R 1150GS idling fast and getting faster

[DGB]

Hi all,
I'm looking for advice from 1150GS owners and those who may have come across this issue in the past.

My cousin's 2003 R 1150GS twin spark is giving him problems, the idle on the bike is erratic; the idle revs increase as it heats up, up to 1500-1800 revs shortly after startup. It is also running very rich.

A bit of background on the issue and how it has reared its head, please excuse the length of this pre-amble but I've included it for completeness and to identify potential causes.
Late last year the bike started slipping the clutch in 6th so with 73k miles on it it was decided to change the clutch - the first in his ownership of this bike since it had ~30k miles on it.
The clutch was changed by the usual mechanic who does work on the bike for him but it was noticed that someone had previously been at the gearbox/frame connection and they'd stripped the threads in the gearbox housing (the 100Nm bolt - I'm not sure what it is called) and it wasn't going to hold at correct torque.
Another gearbox was sourced and fitted and the bike was back up and running again. An issue arose with the gearbox slipping out of gears but that was adjusted at the gear linkage and resolved. This was the last of the work that the usual mechanic performed on the bike as he's had a change of work and his availability is very limited.

The next problem was that the bike seemed to intermittently stall slowing down to a stop. It wouldn't do it every time and it might not even do it at all when out for a couple of hours. The engine revs were in the normal idle range when this occurred.
The bike was booked into the local BMW dealer where a diagnostic was performed and they identified that a coil was faulty. The coil (one) was replaced but the stalling issue remained.
Another trip back to the dealer where they performed a throttle body sync and increased the idle revs to ~1500rpm (which IMO seemed to only mask the issue), no other issues were identified at the dealer. So, after shelling out €200 to the dealer the stalling issue still remained and the bike was idling at too high revs. And now, to add to the woe, there seemed to be a lag in response to opening the throttle - a drop in revs before it would pick up.
So my Dad decided to take a look at it - my Dad had a R1100 RT for a number of years and did his own work on that. Thinking that this was a possible fuelling issue, and doubting that the fuel filter had ever been changed, he changed out the fuel filter, cleaned out the tank, we found and freed up a pinched tank breather tube but the issue still remained.
We've since then checked and adjusted the TPS voltage, we've rebuilt the noisy throttle bodies, disconnected and reconnected the lambda sensor, we've plotted values from the GS-911 and compared it with a thread by Roger 04 RT with what a typical and it seems that the stalling issue is resolved.
My cousin took the bike for a spin and said it was great except that it was slightly less responsive than before and that the idle revs seems to be gradually increasing from the initial 1100 +/- 50 rpm up to 1500-1700 rpm only a few minutes after a cold start. We've checked the idle actuator and it didn't seem to make any difference so we pulled out the bowden box, cleaned it out and silicone lubed the cables and up at the idle actuator. This has restored the function of the idle actuator but still the revs are erratic. Just today we've re-balanced the throttle bodies but still the problem remains.

My cousin has put a bit of money into the bike of late and he's frustrated that it's not working right for him. He's not willing to put much more money into it as he did that on a previous bike and ended up spending too much on it and eventually traded it.

If anyone has any suggestions on potential causes or solutions I'd like to hear them - a half gallon of petrol and a match has already crossed our minds.

Thanks in advance,
DGB

 

[Roger 04 RT]

It sounds like your adjustment sequence or cable tension may be wrong. Below is a draft of something I'm working on. Compare it to your sequence.
RB

DRAFT
Although most everyone in this forum has a good procedure for synchronizing their bike’s throttle bodies, I recently reviewed the full BMW Repair Manual procedure and noted some details that I hadn’t seen in the past. The main problem with the BMW procedure is that it’s written for someone with a BMW test station. Below is the procedure, directly from the manual but with edits for clarity and to replace BMW specific and outdated terminology (e.g. choke and carburetor). There are also some Ed. Notes that I’ve added with practical clarifications.

BMW R1150RT Repair Manual
Procedure 13 60 110
Checking throttle-cable play, checking and adjusting idle speed and throttle-valve synchronization

- Notes and Attention (in red) from BMW Repair Manual
- Ed. Notes and other edits by me for clarity--e.g. Choke changed to Fast Idle Lever, Carburetor changed to Throttle Body
- Headings (e.g. STEP 1, …) by me for clarity​

STEP 1: Preparation
- Test-drive the motorcycle until the engine is warm.
- Remove the left side panel.
- Remove the right side panel.

(Ed. Note: BMW Manual indicates remove small access panel in fairing but mine is glued in)​

Oil temperature: ..................at least 90 C (194 F)

Ed. Note: At the Handlebars
- Push back rubber caps on throttle and fast-idle cables.
- Use the adjusting screws to increase the play of throttle and fast-idle cables.

