R1100s 2005 won't rev smoothly

[Joepi5]

Hello everyone!

Currently I'm working on a new to me 2005 R1100s that has been neglected for some time (used a lot in wet weather and road salt).

So far all the consumables have been replaced (oil+filter, air filter, spark plugs, transmission oil, battery). Besides that I checked and adjusted valve clearances and did a synchronization. But I keep having a problem when trying to reach higher rpms.

What happens is that everything goes smoothly until about 4-4.5k rpms after that it seems to hold back a bit up to 6-6.5k rpms. After that it's surging and generally not being smooth. But it will reach to above 7.5k rpm (at least in gear 1, 2, 3 and 4. No roads around to test the last 2....)

What this causes during riding can be a little bit dangerous while you reach the 4.5k rpm mark at lean through a turn. My question is if this is normal for this bike? Is there something else that absolutely needs checking?

Fuel consumption is also rather high at roughly 32 MPG. Is this to be expected?

Many thanks in advance!

[Joepi5]

I forgot to mention that this is most prevalent between 30 & 70% throttle input. If I take it really slow it seems fine. If I absolutely hammer is there is very little stumble around 5k(ish) RPM and it keep pulling hard

[908/930]

How many miles are on it? I'm thinking it could be the O2 sensor has failed, could try unplugging it and see if it runs any better, don't leave it unplugged if you still have catalytic converter. Did you drain fuel and add new? Injector problem? No it is not normal to run like that. 32mpg sounds low but depending on your right wrist. Pull a spark plug out and take a look. There is a chance that the throttle position sensor is not set right but do not play with that yet.

[mgp steve]

Check the center coils. The originals failed at about 20,000 miles. Mfg date is last two digits in PN/SN stream. 09 and after should be good.

Easy check. With bike idling pull low tension lead from top of stick coil one at a time. If coil is good a 25 rpm drop should be had. If no change, pulled coil bad. If engine dies pulled coil good, opposite coil bad. Confirm by doing same procedure other side.

Remember, pull only the low tension wire. Don’t pull the coil off the plug and don’t pull the lower plug’s high tension lead.

Could be clogged fuel filter and/or leaking fuel pump hoses (internally).

[Joepi5]

Originally Posted by 908/930

How many miles are on it? I'm thinking it could be the O2 sensor has failed, could try unplugging it and see if it runs any better, don't leave it unplugged if you still have catalytic converter. Did you drain fuel and add new? Injector problem? No it is not normal to run like that. 32mpg sounds low but depending on your right wrist. Pull a spark plug out and take a look. There is a chance that the throttle position sensor is not set right but do not play with that yet.

Cat is still in. To my knowledge bike is completely 100% stock. I will try a short run with the O2 sensor unplugged, thanks for the advice!

[Joepi5]

Originally Posted by mgp steve

Check the center coils. The originals failed at about 20,000 miles. Mfg date is last two digits in PN/SN stream. 09 and after should be good.

Easy check. With bike idling pull low tension lead from top of stick coil one at a time. If coil is good a 25 rpm drop should be had. If no change, pulled coil bad. If engine dies pulled coil good, opposite coil bad. Confirm by doing same procedure other side.

Remember, pull only the low tension wire. Don’t pull the coil off the plug and don’t pull the lower plug’s high tension lead.

Could be clogged fuel filter and/or leaking fuel pump hoses (internally).

The main plugs that I changed out where pretty good. The secondary ones were black and a little wet, I will pull one of those back out and check them again.

How do I check the fuel fuel filter and hoses? Tank the tank off and pull them out?

Thanks for the advice!

[Joepi5]

Originally Posted by 908/930

How many miles are on it? I'm thinking it could be the O2 sensor has failed, could try unplugging it and see if it runs any better, don't leave it unplugged if you still have catalytic converter. Did you drain fuel and add new? Injector problem? No it is not normal to run like that. 32mpg sounds low but depending on your right wrist. Pull a spark plug out and take a look. There is a chance that the throttle position sensor is not set right but do not play with that yet.

The bike has around 40k mls on it. The fuel that's in there now is new, I didn't drain the old I added new and just went with it. After I emptied the first new tank I added injector cleaner with it. Ran a total of 3 full fuel tanks through it now.

