc

 

I haven't ever installed those specific cams but just looking that pictures__

 

If the 3 screws all end up going through the throttle shaft lever & not right out to the edge then personally I would probably just toss that ring in the trash.   

 

I would just drill & tap the lever for the screw threads (be more robust threads) as the lever is about 2.45mm thick & that thin little ring is only 1.38 mm thick (according to the pictures above). 

 

Then I would install 3 little locking nuts on the backside of the lever using Lock-tite to retain the nuts. 

 

If that throttle shaft lever is strong enough to take the throttle cable pull & abuse with just a plastic POM cam) then it surely should with a thicker alloy cam bolted on.  

 

With the 3 screws threaded directly into the lever & using tapered flathead screws there is no way the cam position could move due to any slight play in the screw holes. 

 

This working as I stated above I can't say for sure until the alloy cams are held in PROPER place then 3 screw holes crisply marked to show their position on the shaft lever.   

 

If the screws go through the notches & the large hole then you would need to use the ring & in that case I probably wouldn't cut a gate in it as that could allow the ring to eventually open up & allow cam migration.

 

If I did cut a gate in the lock ring then I would probably use Lock-tite 609 between the lock ring & the back side of the lever (under constant compression Lock-tite 609 is a powerful adhesive)   

[Ponch]

We generally have 5 choices here:

1. Buy new throttle bodies. 

2. Buy used throttle bodies

3. Buy new pulleys with shafts from the Bing Agency

4. Buy the pulleys from Beemer Bits

5. Buy these Bulgarian pulleys. 

 

I chose #2 as at the time of breakage the only other option was #1. #3 and #5 require dissembling the throttle bodies with a procedure outlined in great detail by Dirtrider. #4 doesn't require disassembly, but costs more than #3 and #5. What isn't factored in, at least it seems, is the time it takes to disassemble and reassemble correctly and the entropy of problems the average bear might encounter. If I was going to go though the disassemble route, I'd go with Bing. It's OEM and I'd rather support a local company, otherwise with the time consideration, I might bite the bullet and get the beemer bits pulleys, although dirtrider has a good point about them RE they're not anodized. If you want to cut the ring to save time, you're modifying a one off design and YMMV. More entropy into the equation. My advice, unsolicited as it is, would be to choose which repair offers the highest quality and reliability and put cost second or third, all things being equal(within a certain price range, in this case under $500). In that case, it's probably the Bing pulleys, and by that I mean buying the pulleys on shafts from Bing and installing them yourself.

[SHIMHEAD]

    For what it's worth, here is the link to the Facebook page for the cams. There is a bit more detail about the material used and the coating applied. As before, comments welcomed.

https://m.facebook.com/story.php?story_fbid=175706568803975&id=100090938976784&mibextid=CDWPTG

 

   Or, search "Aluminum Throttle Cam" (ATC) on Facebook.

[KetoSoi]

On 6/19/2023 at 1:07 PM, bruce2000ltc said:

I agree about those rings.  I'm thinking about getting a set from Bulgaria and cutting a horseshoe slot to clear the shaft with a thin cutoff wheel on my Dremel.  Even if I had to cut the ring in two pieces I think it would still work fine or am I missing something here?

I was looking at that install video again, seems like plenty of meat on those rings. Just cutting out a slot for the shaft should suffice, the diameter of the shaft was notably smaller than the hole in the ring. The ring should still have the structural rigidity it needed, splitting it in 2 though, would introduce a different dynamic, I don't see any need/advantage to do such thing. There is no lateral movement of the pulley, and as I mentioned before, it is also keyed to the end of the shaft, the cable/pulley action is entirely longitudinal relative to the ring. With sufficient red locktite in the places the manufacturer indicated, shouldn't be a need to do anything else. The amount of variance longitudinally should be minimal since they are keyed, nothing a TB sync shouldn't take care of.

 

That's my read on it at least, YMMV ;) Its an experiment based on observable characteristics, so unless you discover some caveat not notable in the video/pics, et all, it seems a good course to proceed on.

 

K

 

[bruce2000ltc]

I ordered the aluminum throttle cams from Bulgaria yesterday.  I'll report back after I complete the repair.  I wanted to replace the left cam chain tensioner at the same time since the throttle body needs to be out of the way but they are out of stock at Euro MotoElectrics.  My '13 RT w/73k has had the occasional rattle at startup for awhile.

[Gary Kubel]

Hi all, my first post here, greetings from the Gold Coast Australia. I replaced the plastic pulleys with new plastic ones from bing. The CNC ones are clearly the best fix but had to keep the costs down.

