BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

I just wanted to pass along some information for those interested in what's invloved in rebuilding the RH TB.

The bike: 2004 R1150R with 60k miles.

I ordered the parts from Bing, which cost around $90. The kit included all of the seals and a new throttle shaft.

Rebuilding the TB was very easy: 1) Remove the TB; 2) replace several (4) seals as well as the butterfly shaft. Clean TB with your favorite TB cleaner. The entire rebuild took about 30 minutes. The only special tool you need is a small snap ring plier; 3) reinstall and sync the TB's.

There was very little to no wear on the throttle shaft. Which is good considering I've read other posts that have seen excessive wear on the throttle shaft.

ProductUser

thats a fair amount of work.

any special reason to undertake such action?

what were the results?

I was hunting down a ticking sound that may have been coming from a worn throttle body shaft. Plus, it's been almost two decades since I rebuilt a TB or carb, so why not.

It really was easy and certainly well within the grasp of your average wrench.

ProductUser

Did it make any noticeable difference in the performance? Was it worth it?

R4R&R wrote:Did it make any noticeable difference in the performance? Was it worth it?

It did not make a bit of differance in performance. Cleaning the TB may improve fuel economy slightly, but that's about it.

It was worth it, in a personal way. I would walk away knowing that your TB shafts are not going to fail you for a very long time.

I have a lot of free time and I enjoy wrenching when I can; it's a complete divergence from the daily grind.

ProductUser

I am surprised how expensive that shaft kit was- for the R1100 they only charged me about $40. That ticking is usually caused by a throttle cable that's out of adjustment.

The sound comes from the tab on the throttle tapping against the stop screw. Put your finger on it next time you hear it- it most likely will go away.

The shafts do wear, and BMW will only sell you a $300 throttle body assembly. A can of carb cleaner is a great way to track down that problem. Just spray it around the throttle shaft while the bike is idling and see if the RPM changes. Any variation at all means air is leaking in!

Product User

I see that you are pretty much like me, get an idea and run with it.......

But hopefully, you can clear a burning question. Did you mike the old and new shafts in the area of the seals. It would be nice to be able to correlate the shaft wear over 60K miles of use. I would not have expected significant wear, unless there was a side to side alignment issue on the shaft.

If you didn't, maybe you can still do it on the old shaft, between the seal area and away from the seal area.......how about a pic of the seal area on the old shaft.......

boxermania wrote:Product User

But hopefully, you can clear a burning question. Did you mike the old and new shafts in the area of the seals. It would be nice to be able to correlate the shaft wear over 60K miles of use. I would not have expected significant wear, unless there was a side to side alignment issue on the shaft.

If you didn't, maybe you can still do it on the old shaft, between the seal area and away from the seal area.......how about a pic of the seal area on the old shaft.......

I didn't take any measurements between the shafts, nor do I have a micrometer. Well, I guess I could go buy one I will post some pics of the old shaft in a couple of days.

ProductUser,

$90 for seals and the brass shaft? Aren't there bushings or bearings that the shaft rides on -or- does the shaft run directly in a hole bored in the cast aluminum TB?

You're leaving a lot out when you describe the parts replacement. Mainly, the 2 screws that hold the butterfly to the shaft. In my past non-BMW experiences, they are always very tight, the shaft they are on turns and the end of their threads are usually radically staked or peened over, making them difficult to remove. Then there's the OilHead's throttle stop screw minimum opening setting that must closely match the left side TB's stop screw setting. Because you cannot turn the left stop screw to see what it is set at without messing up the TPS calibration, you need to either equalize or isolate any differences in the BBAS openings from the total air flow to set it exactly. If the stop screw openings aren't equal, the on-throttle synch will worsen with heavier throttle settings (higher revs).

BTW, I just synched my TBs today using the homemade differential water manometer. I use water with green food coloring and the response is immediate. I had just added 2 plastic centrifuge vials as liquid traps in case there's a large difference in the bike it's hooked up to. The large diameter vials prevent the water from being eaten by the motor if the synch is way off. On my TB synch test run, the idle was OK, the on-throttle was off by 1/8th inch. It's perfect now.

Darn CycleRob.......can I borrow that manometer. In my quest to be enviromentally friendly. I will not use water on it and waste a natural resource.......plan to use Guinness and once the idle and sync is completed I will consume the liquid.

Both the bike and me will be happy........if for diferent reasons....

CycleRob wrote:ProductUser,

$90 for seals and the brass shaft? Aren't there bushings or bearings that the shaft rides on -or- does the shaft run directly in a hole bored in the cast aluminum TB?

You're leaving a lot out when you describe the parts replacement. Mainly, the 2 screws that hold the butterfly to the shaft. In my past non-BMW experiences, they are always very tight, the shaft they are on turns and the end of their threads are usually radically staked or peened over, making them difficult to remove. Then there's the OilHead's throttle stop screw minimum opening setting that must closely match the left side TB's stop screw setting. Because you cannot turn the left stop screw to see what it is set at without messing up the TPS calibration, you need to either equalize or isolate any differences in the BBAS openings from the total air flow to set it exactly. If the stop screw openings aren't equal, the on-throttle synch will worsen with heavier throttle settings (higher revs).