The bike is to my knowledge 100% stock. I will go and unplug the O2 sensor and have a short ride to check.

Thanks for the advice!

[mgp steve]

The condition of the stick coil’s plugs is not a good indicator of stick coil operation. The lower plugs keep firing and keep the combustion chamber and center plugs clean(ish). The coil/rpm drop is necessary to determine coil condition. If the mfg. date is before ‘09 be ready to replace a currently serviceable coil soon. Checking its operation is easy: see photos.

Fuel tank removal is hard: see more photos.

A clogging fuel filter or leaking internal hoses will cause stuttering on acceleration and going uphill. To replace the fuel filter (and hoses) the tank must be removed. Left and right body work must come off. There are 14 machine screws attaching the L & R fairing to the frame. There are two fasteners that get overlooked (and therefore broken off) when removing the the L & R bodywork. They are directly behind the BMW emblems. They can be accessed from top or bottom. When lifting the fairing panels be ready to disconnect the turn signal connectors. Don’t forget to reconnect them on assembly.

The tank is aluminum and can be shorted to the positive battery terminal. Make sure the positive terminal is covered or the ground wire is disconnected. Two forward bird’s mouths rest on frame-mounted rubber biscuits. When the two hold down machine screws are removed, a 2 X 4 X 4 block can be inserted between the top of the battery and the pivoted-up tank. This will make the next few steps easier.

This era S may have plastic fuel disconnects on the right side, just above the right throttle body and hidden by the fairing. They are very brittle and will break. Don’t move them until you have a catch-pan ready for the fuel leak. They may have been upgraded to aftermarket steel, if so no breaking problem and no need for pan or pinching. There is a hard black plastic fuel pressure and divider manifold upstream of the TBs. The flexible fuel lines are connected to this manifold. DON’T pinch the plastic manifold-tubes!

The fuel pump power and low level light sender-wire connector is on right, inside, under the tank. Two machine screws attach the tank to the frame. One machine screw secures the air snorkel on the left side. This mates with a female receiver that is a threaded hole in the frame. Be careful on assembly not to strip it.

Once removed, drain the tank and lay it on its right side. Index all the flexible lines to their attach points. Colored zip ties work well and can be permanent indicators for the next disassembly. One hose will need to be disconnected in the tank to pull the assembly out of the tank.

The fuel pump assembly plate-to-tank, large o-ring seal is reusable. Factory swaged hose clamps are used throughout the plumbing system. Be careful when mechanically-expanding them. Prying from one side only can fracture brazes on the fuel pump plate assembly. Applying leverage with small awls on both sides, at the same time will uniformly expand the clamps. Replace with screw-type hose clamps. The hoses should always be replaced with new hoses regardless their condition because you don’t want to do this again anytime soon.

Check the stick coils first.

[Joepi5]

Originally Posted by mgp steve

The condition of the stick coil’s plugs is not a good indicator of stick coil operation. The lower plugs keep firing and keep the combustion chamber and center plugs clean(ish). The coil/rpm drop is necessary to determine coil condition. If the mfg. date is before ‘09 be ready to replace a currently serviceable coil soon. Checking its operation is easy: see photos.

Fuel tank removal is hard: see more photos.

A clogging fuel filter or leaking internal hoses will cause stuttering on acceleration and going uphill. To replace the fuel filter (and hoses) the tank must be removed. Left and right body work must come off. There are 14 machine screws attaching the L & R fairing to the frame. There are two fasteners that get overlooked (and therefore broken off) when removing the the L & R bodywork. They are directly behind the BMW emblems. They can be accessed from top or bottom. When lifting the fairing panels be ready to disconnect the turn signal connectors. Don’t forget to reconnect them on assembly.

The tank is aluminum and can be shorted to the positive battery terminal. Make sure the positive terminal is covered or the ground wire is disconnected. Two forward bird’s mouths rest on frame-mounted rubber biscuits. When the two hold down machine screws are removed, a 2 X 4 X 4 block can be inserted between the top of the battery and the pivoted-up tank. This will make the next few steps easier.