I did this without removing the shafts. All I did was shave the peened shaft end flat using a flapper wheel (less aggressive than a grinder) and prised the old pulleys off. Fitting the new ones needed just a light tap using a small socket as a drift to house them. (Keep it light or the butterfly may be damaged.) I drilled the shafts with a 3.5mm drill then tapped to suit a 4mm bolt. I decided that a stud and nut would be best so with the nut on the bolt and a suitable washer screwed the bolts home, tightened the nut down and then cut off the excess. I also used loctite on the bolt and nut. Note that you need to have all the cable mounting plastics fitted as there is not enough room to get the large head screws in once the pulley is fitted. All up the job took about 30 minutes. 
PS- I removed the throttle bodies without removing the air box. They will prize out by pulling out from the air box side first. Give it all a spray of WD40 and it will all slip out.  The original metal hose clamps will need to be cut off and replaced with new 70mm hose clamps. Replacement is the reverse, put the cylinder side in first then with lots of WD40 carefully guide the airbox side in using a plastic tool, not a screwdriver or you may cause a split. All good as new again. Here are some pics…

[dirtrider]

8 hours ago, Gary Kubel said:

Hi all, my first post here, greetings from the Gold Coast Australia. I replaced the plastic pulleys with new plastic ones from bing. The CNC ones are clearly the best fix but had to keep the costs down.

I did this without removing the shafts. All I did was shave the peened shaft end flat using a flapper wheel (less aggressive than a grinder) and prised the old pulleys off. Fitting the new ones needed just a light tap using a small socket as a drift to house them. (Keep it light or the butterfly may be damaged.) I drilled the shafts with a 3.5mm drill then tapped to suit a 4mm bolt. I decided that a stud and nut would be best so with the nut on the bolt and a suitable washer screwed the bolts home, tightened the nut down and then cut off the excess. I also used loctite on the bolt and nut. Note that you need to have all the cable mounting plastics fitted as there is not enough room to get the large head screws in once the pulley is fitted. All up the job took about 30 minutes. 
PS- I removed the throttle bodies without removing the air box. They will prize out by pulling out from the air box side first. Give it all a spray of WD40 and it will all slip out.  The original metal hose clamps will need to be cut off and replaced with new 70mm hose clamps. Replacement is the reverse, put the cylinder side in first then with lots of WD40 carefully guide the airbox side in using a plastic tool, not a screwdriver or you may cause a split. All good as new again. Here are some pics…

Morning  Gary Kubel

 

Does the throttle return spring clear that stud at wide open throttle? If it clears it must be real close to contacting. If those springs contact the stud it will eventually fail the return springs.  

[Ponch]

Also, a low profile oetiker clamp pliers will negate have to cut off the "hose clamps".  What's the deal with the one end of the spring hanging out?

[dirtrider]

18 minutes ago, Ponch said:

 What's the deal with the one end of the spring hanging out?

Morning Ponch

 

That curved spring tail hooks around the plastic bracket. Bracket is not reinstalled yet in picture above. 

 

[Ponch]

15 minutes ago, dirtrider said:

Morning Ponch

 

That curved spring tail hooks around the plastic bracket. Bracket is not reinstalled yet in picture above. 

 

Yeah, he doesn't have the bracket installed. I thought it looked off. 

[dirtrider]

22 minutes ago, Ponch said:

Yeah, he doesn't have the bracket installed. I thought it looked off. 

Afternoon Ponch

 

Yes, you don't see many pictures with that cable bracket removed as it doesn't have to be removed even when installing new cams or new cams with shafts. In fact it is held on with tamper-proof screws so it doesn't get easily removed. 

[IVAN_Ivanov]

Hope those detailed picture helps!

 

[bruce2000ltc]

I installed the aluminum cams that are shown in the post above this one.  My plan was to cut a horseshoe slot in the ring that holds the cam in place and slide it over the shaft between the shaft plate and the throttle body.  None of my four drill press vises opened wide enough to hold the throttle body and I just didn't feel comfortable putting the throttle body in my bench vise and drilling the shaft by hand so I removed the cams with the shafts.  Everything was pretty straight forward after that.  Even with the plastic cams cracked it took a lot of effort to remove them.  My guess is they would of lasted a long time.  The aluminum cams are a press fit onto the shaft plate.  You have to mark and drill the shaft plate for the screws to pass through and engage the ring with the three threaded holes.  Once screwed in place with locktite the aluminum cam is not going anywhere.  I put everything back together, reinstalled the throttle bodies and did a carb sync per the GS-911.  I've ridden a little over 100 mile and the bike runs great.  It's nice to use WOT without fear of breaking a throttle cam!

Special thanks to "dirtrider" for his detailed writeup on how to measure and remove/replace the throttle plates and shafts.  And, thanks to everyone else who posted comments and photos on this procedure--you are all a great resource.

