Possible surge solution?

[nrpetersen]

I have an R1100RT (2000) that has always had a lot of surge to it. Tuneups have improved it briefly, but it always seems to come back in a few hours.

The original design short cut of having a single throttle position sensor on the left side furnishing information to the engine control processor could be a key to the problem. Some bikes don't seem to show surge, and others have it really bad. What is the difference?

Could the difference be the intake valve clearance differential between the left and right side? Has anyone experimented with this variable? It would be easy to set in say .001 or .002 in. greater clearance in one side vs the other.

Obviously the closed loop operating mode will adjust the injector timing map to get the O2 sensor tripping, and relate that to the throttle position sensor. Is only one cylinder (i. e. the right one) is stumbling during a surge?

Thoughts?

[deanwoolsey]

Well, here's a thought. I've often wondered if a second O2 sensor were placed on the right exhaust and the original moved to the left pipe what might happen. If the two were wired in parallel this might narrow the mixture reading by "seeing" the richest/leanest mixture of the two pipes. The output of the two could be isolated using two diodes. I'm not sure what it would do, but I bet the surge would either get really bad or really gone.

[JimMoore]

Pull the cat code plug and throw it off a bridge. Seriously.

[kgadley01]

Pull the cat code plug and throw it off a bridge. Seriously.

+100 Ditto. loose the cat code plug. My 99 RT had terrible surge. now it is very smooth w/zero surge. PM or e-mail me, and I would be glad to walk you threw the process. Kenny...

[nrpetersen]

I've been reluctant to pull the cat plug since it obviously enrichens the mixture so much that the catalytic converter runs much hotter and the fuel economy deteriorates.

Processors came along just in time to save the piston engine & I believe in trying to keep them functional.

[Kaltzg]

89,000 miles ago I purchased a 1997 1100GS BMW Factory demonstrator. The factory rep showed me that he had snapped one of the legs off the cat code plug and reinstalled the plug. (In effect, removed the plug). I have never had the dreaded surge until at about 70,000 miles when for some reason I installed a new cat code plug. The thing surged like crazy. I trashed the new cat code plug and never loooked back. In 89,000 miles, no surging, no clogged converter, milleage around 45mpg. Life is good.:thumb

[JimMoore]

I've been reluctant to pull the cat plug since it obviously enrichens the mixture so much that the catalytic converter runs much hotter and the fuel economy deteriorates.

Processors came along just in time to save the piston engine & I believe in trying to keep them functional.
You will notice a slight difference in mpg if you do a lot of in-town riding. If most of your riding is rural or freeway, you won't notice it at all.

[jamesdunn]

Pull the cat code plug and throw it off a bridge. Seriously.

The simplest fix is usually the best. I'd pay attention to this post.

[Hoorenga]

Ditto, ditto and ditto on the cat code plug. 1999 R1100RT surged at low speeds in parking lots and backfired coming down inclines. All is good now that the CCplug is gone. I have never missed it or noticed any issues caused by it's being gone in a year of riding. Got great gas mileage on my last road trip. Just smooth slow speed manuvering and no popping coasting down hill.

Doug

[dpilot]

Stop surge by adjusting the airflow to be equal through the throttle bodies
at idle AND held at 2500 by the throttlemeister
Use an old tool called an AirSyn.
Mine surged when I first got it.
Doesn't now.
JimV.

[JimMoore]

I've been reluctant to pull the cat plug since it obviously enrichens the mixture so much that the catalytic converter runs much hotter and the fuel economy deteriorates.

Processors came along just in time to save the piston engine & I believe in trying to keep them functional.
Try it for ten miles. You can always put it back in.

[kenk]

I've been reluctant to pull the cat plug since it obviously enrichens the mixture so much that the catalytic converter runs much hotter and the fuel economy deteriorates.

Processors came along just in time to save the piston engine & I believe in trying to keep them functional.

I'm assuming when you say processors, your talking about devices like Techlusions. I tested all three models of Techlusion, wrote a couple articles on them, and met the inventor Mark Dobeck for breakfast in Kansas City. Internet BMW Riders still has an old 83I article I wrote over 10 years ago still posted. They really need to remove since that version hasn't been available since 2001.

When you pull the CCP on an R1100 series bike, the ECU does default to a richer mixtures. Folks I know that have tested with an exhaust gas analyzer (EGC) say the HC increases from 1.5 HC to about 4 HC. If your using a "processor" like a Techlusion, you've simply added a device on the left fuel injector that increases the duration the injector pintles are open by millisecond. So with a Techlusion, your HC could be anyway from 2.0 HC to well over 4 HC. Unless you have an EGA in your garage, you don't know.

For the newest version, I provided some of the base settings to Techlusion for setup. However, not all R1100 series motors start at 1.5 HC. BMW says the correct HC is 1.5 +/-.5. So, you may be installing a Techlusion on a bike already at 2 HC.

The bottom line is whether you add a Techlusion or pull the CCP, the net affect is about the same. Your running a richer mixture to reduce or eliminate lean fuel surge. The Techlusion's advantage is your able to fine tune at idle, mid and high speed the richening of the mixture.