This era S may have plastic fuel disconnects on the right side, just above the right throttle body and hidden by the fairing. They are very brittle and will break. Don’t move them until you have a catch-pan ready for the fuel leak. They may have been upgraded to aftermarket steel, if so no breaking problem and no need for pan or pinching. There is a hard black plastic fuel pressure and divider manifold upstream of the TBs. The flexible fuel lines are connected to this manifold. DON’T pinch the plastic manifold-tubes!

The fuel pump power and low level light sender-wire connector is on right, inside, under the tank. Two machine screws attach the tank to the frame. One machine screw secures the air snorkel on the left side. This mates with a female receiver that is a threaded hole in the frame. Be careful on assembly not to strip it.

Once removed, drain the tank and lay it on its right side. Index all the flexible lines to their attach points. Colored zip ties work well and can be permanent indicators for the next disassembly. One hose will need to be disconnected in the tank to pull the assembly out of the tank.

The fuel pump assembly plate-to-tank, large o-ring seal is reusable. Factory swaged hose clamps are used throughout the plumbing system. Be careful when mechanically-expanding them. Prying from one side only can fracture brazes on the fuel pump plate assembly. Applying leverage with small awls on both sides, at the same time will uniformly expand the clamps. Replace with screw-type hose clamps. The hoses should always be replaced with new hoses regardless their condition because you don’t want to do this again anytime soon.

Check the stick coils first.

Great write up! Thank you very much. I have had the tank of already to bleed and service the ABS system, not more or less difficult than other bikes I worked on. But those plastic things that break, I have heard that before. But I did not find them the last time I had the tank off. Between which hoses or pipes are they?

I hope the screws that that secure the fuel pump to the tank will come loose as they are very corroded. Once in there the fuel filter will obviously be replaced as will the internal lines. Can I just use regular fuel hose for that? From the parts code of the fuel filter I noticed it's 8mm fuel hose, can you confirm?

Stick coils I will take a look at right away! Should the new ones be OEM or are there good aftermarket options?

[mgp steve]

I’ve only bought oem coils. Don’t know which version the knock offs copied. See old and new part # photo. I hope 853-01will be in the PN train. I went through eight coils in 80,000 miles. The 7th and 8th are the new part number and now have 140,000 miles on them. It’s worth buying oem.

Never have I seen the six screws corroded. The female holes are tapped straight into the aluminum tank. I’d soak the screws in penetrating oil for a few hours. Then, while tapping a breaker bar and Allen socket set up with a 16oz hammer, turn them 2° to 3° tight to shock and fracture corrosion. To be on the safe side, soak them again with penetrating oil.

I’d bite the bullet and buy oem hoses for inside the tank. Again, you don’t want to make multiple trips into the tank.

If your S is a BCR, they had no QD’s. If your bike had plastic QD’s they would have broken by now and a previous owner might have replaced them with straight hoses. If so, pinching works just fine but make sure not to reverse supply and return hoses. There are faint arrows showing direction of flow on the outside of the fuel plate near the hard tubes.

[Joepi5]

Coils are indeed of the old type on my bike. The coils on my F800 which was built in 2010 has coils made by Beru and are the originals. I suspect the Beru also makes the update R1x00 ones. I do agree OEM is better and will probably get those!

Aah I see now where the connectors are. I suspect they have been broken in the past as they are now directly on the solid tubes to the regulator. For now this is fine for me I marked them before I took them off the first time.

As for the hoses in the tank they will most definitely be OEM.

[Joepi5]

One more observation. I hooped up an OBD scanner with the motoscan app. And did a live parameter check on some parts. What are the normal well calibrated throttle valve angles?
I measure 1.83° closed and 86° fully opened. Shouldn't the fully opened be closer to the full 90°?

Edit;
The parameter I'm referring to is called DKP and the result is an angle in degrees. I'm guessing DKP stands for Drossel Klappen Position, but that seems logical to me.

[mgp steve]

Don’t think I ever knew throttle angle, I’ll check. I use a twin max for syncing. Very accurate. Has the witness paint on the TPS adjustment-screws been disturbed? I would think that the throttle plate should not be allowed to go to 90° or 0° as some “meat” needs to be left in to account for hysteresis. A quick search of the box of truth shows 5° at rest.

Are you reading ° mechanically or electrically?