My description of how to rebuild the TB was not intended to be a step-by-step process; I was just summarizing.

The shaft resides in a steel sleeve within the TB. Bing said that if the steel sleeve is worn, the TB would have to be replaced.

The stop screws were never touched and I didn't see a need to move them.

The two screws that hold the butterfly to the shaft were staked and it took a little muscle to remove them. I used a tiny dab of blue loctite during installation of the butterfly to the shaft.

I consulted with Bing, my favorite BMW shop and several BMW gurus before I attempted the rebuild. From all accounts, my rebuild was no different from what they would've done at the shop.

ProductUser

I had to drill my throttle shaft screws. They were so tight that half the screw head popped off!

If you'd care to measure some wear try this one....



More info here: http://www.largiader.com/tech/tb

maduko,

WOW!! That's some wear!! Looks like it's about 1/3rd of the diameter worn away. There had to be a lot of rides where the idle returns to a different speed and the engine vibrated on the road because the synch would be near impossible to get even.

ProductUser, I gotta say your last post above is much better. Especially the part where you consulted with Bing, your favorite BMW shop and several BMW gurus before you attempted the rebuild. A little surprising that the throttle stop screw setting wasn't front-and-center in your discussions with them. It's very important that it is set close to factory spec and that it matches on both sides. The new parts swap will provide zero confidence that the stop screw setting will be correct. Especially when the butterfly was removed.
When I first got my bike and adjusted the TPS to cure the surging, it eventually became necessary to "zero set" the TPS with the left TB throttle stop screw backed off. Then you lock down the TPS mounting screws. From there you turn the left side's stop screw in until the TPS's W/R wire reads 370MV to ground. Then with both BBAS set at 1.5 turn out set the other side's stop screw to synch the idle.
Your replacing only the right side shaft is a different procedure and easier to do. Just set both BBAS to 1.5 turns out and adjust the idle synch to perfect with the right TB stop screw. After tightening the stop screw's locknut and the synch is still perfect, use the BBAS to obtain the 1,100 RPM idle. In hindsight, IMO you needed 1 more guru . . . . and I wish I was there.

CycleRob,

I must be missing something or I'm not giving you right information. Both stop screws were not moved during the rebuild. Why would I need to touch the stop screws while rebulding the RH TB? The TB sync, both idle and off idle, was the quickest part of the entire process. My R hasn't surged since the 600 mile service; TB sync is still spot on well with over 100 miles since the rebuild. I haven't noticed any performance issues; acceleration is as it was before the rebuild. All indications are that the rebuild went without a hitch.

I do appreciate your input very much. If you'd like, I can give you a call to talk about this in more detail.

Edit: After re-reading your post, I believe I understand what you are saying. Since I replaced the shaft (the butterfly was not replaced), you believe that would've changed the balance between the two TB's and/or TPS setting that was set at the factory? Thoughts?



ProductUser

That's it, except the TPS setting or calibration will not be affected.

Replacement parts may not maintain the original balanced minimum setting because the old (worn/oxidized?) butterfly disk will not be in the same exact location after the screws are tightened. It will be very close, but without certainty. It is even more likely that the butterfly disk isn't located exactly where it should be because you tightened into place with the stop screw holding the throttle open from (lightly) jammed shut. The butterfly disk holes where the 2 screws go thru allow for a tiny movement so the butterfly can be located dead center with the throttle lightly jammed shut (stop screw loosened) while tightening the 2 screws (no light passes thru). That's how the butterfly disk should be installed. That's where the tiny error can occur and what all this discussion is about. Setting the right side stop screw afterward (if loosened) is described above.

The fact your synch is OK and it runs smooth means the errors I am describing aren't big enough to matter or you got lucky when you tightened those 2 butterfly screws. Only the truly anal would take it all apart again to make the closed shut butterfly disk alignment with the stop screw loosened up. I am not criticizing your work. I'm glad you tackled the job rather than pay the dealer to prolly do the exact same thing. I was just pointing out there are tiny alignments/adjustments that should be made during assembly to make things as perfectly even as possible. You just may have thrown the dart across the room and got it in the bullseye circle. Good job.

CycleRob wrote:ProductUser,

$90 for seals and the brass shaft? Aren't there bushings or bearings that the shaft rides on -or- does the shaft run directly in a hole bored in the cast aluminum TB?

There are indeed bushings that may wear out faster than shaft. The bushings are of two lengths: 9mm and 12mm. The 12mm are marked 812 DUM 0A and can be shortened to 9mm. They can be found in bearing catalogs like this one: http://www.ggbearings.com/products-deta ... =1&Group=1
There's a great thread in the excellent Italian site Quellidellelica: http://www.quellidellelica.com/vbforum/ ... 562&page=2

Removing the axle cap:

Removing the axle and seals:

Extracting a bushing:

Shortening a 12mm bushing:

The whole story (in Italian) is here:
http://xoomer.alice.it/faqqde/FAQ/Corpi ... 0-1150.pdf

Ticker Killer
http://www.bmwandguzzispares.co.uk/bmw/ ... 5_30_FA_75

does it has any sort of help !