R1100RT Right TB air leak.

[LAR2599]

I know this has been beaten to death...but I know I have an air leak...but can't determine from where. I don't want to spend a $100. to repair the TB and find the leak is the inlet manifold and vice versa...so any suggestions on how to pinpoint this would be appreciated. Valves adjustments are spot on, good compression, new plugs, air filter all the things mentioned in previous posts. Bike vibrates, surges and backfires. Bike runs smoother cold, idles (rough) with BOTH BBS all the way in and when on a carbstick....it sucks fluid to the left side almost instantly...at idle or at 4000 RPM. But other than the vibration...it runs strong

[RTCHIEF]

smoke test?

[OoPEZoO]

The easiest way to find any sort of an air leak is with a can of carburator cleaner. Get a nice steady idle going and then start spraying around any questionable connections. If you you hit a spot that causes the idle to climb then you found your air leak.

[eddd]

The right TB wears at the shaft. This is the most likely place for your leak. You don't mention your mileage, but I have 144,000 miles on mine and just replaced the right TB. The wear on the one that came out was very significant.

[JonathanE]

If you don't have carb cleaner handy, I've heard that a little propane works as well. I haven't tried it.

[LAR2599]

140,000+ miles.

[eddd]

140,000+ miles.

 

At that mileage it is almost certain that the shaft is badly worn. Pretty easy to confirm...just remove the TB...an easy job.

[Yeeha! Stephen]

You can rebuild them with kits from the Bing Agency in OK.

 

http://bingcarburetor.com/bmw/bmw.html

 

http://bingcarburetor.com/pdf/throttlebodykits.pdf

 

Get the Model # off the bottom of the TB and tell the folks at Bing you need the repair kit.

 

 

..

[OoPEZoO]

I was thinking I was having the worn throttle body shaft issue on my bike. I have ~125k miles on it right now and I am having some weird idle hunting issues that made me think I had an air leak. I tore the throttle body apart last weekend and the damn thing looks almost perfect. I was expecting a heavily worn shaft, but it looked good enough that I just put it all back together and put it back on the bike. I think I am going to buy a rebuild kit for them this next winter to replace the seals, but I saw no reason to replace the shaft.

 

I have seen pictures of bikes with less miles and worn shafts, so I guess the only way to be 100% sure is to take it apart and see for yourself.

[Yeeha! Stephen]

Remove the TB, remove the decorative cover from the end of the shaft and the circlip holding the shaft in.

 

Remove the 2 screws holding the butterfy in the TB throat, and remove the shaft.

 

Lay out the parts in order of removal and reassemble in that order with the new parts.

 

 

.

[Yeeha! Stephen]

I replaced the bushings that the shaft rides on also.

 

They don't come with the kit, but I sourced them online here...

 

http://www.ggbearings.com/technical.php

 

http://www.tracepartsonline.net/(S(woqk0l45a5fwgybvxoewpsnq))/ws/ggb/index.aspx?lang=en

 

Go to this page and click DU bushings Meteric and look up DU 812's,

 

The are 8mm ID, 10mm OD and 12mm long.

 

I heated the TB with a heat gun, and used a 3/8 coarse tap to remove the old bushing. While the TB was warm, I pushed a frozen new bushing in with the heel of a screwdriver.

[Yeeha! Stephen]

Photo of the Kit and also TB parts in order of removal...

[Yeeha! Stephen]

My shaft was worn, allowing the cable pulley to bounce and the butterfly not to seal properly. Made throttle sync almost impossible.

 

While syncing I couldn't get a good balance. I saw the cable pulley bouncing and literally put my finger on the pulley to stop it.... instant balance! Duh!

 

Photo of worn shaft.

[Yeeha! Stephen]

There is some tricky stuff for the Throttle Postition Sensor side, but if you go to the Hall of Wisdom on ADV rider, there is a write-up for resetting the TPS.

 

I did this and it worked just fine...

 

http://advwisdom.hogranch.com/Wisdom/tps3.1.pdf

 

 

[flars]

"...There is some tricky stuff for the Throttle Postition Sensor side..."

And of course, the left side rarely needs rebuilding since the TPS holds everything stable, so this task shouldn't be necessary.

[LAR2599]

Continuing saga...took R-TB off...butterfly shows no sign of being loose. Put sealer on the inlet manifold to head....no improvement. When spraying for leaks...no change in idle.....but still very little vacumn from right side.

[Ken H.]

Was just re-reading the original post where you say, “...both BBS all the way in...” Why this? Typically you start with each around 1 ½ turns out. I’d say put them there as a starting point.

 

“it sucks fluid to the left side almost instantly...at idle or at 4000 RPM.” Concentrate on getting sync balance (with the cables) at higher RPM, then come back to at idle and adjust the BBSs.

 

[oldyam]

Was just re-reading the original post where you say, “...both BBS all the way in...” Why this? Typically you start with each around 1 ½ turns out. I’d say put them there as a starting point.

 

“it sucks fluid to the left side almost instantly...at idle or at 4000 RPM.” Concentrate on getting sync balance (with the cables) at higher RPM, then come back to at idle and adjust the BBSs.

+ 1

 

adjust the cable to close the butterfly on the RH TB to raise the vaccuum and equalise the fluid levels

[OoPEZoO]

+1 for starting with the BBS's about 1 1/2 turns out. I'm not even sure my bike would even idle if both BBS's are all the way in. Having them them all the way in should make your bike just about or completely stall out when at idle.

 

Is it possible that the air passage in the right throttle body for the BBS is partially blocked? Its really going out on a limb, but I suppose many years of crud could build up to cause a partial blockage.

 

 

[LAR2599]

Hence the problem. Why will mine idle with both BBS all the way in. Believe me I have tried everything. TB's are clean, ether cause no rise in idle.Trying to set the sync at high rpms doesn't work because it sucks the liquid almost instantly to the left even if I switch the hoses. The right seems to have very little vacumn.

In last year two dealers have synced the TB and bike still rough. I have decided that vibration is just part of my future and am giving up.

Thanks for all the input though. I'm going riding!!

[oldyam]

It sounds very much like a case of the butterfly's having been adjusted to give an idle setting with the BBA's fully closed, which may have left the TPS misadjusted.

 

It may also be an idea to check the vaccuum port on the RH TB is clear and not blocked / partialy blocked.

 

I would also clean the BBA's & visually inspect the butterfly's and their relative positions.