If your environmentally conscious, your starting with a bike that is currently 15 times the EPA authorized emissions of a mid-size car (.1) and increasing HC to over 40 times the emissions of a small car.

I currently have no surging on my RT with an installed CCP and NO Techlusion. However, I did use all three versions of the Techlusions on my RT for about 80,000 miles. I recently replace a head gasket on the right side and was able to inspect the heads and valves. They were still very clean with normal carbon buildup. However, I kept my Techlusion at lower settings. What fixed my RT surging was a new hall effect sensor (not by choice) and a new Bosch 02 sensor purchased from beemer boneyard.

[ALIENHITCHHIKER]

Sorry to hijack this thread but perhaps others will have an interest.

Kenk, would you share with us your current recommendation for setting up a R259 Techlusion on a R1100 series bike (it's an RT) both with and without using an EGA? (And if I have to pay a shop for use of their EGA, do you feel the results are worth the cost?)

My goal is to reduce surge around 3500 rpm.

Thanks

[nrpetersen]

Obviously I have to try removing the cat plug (which I frankly have not yet done). And I have to think some more about the Techlusion solution(s).

Thanks for all of the comments everyone. I'll still be watching in case there's more.

[genen8kua]

Have you tried the throttle position sensor adjust as found on the ibmwr.org site?

I bought my R1100RT with a Techlusion and a PO's long story of surging early in its life, lots of back and forth with various dealers and BMW, downright wrathy, and a subsequent cure with a Techlusion unit.

But since the Techlusion, the bike had put on more miles and just prior to sale the PO also had Anton Largiader do a tuneup including valves, TPS, and a throttle position sensor adjustment.

I do my own maintenance: I've adjisted the valves and synched the throttle bodies a couple of times since I acquired the bike. With the first valve adjust, I read the Techlusion manual and turned it to the "off" position (still haven't disconnected it). No surging, so something improved over time (but too many variables to know for sure). I should just remove the thing, as it's been a while since I turned it off & no surging problems still. And while the unit is also supposed to provide "accelerator pump" and wide open throttle functions that improve performance, I can scare myself without them, thank you.

So if you haven't adjusted the throttle position sensor you might try that. Trying to get the valves consistent rather than just within spec is supposed to help too, and isn't that hard.

+1 on the concerns about increasing emissions with Techlusions and the like (or removing the CAT plugs). That's why I turned the one on my bike off, figuring that if it wasn't necessary to stop the surging, then it would be nice not to have it. A number of reports do seem to find it effective though.

[abe456]

After you have done a valve setting, do the following:

Remove the TB's, then remove brass bypass screw, use throttle body cleaner on the TB bore, passages, and throttle plate until everthing shines like a new penny. You gotta use throttle body cleaner, nothing else is strong enough. I bet that is where your problem is. Pay careful attention to that little groove in the bore where the TB would rest if fully closed. Make sure there is no black goo left anywhere in the bore, plate or passages. Stay with it until the TBs look brand new. Credit to Pglaves for this item, I never thought it would make such a difference.

Reinstall with new o-rings, intake spigots, tighten carefully, so there is no chance of a lean condition on either side from air leakage. You will never get this bike to behave if there is air leakage. Voice of experience speaking here.

Toss the cat plug.

After, and only after, you have done the above:

Finally, sync the TB's, shut her down wait a few hours, check it again. Keep doing this until the settings dont need to be touched up. Took me 3 times before the bike show any kind of balance stability. Took a total of 5 balance cycles before I was happy with the balance.

Going on my 3rd month (2K miles) now, no surge.

[bikerfish1100]

Finally, sync the TB's, shut her down wait a few hours, check it again.

i was totally with you until this stage.
i can't figure out why you would wait for it to cool off before attempting another synch. the synch needs to be done at operating temp, so i would think that if you want to recheck synch after a first run thru, that you would do better to take it for a test ride, see what you've got happening, and if not happy give it a 2nd shot. no?

[DarkCloud]

Chip and can your bike, you'll love it. More power and no surging, the gas mileage stays the same. JON

[GSAddict]

I've been reluctant to pull the cat plug since it obviously enrichens the mixture so much that the catalytic converter runs much hotter and the fuel economy deteriorates.

Processors came along just in time to save the piston engine & I believe in trying to keep them functional.

Canadian bikes do not even come with the plug OE from ze Fatherland.
Loose the cat plug, change to Autolite 3923 sparkplugs, enjoy the increase in response and don't sweat the possible slight decrease in fuel economy. :whistle:whistle
BTW: Lean mixtures damage piston engines, not richer ones.

[abe456]

Letting the bike cool down and then re-checking is simply a verification step. If you get consistent balance by doing this a few times, you can button her back up knowing the TB balance is good to go.

I think sometimes we get in a hurry at the sync phase with the heat, noise, and touchy response of the throttles. I know I do. I have often had to take the tupperware back off and do the sync all over again because something wasnt set properly - by me, of course.