[pwillikers]

Vehicle: 2011 R1200RT (Model: K26, 0440)

 

The throttle bodies on my Camhead were cracked.  I'm appending here in the Hexhead section due to this extensive thread.

 

I inspected and discovered an epoxy repair so I ordered the Bulgarian replacement cams from ebay and installed them.  This thread and Dirt Rider's separate thread were of tremendous help in tackling this project.  Big thanks!  (I also documented my repair in the Camhead section with links to this and Dirt Rider's relevant thread here in the Hexhead section.)

 

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

 

1. Get the pliers designed to install/remove the earless band clamps that hold the throttle bodies in place.   I had not seen these specific clamps before and the proper pliers made removing and reinstalling them a cinch.  Aliexpress $12.

 

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

 

AND another data point for Dirt Rider:  I removed and measured both TBs prior to disassembly. With the throttle plates shimmed top and bottom with .0015" feeler gauges and the throttle plate seated with slight pressure assisting the return springs per your recommendation, the throttle stop gap was .008" on both sides - seemingly in perfect synchronicity.  Upon reassembly, the pre-disassembly gap of .008" was achieved without adjustment.

 

 

[Ponch]

32 minutes ago, pwillikers said:

Vehicle: 2011 R1200RT (Model: K26, 0440)

 

The throttle bodies on my Camhead were cracked.  I'm appending here in the Hexhead section due to this extensive thread.

 

I inspected and discovered an epoxy repair so ordered the Bulgarian replacement cams from ebay and installed them.  This thread and Dirt Rider's separate thread were of tremendous help in tackling this project.  Big thanks!

 

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

 

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

 

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

 

 

 

 

 

I got pliers like these: https://www.amazon.com/TJ-Longda-Oetikers-Profile-Product/dp/B00GA8X2OC

 

My pulleys broke off the shafts, so it was easy to get the cables off. 

[Ponch]

The guy that makes the pulley replacements contacted me about doing a video about them. If I get them I will replace the pulleys on the original throttle bodies as I saved them. When mine broke there were no solutions other than new or used throttle bodies. 

[IVAN_Ivanov]

Nice!
https://www.etsy.com/shop/ATCam?ref=seller-platform-mcnav

[6speedTi]

Found another manufacturer of aftermarket pullies for our boxer engines. I just wanted to add another link. Made in Italy 🇮🇹 

 

https://www.ebay.com/itm/175078812578?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Qwld0fyzSt6&sssrc=4429486&ssuid=IRPCbWKTR-W&var=&widget_ver=artemis&media=COPY

[Dave P]

I've got an 07 1200RT, have never inspected the pulleys on my TBs. 40k miles, seems to run fine, idles fine. if my pulleys are cracked, what kind of symptoms would I see? I had a friend hook up his 911 about a year ago and no codes came up. Dave

[6speedTi]

3 hours ago, Dave P said:

I've got an 07 1200RT, have never inspected the pulleys on my TBs. 40k miles, seems to run fine, idles fine. if my pulleys are cracked, what kind of symptoms would I see? I had a friend hook up his 911 about a year ago and no codes came up. Dave

No symptoms until total failure. When they totally break off from the cracks that cylinder drops to idle speed. If in doubt,  check them out before you find yourself on the side of the road some day. 

[chrisolson]

15 hours ago, Dave P said:

if my pulleys are cracked, what kind of symptoms would I see?

 

Its a physical crack in the pulley, not an electrical or software issue ... look at the first post in this topic for photo examples

[Dave P]

Got it- one of those Go / No Go kinda deals. I'll give it a look sometime soon. 
 

Plastic are great in many applications, but I often wonder why small critical components (especially near engine heat) are molded in plastic. D

[Hosstage]

Just now, Dave P said:

Plastic are great in many applications, but I often wonder why small critical components (especially near engine heat) are molded in plastic. D

All decisions are economic.

[dirtrider]

6 minutes ago, Dave P said:

Got it- one of those Go / No Go kinda deals. I'll give it a look sometime soon. 
 

Plastic are great in many applications, but I often wonder why small critical components (especially near engine heat) are molded in plastic. D

Afternoon Dave

 

A number of reasons, from cost per piece, to being able to easily mold complex shapes, to less cable wear than steel cams, to less wear to the cable track in alloy cams, to easy attachment to the throttle shaft levers, etc.

 

Nothing wrong with plastic throttle cams as a number of motorcycle & auto companies use plastic & have used plastic for years now.  It works, and works good, if done CORRECTLY. 

 

With the proper material attached in a way that doesn't put a wedging force on the plastic cam like the BMW boxer design does then plastic cams can live a long trouble free life just fine   

 

The BMW problem isn't all a plastic cam problem it is also a design problem. In my eyes it was a designed-to-fail thing right from the beginning. 