You said the bike was operated in a corrosive environment. Have you shaken the TB-shafts at idle? You can do so by wiggling the bell cranks. Have a fire extinguisher for this test: direct propane onto any of the induction path to look for leaks.

Have you checked the pivot bearings?

[Joepi5]

Originally Posted by mgp steve

Don’t think I ever knew throttle angle, I’ll check. I use a twin max for syncing. Very accurate. Has the witness paint on the TPS adjustment-screws been disturbed? I would think that the throttle plate should not be allowed to go to 90° or 0° as some “meat” needs to be left in to account for hysteresis. A quick search of the box of truth shows 5° at rest.

Are you reading ° mechanically or electrically?

You said the bike was operated in a corrosive environment. Have you shaken the TB-shafts at idle? You can do so by wiggling the bell cranks. Have a fire extinguisher for this test: direct propane onto any of the induction path to look for leaks.

Have you checked the pivot bearings?

It's a readout of the motronic unit using the motoscan app (similar to a gs-911, but much cheaper and made to be used on a phone) so it's an electronic readout. Since I have no reference to the measured angles there is very little I can say about it.

The famous "blue paint" is very vaguely present on the tps mounting screws (maybe due to the slightly corrosive environment).The end stops or zero position I have not looked at yet.

Pivot bearings are smooth and without any play, if you mean the paralever bearings.

I have not checked the TB shafts. Initial throttle response is crisp and very good. I don't suspect anything mechanically wrong with the TB's.

First thing I will do is swap out some stick coils, a friend of mine has a R1150gs with good coils, I will ask him if I can borrow his for a test.

[Joepi5]

As for the corrosion, it's mostly the paint on the front of te engine that has been attacked, it's directly in the spray of road water. Other then that the subframe has rust on it.

[908/930]

Are you having fun yet? If you think it is ignition related also change the relay for the coils and check ground point for corrosion, my bike is older single spark so items slightly different. For the in tank hoses there is a non OEM option for way less, Beemerboneyard item Bbsubhosekit it is nylon corrugated tube intended for in tank use, also have external line BB161211800405ft. We're the spark plugs light in colour or dark?

When you use full throttle past 4000rpm would it pull smoothly to 7500rpm or was it misfiring?

[850dunstall]

neither of my 2 r1100s had the QD fuel line connectors, so i added them to both bikes. its usually the male end that failed. and they are much easier to disconnect than trying to pull the fuel line off the plastic ends leading to/from the pressure regulator.

[Joepi5]

Originally Posted by 908/930

Are you having fun yet? If you think it is ignition related also change the relay for the coils and check ground point for corrosion, my bike is older single spark so items slightly different. For the in tank hoses there is a non OEM option for way less, Beemerboneyard item Bbsubhosekit it is nylon corrugated tube intended for in tank use, also have external line BB161211800405ft. We're the spark plugs light in colour or dark?

When you use full throttle past 4000rpm would it pull smoothly to 7500rpm or was it misfiring?

Just got out of the shed. Tested the stick coils with a sparkplug that I got out of the bike last week (yes I do keep old spark plugs around, don't laugh...). One of the 2 stick coils caused no spark. I will give a ring to the nearest dealer tomorrow!

It was also misfiring at full throttle from 4000 to 7500 I think. It's was just less noticeable.

[Joepi5]

Originally Posted by 850dunstall

neither of my 2 r1100s had the QD fuel line connectors, so i added them to both bikes. its usually the male end that failed. and they are much easier to disconnect than trying to pull the fuel line off the plastic ends leading to/from the pressure regulator.

QD will be nice to have, I got doused in gas the first time I took the tank off. Do you have an example of which kind of QD will fit and work?

I'm based in Europe so I most likely won't find the exact same, but with some data sheet of info I would be able to find something.

I'm especially interested in what goes over the rigid tubes to the regulator.
Or just add a small piece of hose on it permanently and the QD on the other end?

Would something like attached work? Is there enough space for something like that? It seems quite cramped.

[908/930]

Hopefully you found the problem, easy fix. Yes I keep old plugs around also, better to have and not need it. To join the QD to the rigid tube I have about 50mm of flexible hose then the QD. Make sure the QD are dry break meaning they seal when removed I think there are some that don't seal. Pretty sure the ones I am using are manufactured by CPC and are chrome plated brass.