Pglaves recommends off-idle cable sync at about 1500 - 2000 rpm. That is a very touchy range, even the slightest turn of the RH cable screw will affect sync. It takes several iterations of idle balance and cable balance before she will settle down and give repeatable results. I have often found that, a day later, the balance would require a tiny tweak again. After a few rounds of this, the tweaks get smaller and smaller until she settles down and gives reliable balance results. Dont give up until you get good balance and idle and off-idle, and can get the same results after a cool-down and warm up cycle.

[abe456]

I need to clarify one thing: when I say cool down, I also mean warm it back up the same way you did the previous sync, which is about 20 minutes or so of riding to bring everything back up to sync.

I didnt mean to imply you should do a cold-engine sync. Just go through a few cycles of warmup - cooldown to see if the bike can be reliably sync'd. If it works, great. If not, you got more work to do, brother.

[riderR1150GSAdv]

Losing the CCP is the least expensive way to improve the surging issue. My 04 1150 RT did not come with one and neither did my 06 1150 GS.
However, I did experience some surging recently and after a thorough cleaning of the Throttlebodies it went away.
I took the TB's off the bike and removed 77K miles worth of gunk.... :blush

[kenk]

Sorry to hijack this thread but perhaps others will have an interest.

Kenk, would you share with us your current recommendation for setting up a R259 Techlusion on a R1100 series bike (it's an RT) both with and without using an EGA? (And if I have to pay a shop for use of their EGA, do you feel the results are worth the cost?)

My goal is to reduce surge around 3500 rpm.

Thanks

Your R259 should have come with recommended settings. This should be the recommended settings for your bike.

Red - 4:30
Green - 2:30
Yellow - 3:30
Cruise - 8:00

However, for some bikes, this setting is too rich. If it's too rich, try these leaner settings. I would simply read the plugs to determine if the settings are too rich for your bike.

Red - 2:15
Green - 1:45
Yellow - 2:45
Cruise - 6:30

If your bikes works well with one of these two settings, I wouldn't waste the money having a dealer check your emissions with an EGA. If you live in a state where emission are checked, I would simply keep the CCP and reinstall before emissions testing. Naturally, you would also turn off each pot on the R259 as well.

[ALIENHITCHHIKER]

Kenk, thanks for your suggested settings.

Your mention of reinstalling the CCP prior to emissions testing sounds like you are running a Techlusion as well as having pulled the plug.

I've run my 1100 this way for short periods (with Tech settings closer to your lean suggestion) and was impressed with the performance. I reinstalled the plug out of concern that the combined mods might be way too rich for the cat converter.

Any thoughts?

[kgadley01]

Canadian bikes do not even come with the plug OE from ze Fatherland.
Loose the cat plug, change to Autolite 3923 sparkplugs, enjoy the increase in response and don't sweat the possible slight decrease in fuel economy. :whistle:whistle
BTW: Lean mixtures damage piston engines, not richer ones.

+1 :bow

[j-budimlya]

I have been through this dance with a '95 R1100R. I tried the Techlusion R259 with a thorough trial of ranges of settings, with stock exhaust and completely modified exhaust. I tried it with a CCP and without. And for me, the best solution was stock with the CCP....and new throttle cables and a careful valve adjustment and TB sync. The missing key for me was new cables....when the cables get old they fail to return to the same position consistently and getting a nice consistent balance is nearly impossible.
I'd stay with the stock setup and just go through a thorough cleaning, new cables and then a complete tune up...following the book carefully. Something as simple as releasing the tension from all of the throttle and fast-idle cables before doing the sync can be critical to the successful outcome in my expereince.
BTW, an R259 set to recommended settings carboned up the motor facter than anything I have ever seen. I had to do a careful decarboning of the motor to eliminate engine knock to eliminate this problem....running real rich is not good for these motors....

[Happy Wanderer]

I have a '96 R1100RT. It's got the surge problem real bad so I have been reading the impressive number of threads on the subject. Mine surges from 2000 to 4000 RPM in every gear. Even at highway speeds of 70 to 90 MPH it is always there. Just less noticeable in 5th gear but it is there.
I have tried the following to no avail:
- Removing the sensor on the air box under the rider seat. I was told this would force open mode. This seemed to help for about 4 minutes. The surging resumed.
- Installing Autolite 3923 plugs. This seemed to help a bit with acceleration but when I broke down in Chico CA the boys at Ozzie's tossed them in the trash and put Bosch plugs back in. "These are Ford plugs! Don't be silly..." said Mike the head mechanic. He's awesome. Everyone at Ozzie's BMW in Chico is awesome. Best BMW shop in the world IMO. But Bosch or AutoLite, no difference with the surge.
- When I called Ozzie's and talked to Mike from the Oregon Coast on my way home because the surge was making me crazy as I crawled up the Coast HWY 1 (all those towns and lights!) he said reset the computer. It will "learn" new settings. I was told to take the tupperware off the left side and disconnect the battery from the bike and ground the (+)ve cable for 30 seconds at least. This discharges the volatile RAM settings. I have no idea what Motronic unit or version I have or if twisting the throttle full on twice with the key on or the key off or pulling Fuse # 5 after pulling the CAT Plug/Relay ??? would reset everything as I read in another thread. Powering it off sounded reasonable to me. It's a computer. Take away power and the volatile RAM dies right? Anyway. It got better for a very short time and then went right back to surging.
- I bought a lovely set of CarbTunes from Belfast Ireland (awesome carb synch tool!!!) and set up the valves four times to get them absolutely perfect. This tuning effort made the biggest difference of all in terms of smoothness but the surge does not go away. It just surges more nicely... Valve adjustment and throttle body calibration has been the biggest noticeable factor so far for my bike.