 

 

 

  

 

 

[Shane J.]

On 1/4/2024 at 2:00 PM, 6speedTi said:

Found another manufacturer of aftermarket pullies for our boxer engines. I just wanted to add another link. Made in Italy 🇮🇹 

 

https://www.ebay.com/itm/175078812578?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Qwld0fyzSt6&sssrc=4429486&ssuid=IRPCbWKTR-W&var=&widget_ver=artemis&media=COPY

This looks like a simpler install for only a little more dollars. Has anyone used this kit yet?

[dmsantam]

Good afternoon all, I used this kit on my hexhead 2005 GS about 12,000km ago and it's had no issues. My plastic pulleys hadn't broken but were cracked and I didn't want to get stranded. 

 

https://www.munichmotorcycles.com.au/product/test/

 

Note that it's Australian dollars, so about $220USD. 

 

You do have to remove the throttle shafts to fit it, and there are good pictures at the link, and a pdf which I've also attached. The cams are a press fit. 

PDF-Throttle-Body-Cam-Fitting.pdf

[aggieengineer]

Seems as if correcting BMW's engineering mistakes has become quite the cottage industry.

[Hosstage]

2 minutes ago, aggieengineer said:

Seems as if correcting BMW's engineering mistakes has become quite the cottage industry.

Come on over to the Harley side if you want to see engineering mistakes being corrected by the aftermarket. Talk about a cottage industry. That doesn't even speak to the huge performance industry for HDs.

[dirtrider]

15 hours ago, dmsantam said:

Good afternoon all, I used this kit on my hexhead 2005 GS about 12,000km ago and it's had no issues. My plastic pulleys hadn't broken but were cracked and I didn't want to get stranded. 

 

https://www.munichmotorcycles.com.au/product/test/

 

Note that it's Australian dollars, so about $220USD. 

 

You do have to remove the throttle shafts to fit it, and there are good pictures at the link, and a pdf which I've also attached. The cams are a press fit. 

 

Morning  dmsantam

 

Are those cams hard anodized? They don't look to be in the pictures but difficult to tell from the pictures. 

 

 

[dmsantam]

7 hours ago, dirtrider said:

Morning  dmsantam

 

Are those cams hard anodized? They don't look to be in the pictures but difficult to tell from the pictures. 

 

 

hi dirtrider, I don't believe they are anodized. 

 

cheers,

[Joe Frickin' Friday]

On 1/4/2024 at 7:19 PM, Dave P said:

I've got an 07 1200RT, have never inspected the pulleys on my TBs. 40k miles, seems to run fine, idles fine. if my pulleys are cracked, what kind of symptoms would I see? I had a friend hook up his 911 about a year ago and no codes came up. Dave

 

 You're gonna want to inspect those.  I had an '09 with about 50K miles, and a couple of years ago discovered cracks in the plastic cams.  As noted by others, you don't experience any performance symptoms at all until parts of the plastic cam completely crack away from the steel hub/spindle...at which point the bike becomes unrideable and leaves you stranded by the side of the road.

[9Mary7]

In case anyone doesn't feel confident in doing this repair themselves, there is an independent shop in the Phoenix area that does them. Even by mail if you are geographically challenged.

No connection to me, a buddy of mine uses them for his bikes.

Motoghost.com

[Dave P]

I like to think of myself as pretty capable but messing with the throttle bodies has always made me kinda nervous . Depending on what I see on my 07 with 40k I might send out for repairs.Thanks for that lead. D

[Shane J.]

I went ahead and bought this version replacement cams. https://www.ebay.com/itm/175078812578?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Qwld0fyzSt6&sssrc=4429486&ssuid=IRPCbWKTR-W&var=&widget_ver=artemis&media=COPY

It was more expensive than the Bulgarian version, but required no drilling, only had to tap the existing hole on the throttle shaft mount with threads for the included screw. I did not have the locktite #638 and none was available locally, so I used loctite 263 red. I also used gel superglue between the cam and the mounting surface. It's not going anywhere. The old plastic cams were cracked and I was able to remove them just by twisting with my hands and a little cleanup with pliers. All in all the job was much easier than I expected and now I have one less thing to worry about on a long ride.

 

[KetoSoi]

23 hours ago, Shane J. said:

I went ahead and bought this version replacement cams.........

So after doing it, do you think they could be installed without removing the shafts from the TB?

 

 

K

[9Mary7]

I read their instructions (on Ebay) and no, you cannot install the required spacer behind the flange without removing the shafts. 

[Shane J.]

You have to remove the shafts. But really, that whole process was way easier than I expected and went very smoothly. All the links in this topic to others doing similar installs are very helpful.