(Ed. Note: Two turns will create about 1 mm.)​

Fast Idle cable free travel: ........................................approx. 1 mm (0.0393 in)
Throttle cable free travel: ........................................approx. 1 mm (0.0393 in)​

Ed. Note: At the Throttle Bodies
- Turn the adjusting screws to increase the play of the cables for the left and right throttle valves.

Throttle valve cable free travel: ....................................... approx. 2 mm (0.0787 in)

(Ed. Note: Two turns of the TB adjuster is about 2 mm.)​

STEP 2: Adjust Idle Speed and Left/Right Idle Syncronization
- Connect hoses of your throttle-body vacuum-synchronization tool (e.g. Twin Max, Harmonizer) to the vacuum ports on the left and right throttle bodies.
- Start the engine.

! Attention: Do not allow the engine to idle for longer than is necessary, because the trim panels near the exhaust could be damaged.

(Ed. Note: Use a fan to move air past cylinder heads and oil cooler.)​

- Adjust idle speed by turning the air bypass screws while checking that the throttle bodies are balanced.

Idle speed: ........................................ 1,100 ±50 rpm

(Ed. Note: A hot idle speed above 1100 rpm, results in leaner AFR readings during cold-starting, this based on data from GS-911 logs from several R1150R/GS/RTs.​

Note: Make sure that both throttle valves are closed.

(Ed. Note: firmly resting on the throttle stop screws)​

! Attention: Do not tamper with the sealed stop screws of the throttle valves, as otherwise the idle-speed volume flow will have to be reset by the manufacturer.


STEP 3: Remove Free Play from Throttle Body Cables
- Carefully turn the adjusting screw of the left throttle valve and reduce play until the reading of the vacuum synchronization tool changes.
- Turn the adjusting screw very slightly in the opposite direction until the reading returns to its original value.
- Tighten the locknut to secure.

Note: Make sure that the reading does not change when you tighten the locknut. Adjust throttle cable play at throttle valve so that no play is perceptible, but the throttle valve reliably contacts the stop screw (no strain on cable).

- Adjust the right throttle valve in the same way.

Note: Zero play can cause the throttle valves to rattle.

(Ed. Notes:
-One quarter to one half turn of the TB adjuster results in 0.25 to 0.5 mm slack.
-Considering this warning, and the instructions above to "adjust so that no play is perceptible" if the throttle cable adjusters on the throttle bodies require adjustment, either the left or right (as appropriate) should be turned clockwise, so as to not remove the "imperceptible play”.
-The BMW procedure says to use engine rpm or engine vacuum-balance to indicate when the throttle cables are fully tensioned and have started to move. A much more sensitive indication can be had by monitoring the TPS voltage between pins 1 & 4. When the voltage starts to increase, the throttle is moving. This will work for the left TB, Fast Idle Lever and Throttle Twistgrip.)​

STEP 4: Adjust Throttle and Fast Idle Lever Free Play
- At the right handlebar, use the adjusting screw to adjust play of the throttle cable.

Play of throttle cable: .....................................approx. 0.5 mm (0.0197 in)

(Ed. Note: One turn of the adjuster is about 0.5 mm.)​

-Push the rubber cap into position over the adjusting screw.

(Ed. Note: Remember to secure the locknut.)​

- At the left handlebar, use the adjusting screw to adjust play of the fast-idle cable to zero.
- Push the rubber cap into position over the adjusting screw.

(Ed. Notes:
-Remember to secure the locknut.)
-This results in the throttle-valves being opened about 4 degrees and results in a TPS voltage of about 1000 mV in the mid-detent position. Based on many R1150 GS-911 logs, most Fast Idle Levers are not adjusted this tightly. It is quite common to see as little as 0.96-1.28 degrees of throttle advance with the Fast Idle Lever set. This may explain many cold-starting problems.​

- Move the handlebars all the way from left to right and check the settings. Make sure that engine speed does not vary when the handlebars are moved in this way.

STEP 5: Check and Adjust Left/Right Synchronization at Off-Idle Throttle Positions
- Repeatedly open the throttle gradually and increase engine speed from idle to approximately 2,500 rpm to check throttle-valve synchronization. (Readings shown by synchronization tool must increase and decrease together). If necessary, correct by turning the adjusting screws of the throttle-valve cables at the throttle body.

(Ed. Notes:
-As mentioned above, either the left or right adjuster should only be turned clockwise, otherwise the adjuster will be over tensioned and play will be reduced to zero.
-Determine which adjuster to turn clockwise as follows: if the vacuum-balance tool shows more vacuum toward the left throttle body, turn clockwise the right TB adjuster. Likewise, if the vacuum-balance is toward the right TB, turn the left TB adjuster clockwise.
-When you tighten the locknut, the TB cable will be tensioned a slight bit more, anticipate this by slightly under-adjusting the tension.)​

Note: Make sure that when the throttle grip is released both throttle valves return to their fully closed positions.