- After reading that I just should remove the CAT plug, pull fuse 5 for ten seconds and that would fix it I though OK. Well, you might find this funny but I discovered the CAT plug is not even there! More reading and I found a post from a guy in Sechelt BC saying that Canuck bikes have no CAT plug... They come that way. So I wonder if pulling Fuse 5 does _anything_ on Canuck bikes.:dunno

- I have bought a used Techlusion 259 but am afraid to install it because of the dire warnings about ruining my Catalytic Perverter and the environment.:nono

- Yet another thread suggests cleaning the throttle bodies but last time I looked in there, they weren't dirty. The air mixture screws were filthy though so I cleaned them. The O rings were fine. This made no difference either.

At this point the only other suggestion I have read is that the injectors themselves can cause problems and they should be cleaned. I don't know how to remove them exactly (supposed to be easy) and I don't know what to clean (soak?) them in. One thing I did notice is the right one clicks more loudly than the left one but supposedly this is not important. As long as they do click is what matters.:dunno

Frankly, I am at my wits end. Maybe the O2 sensor is bad? How to check I wonder. The dealer gets no fault codes for my bike even without a CAT plug. The plugs are always lean and clean looking to me but with today's unleaded gas you cannot tell much from a plug.

Sorry bout the long post but hey, it's good to know what has been tried and I actually love this bike. It "fits" me and is awesome for riding to rallies and other long trips. My trusty '82 R100RS is always at the ready, but the RT is a highway eating machine.

If anyone out there has an idea or advice on the injectors or something else I might look at or try I am all ears!:ear

[nrpetersen]

I also had an unreal surge on my 2000 R1100RT (24000 miles) that I eventually thought might be caused by one cylinder cutting out when in the 2700-3200 rpm float. Then I realized that since there is only one digital feedback transducer (the O2 sensor) for the two cylinders, anything that delivered an individual injector fuel pulse error based on the single throttle position sensor, could cause such a stumble. Otherwise the bike is stock. The blue plug is installed.

This winter I measured the existing intake valve clearance settings and found that the left cylinder (the one with the throttle position sensor) was about .015 vs about .007 inch on the right. I thought this might be slightly advancing the right air intake, which given the equal injector pulse lengths, would cause the right cylinder to run lean enough to cause it to misfire.

I proposed this hypothesis to our site's engine guru Twisty, who has a lot of experience with processor control of engines. He was not optimistic, but WTH - I said I'd try it and post the results.

I very very carefully set the right cylinder intake valve clearance to be very slightly greater than the left cylinder (.008 inch vs .007 inch for the left). This I reasoned would make the right cylinder run ever so slightly richer than the left - even after the closed loop fuel map updated based on the O2 sensor feedback.

The snow in the yard has melted so the test runs were just yesterday. NO SURGE! :dance and it didn't come back in ~35 miles. This is with the original Autolite plugs with ~20,000 miles on them. It is as smooth as my K1200LT with a slight instability coming off closed throttle at ~ 2000 RPM (what am I doing down there?)

My previous surge was worst at higher temperatures, so it will be interesting to see if warmer weather causes it to come back. I also cleaned the BBS - they were somewhat carboned up. I was going to do the zero-equals-zero tune but found the TPS was already at .363 volts at closed throttle so I speculated that maybe it was close enough. Otherwise I have yet to do anything more than a visual and seat of the pants balancing of the BBS.

My recommendation - Carefully document your existing intake valve clearances. Maybe clean your injectors, and as a last resort, switch fuel injectors left to right.

And - tell us what clearance you find, and the result of differential settings. No warranty in this. YMMV:dunno

See update in post # 40.

[Happy Wanderer]

OK, I'm game. I could try increasing the intake valve(s) clearance by a thou and see what happens. I just got in from the shed after removing the left injector for a looky look. The tip looks nice and clean but I did notice the rubber shoulder seal in the throttle body was a bit hard. Probably original. I think I should replace both sides with new ones just to make sure there is no vacuum leak there. The plastic bottom of the injector is a bit dirty so maybe my throttle bodies are too.
I could not remove the fuel line from the injector itself though. I removed the upper most clip as per the repair manual and thought it would slide out of the injector but after pulling as hard as I dare I remembered someone saying don't ever over bend or break those plastic fuel lines or you'll be sorry!! So I stopped. I have no idea how to separate the injector unit itself from the fuel line other than pulling harder. ? Is there a trick to this? I would like to soak them in cleaner or perhaps even take them to a fuel injector rebuilder here in town. Apparently they work magic on injectors of any kind.

[j-budimlya]

Two things that I have not seen mentioned yet, 1) have you checked for inlet vacuum leaks? Any leaks on the inlet side of each cylinder cause all kinds of problem, I have had to replace these rubber seals on my bikes; and two, what has been done to increase airflow(engine breathing) is the exhaust stock? is the airfilter stock? Anything that increases "flow" also increases the difference between the cylinders, because ultimately this is what causes the surging and vibration. Also, have you inspected the pistons for carbon buildup?? If the bike has been operated with a significant imbalance, chances are that one cylinder has a carbon buildup and this will cause all kinds of imbalance and surging problems. You can inspect through the spark plug hole...look carefully for differences. Three possible "fixes", 1) run the bike very hard for an extended trip of 1000+ miles, 2) use the water torture treatment to knock it off the piston, and 3) remove the heads and clean if off. To one degree or another, all three methods improve the situation. But they are listed in reverse order of effectiveness. They have all improved the bikes performance at one time or another. Just running these motors at 4,000+ rpm for a few long trips always makes them run better....and removing the heads and cleanning off the carbon makes them run like new(almost).

Don't give up, you can make everyone of these bikes run great if you just stick with it. If you are frustrated, don't be afraid to check the compression on both cylinders....sometimes there is a problem and this could always be a watchout.

[Kaltzg]

First, I must apologize to the author of this following article as I don’t recall who the author is, but this procedure helped me out immensely. First off, it is easily reversible so if it doesn’t work for you, no harm no foul. In my case while checking for the appropriate voltage I found that it was all over the place. Every time I released the throttle I got a huge voltage difference which indicated that the TPS was bad. I replaced the TPS, set it to the .395 voltage as indicated in the article and “Happy Days” ever since. Now some 70,000 miles later when I start feeling a bit of surging a simple valve adjust and throttle body sync it’s purring like a kitten.:p

“The fuel injection uses the TPS to indicate throttle opening, so it can be adjusted to increase the amount of fuel without increasing the amount of air. The results are a richer mixture. The procedure is simple. Pull your left fairing cover. Get out your trusty DVM and attach the minus side to the battery negative terminal. Attach the plus side to a pin and stuff the pin into the end wire of the TPS connector (red/white). Turn on the ignition, but don't start the bike. The DVM will now read between .300 and .400 volts. The optimum setting is .395. Loosen the screws that hold the TPS in place, and rotate the TPS until you get 0.395 volts. Tighten the screws and crank on the throttle a few times. Reset the screws if required to get the correct voltage."

[nrpetersen]

On reflection about this problem - I wonder if a lot of the problem might be the difference in flow calibration between the two injectors, since they both have to have the same pulse length at any given time, since there is only one oxygen feedback sensor.

If there is a difference in the injector flow calibrations, depending on which one delivers the greatest amount of fuel, one cylinder will run rich, and one will run lean. The throttle position sensor will optimize the closed loop map for the average mixture. Of course it optimizes to a stochiometric mixture (14.7 air/fuel ratio). But this ratio is numerically much closer to lean stumble, than it is to stumble from running rich.

If it happens that the right cylinder injector is the one that is shorted on fuel delivery, it would be the first to stumble. If the left cylinder is shorted on fuel delivery, the map would be simply update to get stochiometric operation once again.

My hypothesis - Stumble/surge can be caused by cutting out of only one cylinder - and it is most likely the right one. All it takes is a difference in the flow calibration of the injectors.

The solution is to swap the injectors left to right. How can this be done without wrecking the fuel pressure regulator or lines?
Comments?

See update in post # 40.

[dbrick]

The solution is to swap the injectors left to right. How can this be done without wrecking the fuel pressure regulator or lines?
Comments?

Am I missing something? Changing the injectors side-to-side should be simple: disconnect the electrical feed at each injector, disconnect the fuel line at each injector, swap the injectors, reconnect. You never touch the regulator.

[nrpetersen]

I didn't try this, but just how do you disconnect the fuel line to the injector? It wasn't clear from Chiltons. I gather Vancouver BC (156327) had trouble doing this.

Obviously as noted above, an airleak in the intake hose system between the cylinder and the throttle body could cause similar problems.

[deanwoolsey]

If you lean out any motor enough it will surge at steady throttle. This is pretty easy to duplicate on a lawnmower engine where you can access the idle mixture screw. So we know that lean mixture causes surging. Now, since the two injectors are driven from a single O2 sensor they produce the same amount of fuel (pretty close anyway) delivered to both sides of the engine. So the question to me is what happens when the valves are not equal? The short answer is it changes the fuel/air ratio. Since the same amount of fuel is delivered on each side, when the valves are loose on one side it causes a richer mixture (relatively) on that side. Think about it. Less air through the throttle body yet the same fuel delivery to both sides. This also causes a power difference between the two cylinders. No wonder the Motronic can't make up it's mind. So I suppose my point is that valve setting is critical comparing side-to-side. Valve setting also directly influences the balance or indicated balance of the throttle bodies. Sloppy valve adjustment will cause an inaccurate thrrottle body reading. Personally I use a deep dish socket with the side cut away so I can apply my torque wrench while holding the set screw exactly where I want it with the allen wrench. The closer you get the valves the better. Anyway, it sure can't hurt.