STEP 6: Completion/u]
- Tighten the locknuts and recheck throttle body balance.
- Seal off the vacuum bores or reconnect charcoal canister purge hoses.
- Reinstall Left/Right Fairings, assembly is the reverse of the disassembly procedure.

(Ed. Note: I love that phrase, “assembly is the reverse of the disassembly procedure.”)​

 

[DGB]

Wow, thanks for the comprehensive response Roger.
What you've said about the number of turns of adjusters on cable and the length of free play that this equates to leads me to think that we haven't given enough slack in the cables on the throttle bodies even though they are on their stops and they are balanced. In step 5 we've been doing that slightly differently which may result in even less cable free play.

We'll go through what you've suggested above and see if there is any improvement.

Thanks for your help,
DGB

 

[mspenz]

How did this go?
Roger spotted a loose TPS stop screw on my GSA from over 3000 miles away

Might also be worth getting a can of WD40 with a jet and carefully spray around all the TB hose clips and connections one at a time with the engine running at 'idle' just in case that there is a leaky intake allowing too much air in, if the engine speed increases when you spray a particular area then there's likely to be a poor connection and air ingress causing increased rpm.

Roger, I totally agree with your comments regarding slow cold start speeds due to the fast idle lever being incorrectly adjusted. I noticed a huge difference in play on my bike especially after performing the 0=250 reset and the lever basically made no difference, I now have it adjusted so that the bike starts and idles at around 1100rpm cold but this quickly increases to around 1600rpm as the engine warms, similar to your problem DGBs !
I never let the bike idle and just ride off and usually close the idle lever after around 500mtrs, at 1km when I stop at a junction my idle is at 1000rpm but increases to about 1200rpm when hot (I prefer a slightly higher tickover) but it does fluctuate a little....it is a boxer twin after all

Hope you get sorted.

Mike.

 

[Steptoe]

H
The clutch was changed by the usual mechanic who does work on the bike for him but it was noticed that someone had previously been at the gearbox/frame connection and they'd stripped the threads in the gearbox housing (the 100Nm bolt - I'm not sure what it is called) and it wasn't going to hold at correct torque.
Another gearbox was sourced and fitted and the bike was back up and running again. An issue arose with the gearbox slipping out of gears but that was adjusted at the gear linkage and resolved. This was the last of the work that the usual mechanic performed on the bike as he's had a change of work and his availability is very limited.

Ohh dear.......

I hope that is the last work he performed on the bike..... The gearbox/frame connection threads you mention aren't actually in the gearbox. It's simply a short section of threaded tube held in place by two small bolts that needed replacing, at a cost of £5 for a used item that simply slides back in place between the gearbox lugs.
So you bought another gearbox that you didn't need..


Seeing as it seems he didn't know what he was doing i'd check he hasn't fecked anything else up while he did the work before you go down the route of reading the american constitution .

 

[Roger 04 RT]

...

Seeing as it seems he didn't know what he was doing i'd check he hasn't fecked anything else up while he did the work before you go down the route of reading the american constitution .

Given the number of fecked up gs-911 logs that get sent to me for analysis, many need the Constitution (TB Sync) and Bill of Rights (z=250 mV). But I'm sure you've seen 100X the botch-ups that I have.

 

[Johny w]

Ohh dear.......

I hope that is the last work he performed on the bike..... The gearbox/frame connection threads you mention aren't actually in the gearbox. It's simply a short section of threaded tube held in place by two small bolts that needed replacing, at a cost of £5 for a used item that simply slides back in place between the gearbox lugs.
So you bought another gearbox that you didn't need..


Seeing as it seems he didn't know what he was doing i'd check he hasn't fecked anything else up while he did the work before you go down the route of reading the american constitution .

Thanks for highlighting the threaded bar issue, I removed my hepco and becker crash bars when I first bought my bike, and the top bolts on the footrest holder didn't feel good at all. I havnt replaced the bolts but imbworried about them and was thinking .aye a helicopter insert.
But it sounds like you are referring to the same bolts/threaded bar.......is the bar easily replaced?
Thanks

 

[theoneandonly]

FFS just realised this is a 10 year old thread , and the OP hasn't been here for 18 months ....did he sort it ?

 

[Hay Ewe]

Me too, its annold thread.
Broken wires in the throttle cable from the twist grip to the bowden box can also do some funky things, like increase the revs, stick throttle, high idle.....

 

[Neil W]

Thanks for highlighting the threaded bar issue, I removed my hepco and becker crash bars when I first bought my bike, and the top bolts on the footrest holder didn't feel good at all. I havnt replaced the bolts but imbworried about them and was thinking .aye a helicopter insert.
But it sounds like you are referring to the same bolts/threaded bar.......is the bar easily replaced?
Thanks

As long as the two retaining bolts in the gearbox casing aren't siezed and then do not snap