[jamesdunn]

My thoughts? Lose the cat code plug or, just use Autolite 3923's. Or both. That is about as good as it will get in terms of surge and as good as it needs to be....seriously. In conjunction of course with a well tuned motorsickle.

[Happy Wanderer]

Update from 156327. (I must have missed something signing up to get a number as a user ID... can't find a place to change it either... oh well)
I should mention a few things more. I have read oilhead valve clearances for dummies and followed the advice. I have four feeler gauges with nifty plastic covers over half of them so that I can do both intake and exhaust valves at once and I have an excellent CarbTune unit. I have adjusted and synchronized the valves and throttle bodies several times and the work was checked by Ozzie's. No flaws were found. The valves were perfect and the balance was bang on. This engine was top end rebuilt at Ozzie's in Chico CA last September. Carbon and crud in the cylinders is not an issue. Compression is not an issue. I seriously doubt that there are vacuum leaks in the intake hoses as the bike is in excellent shape. I am going to replace the O rings where the injectors seat into the throttle bodies however, because they felt a bit dry and hard for my liking but I really don't think they leak. Just got the parts today.
Also, this is a Canadian 96 r1100rt and it came with NO Cat Code plug from the factory. It is hardwired for closed loop brand new. I checked today at the dealer by looking up the VIN number and the CAT Code plug is an option, it does not come with the bike.
Thanks to npeterson, JimBud, Gail Katz and that fella from Sechelt for all this great input so far.
The throttle position sensor was a new idea to me. This morning I filed down a copper strand from a house ground cable that I could slide into the position sensor connector without damaging it and make great contact. Being a bit over anxious (this could be it!!!!) I forgot to measure what it was before I loosened the screws and it moved before I could take a reading. So I don't know what it _was_ but anyway, I adjusted it to 0.395 VDC as recommended. During my ride today it surged as bad or worse than ever. BUT what I did notice is how hard it was to get the same reading after cranking the throttle wide open a couple of times to check the fall back voltage. It changes a bit which I found very interesting.
My Plan now is to:
1) Install the injector shoulder rubber seals just to be sure there is no vacuum leak there. Ride the bike. If it still surges (and I think it will) ...
2) At the suggestion of Shail's Motorcycles I will replace my throttle cables. Apparently BMW recommends these be changed at 40,000km because if you don't guess what? They say the bike may surge... If it still surges (well, I think it might) ...
3) Install the Techlusion R259 since I have one and both BMW shops I visited today said they have fixed a LOT of 1100 oilheads with it. Ride the bike. If it still surges I think I need an expert mechanic or divine intervention. Or maybe just live with it because I really do love this bike. If it wasn't for the surge, it's the best thing I have ever ridden except for that 2009 R1200RT that Ozzie's lent me while they fixed mine last September!

[nrpetersen]

156327 (Its like a prisoner number or something!) Keep track of where your injectors are presently located and if you can, reverse them when you put in the new seals. Let us know what you find out. THX

See update in post # 40.

[Happy Wanderer]

Thanks npeterson for your ongoing interest in my surger.
Yesterday I asked my local mechanic how to get the fuel lines out of the injectors after removing the metal retaining clip. He said PULL HARDER. Well, I thought I was pulling hard enough to nearly break the plastic fuel lines so I asked him "what if I break one?". His answer: "Then you are REALLY in deep S&%*!"
I take that to mean really deep expensive S&%*. I was hoping to hear from someone who had replaced or serviced their injectors because it is hard to believe they are so hard to dis-connect. There must be a method to doing this without breaking a fuel line. I do not have a Haynes or Clymer manual, only the official BMW shop manual and it has no procedure detail. Just do this, remove that and so on. So I am not going to risk making things worse until I figure things out a bit more. But yeah, I would gladly reverse them. They should work exactly the same on either side though is my view. The injectors are one part number and thus must be interchangeable.

[nrpetersen]

OK guys - I gotta eat some crow here.

Private communications with a processor controlled engine guru and an afternoon of pondering, revealed to me that any oxygen sensor feedback system will actually end up optimizing the fuel map based on the leanest cylinder, not the average as I had said above.

This is because a single oxygen sensor is just that - it toggles as soon as there is any oxygen in the exhaust no matter which cylinder it comes from. Obvious to me now is that the leanest cylinder is the one that puts oxygen in the exhaust first. The fuel map then will be updated based on the leanest cylinder.

The other cylinder by definition will run richer. This means no cylinder should ever run extra lean - i. e. beyond stochiometric (which is 14.7:1 air fuel ratio in which all of the oxygen is "burned").

Personal experience with aircraft engines shows they get a little rough when leaned to stochiometric. They get even rougher when operated still leaner although in many conditions, best fuel economy can be obtained by running extra lean.

Later BMW R bikes even use two oxygen sensors so each cylinder's fuel map can be different.

The oxygen sensor does not average the combustion process. It looks for oxygen from any source.

So - disregard my earlier calls for injector fiddling or even swapping.

Now if I could just figure out why my 2000 R1100RT runs so much better now than last fall. Might there have been an intake manifold air leak? I didn't think so but?:dunno

[Happy Wanderer]

Today was a very interesting day. After checking three bikes out I learned a few things. In Canada, R1100 built up to 1996 have no O2 sensor. When I pulled my tank off today to hook my Techlusion R259 unit up I found the O2 sensor connector cable tied to the right side frame with a factory rubber plug over it. It goes nowhere. So the Techlusion R259 would never work on a pre 1997 bike. I checked out mine and a 95 R1100RS today and they are the same. No CAT plug. No O2 sensor and a rubber covered O2 sensor connector. They shipped from Germany to Canada this way.
So with no fuel map and no input from an O2 sensor to change anything these bikes just run a bit rich normally. You can imagine my surprise after all this investigation.
Obviously my surging problem lies elsewhere and it's back to basics. BMW recommends new throttle cable installation at 40000km or surging may occur according to a service bulletin I am told, and mine has 66000km so I will install a new cable tomorrow along with the new injector seals. I am also going to do another thorough valve adjustment and synch the throttle bodies just to make sure all is as it should be.
Anybody need an R259 Techlusion controller? :p

[Happy Wanderer]

Surge problem update:
Well, over the last five days or so I:
- removed and thoroughly cleaned the throttle bodies
- replaced the throttle cable
- installed new shoulder washers and O rings for the injectors
- reset the TPS (throttle postion sensor) to 0.370 VDC and tried a few settings between .370 and .400
- adjusted the valves
- synchronized the throttle bodies

The result was a bike that runs exactly the same as when I started. Actually it surges a bit worse now than ever and seems to almost cut out sometimes like a fuel flow problem or spark problem but I think it is just excessive surging or "hunting" as some call it. I am extremely disappointed after all this careful work but not giving up just yet.
Next Steps:
- Get out the WD40 and spray around the inlet points and throttle body bushings to check for vacuum leaks but with only 66000km on the bike I doubt they leak.
- Next I think I will go ahead and break the almighty BMW blue gunk seal on the left throttle body stop screw and perform Rob Lentini's zero-zero procedure and try re-synching the throttle bodies again. I doubt it will help but at this point it is worth a shot. This bike is long out of warranty anyway.

I am starting to think the problem lies elsewhere. Maybe a bad spark plug lead or a flaky injector? Not sure how best to test them on this particular bike (96 r1100rt) so more reading if the above two more steps yield nothing. After that well...:dunno

[cycleman2]

Use an unlit propane bottle, one you would use for soldering, for checking vaccum leaks. Turn the propane on ( don't light it ) as pass it around the intake, injectors etc with the bike running. If the idle speeds up you've found your vaccum leak.

WD40 is much messier and doesn't always work.

[DarkCloud]

Does the TB synch hold at all rpms? If it doesn't , you have a vacuum leak.

Does the surging go away at 3900 rpm?

If those vacuum caps that you remove for the TB sysnch are bad, it will surge.

Bad spark plug wires and the stick coils can cause something similar to surging.

Can you borrow a non surging R1100RT and sytematically pull parts off of your bike and put on the borrowed bike to determine single bad parts on your bike? JON

[Happy Wanderer]

Today I checked for vacuum leaks. There are none as far as I know. I used WD40 since most any solvent will cause an increase in RPM when sucked in near or around the manifold.
I also did Rob Lentini's zero-zero procedure. This was interesting. It is quite tricky getting the TPS to stay at 10mV and every time the throttle is twisted up and let go it seems to settle at +/- 5 or 6 mV from the last time. Eventually you get there. Then I set the throttle plate to a reading of .370. When I fired the bike up and set the right side up with my manometers I had a pretty nice idle of about 1100. Just right. Next I opened up the air screws 1.5 turns and proceeded to do the synch. The usual frustrations trying to get it just right. The whole throttle cable and control/adjustment setup on '95 and '96 RT bikes is just terrible in my humble opinion. Very difficult to get it right and even the slightest twist as you tighten things up throws it off again. Trying to get done without overheating the bike (I don't have a large fan, this is Canada for heaven's sake!) is not easy. Again, eventually you get there but it takes a lot of fiddling and patience. At the end of the day, the bike is running as well as it every has, but it still "hunts" and surges. Also, once it warmed up thoroughly for some reason I now have a idle of around 1400 RPM. I suppose I can lower the idle but this will require doing the synch et al all over again. Anyway, I am slowly starting to beleive these particulare bikes have a built in defect of some kind. The fuel map is wrong perhaps. The throttle setup is incapable of steady tension on both throttle bodies perhaps. Gsaddict suggests riding with a TwinMax connected to see what is going on. Good idea if you have one but I use the CarbTune product which is a good mercury free manometer and it is accurate. I might go out and get some Autolite 3923 plugs and throw them in but I tried that last year and it did not help the surge really. At this point I am out of ideas.

[j-budimlya]

Did you mean it when you said you setup the bike with the airscrews closed and it idled at 1100 rpm and then you opened the airscrews 1 & 1/2 turn and it now idled at 1400 rpm??

The bike should not run with the air screws all the way in??? I know the shortcomings of the early oilhead throttle control cables; did you clean the throttle control system well....from the grip to the Bowden box, etc? The system must return to the "stops" every time and reproducable to work right....

[Polarbear]

Many of which, if not all have some merit, but you know something? Its an overworked item, for a simple problem. The injector'd beemers have a fuel system computer reading, mapping the fuel usage, yes. We all agree. Its always trying to optimise the gas usage and clean air tailpipe emmisions. The surge is the two sides battling to become one fire unit and its so very tricky to convince the computer this is being done! Its an extremely simple idea thats so very confusing to so many. A "cable"/mechanical operating device to the throttle bodies is a weak link, in the world of electronics taking over fuel system management, yes? Simply put, the computer has no variances to "perfect" and the cable does!!! To mechanically set this cable to match the computer needs is a challenge of magnatudinal proportions. BUT, all this said and with hands of masterfull touch, you might achieve a non surging twin someday. I got lucky and found it on my R1100GS,1995 model. The CCP gone too and the gas mileage is your simplest, easiest scale to use regarding how clean your bike is running. Use nothing else as a guide. I'm a firm believer the cable to the bodies is the issue, as was in my case. Some have had other sensors fail too, but the cable is a first approach. Many many dealers have never had, or perhaps even never stood a chance at setting cables right! Its like I said above, computer vs. mechanically faulty cable that has variances. A tough battle. The NEW twins have a cable too, but the computer programs have been changed(gotten better with age) to have considerations(sensors) for this weak link....Cables are steel, steel strecthes with heat applied and cooling again. This may seem tiny, but enough to make your bikes fuel computer KNOW it! All opinions here of course. I'm just another owner, trying to figure it all:). Happy Trails, :usaRandy, Too many BMWs and thought going on at my place:):usa

[Happy Wanderer]

To answer Jim Bud, yes, the bike will run with the airscrews turned all the way in. Some will not idle at all and for those you simply turn both screws out 1/4 turn at a time until they will. After you zero the left side and then set the throttle plate to read .370 VDC you set the right side throttle plate screw using manometers and with the air screws all the way in. See "Zero = Zero" Method for Adjusting BMW Oilhead Throttle
Position Sensor To Reduce or Eliminate Engine Surging - Rob
Lentini here:
http://www.ibmwr.org/r-tech/oilheads/R11Manual/Oilhead_Maintenance_2-25-02.pdf
It's the best throttle balancing procedure out there and it does work. The idle speed got higher somewhat due to turning the screws out to the initial 1 1/2 out but mostly because at that point the engine was finally warmed up properly. I started with a cold engine knowing how long it takes to get to the point of synching the bodies which must be done warm.
To answer Polarbear, I also think the cables themselves are one of the biggest problems. That's why I installed brand new ones which are the teflon type and much better than original. The early 96 RT has a single cable that wraps around the left throttle body and then crosses over to the right one. It is a very poor design and the path it takes to get to the pull points is not good either. I noticed that the air intake tube that connects to the air box for example actually pushes on the left side throttle cable just above where it connects to the adjust point. How stupid is that? I warmed mine up with a heat gun and put a slight depression in it using a socket extension as my push mold. That alleviates the pressure on the cable a bit which helps. There is a reason BMW went to a cable distribution box in the middle under the battery on the 97 RT. In Canada, they also added the O2 sensor (mine has none) and the CAT plug (mine has none). There is NO doubt in my mind these 95 and 96 had un-acknowledged problems with the fuel injection and fuel control designs but still I persist because I also have met several folks at rallies that have 95 and 96 RTs that do not surge.
All of that said, as of last night (did everything again... just to be sure) the bike is running smoother and accelerating as well as it ever has. So all this care and attention to fine tuning has some benefits. :dance But the idle is still way too high (gotta fix that today) and the bikes still surges. Might have to just live with that. :dunno

[LCBIKEMAN]

Much appreciate the link to the Kulow maintenance manual. I shall use it to check over my bike.

[Polarbear]

It took months and even a year or so, but I finally learned with MUCH trials and tribulations, to set my TBs and I must have gotten lucky. My '95 R1100GS was a non surger after a lot of tinkering, scrathing my head too much and pulling my hair out! Its no question, a brain tease. I spent way too much time having to do this on a bike thats supposed to be near perfect, from Germany? I still loved the bike, with all this said and rode her 97000 miles and the new owner was all smiles as he rode her away:). Randy:usa