1999 R1100RT Rough Idle

1999 R1100RT 33,000 miles. I put in new spark plugs, set the valves, balanced the throttle bodies. Everything seems perfect except there is a rough idle and when accelerating through the range of RPMs while stationary there is an audible misfire everywhere in the range. Checked the fuel injectors and it appears that the right injector shoots more spray than the left. Running heavy on the concentrated techron for a couplele of gallons. No improvement yet. Lunging is present more than my 2000 R1100R. Could this be bad fuel injectors? Should there be a motronic adjustment to the throttle bodies? Not quite sure how to solve this problem. I also cleaned the brass adjusting screws in the throttle bodies. Really caked up with carbon. Cleaned the ports for the adjusting screws as well. I would also note that power at lower RPMs (3000- 3500) seems lower than it should be. Any further suggestions? I don't detect any play in the valve in the throttle body either.
Greg

Remembering from my '96 R1100RSL:

Are both throttle cables fully seated in the ferrules atop the throttle bodies?

Check that the sheaves around which the throttle cable(s) wind are free of any small rocks or other bits that would interfere with smooth cable seating.

dbrick said:

Remembering from my '96 R1100RSL:

Are both throttle cables fully seated in the ferrules atop the throttle bodies?

Check that the sheaves around which the throttle cable(s) wind are free of any small rocks or other bits that would interfere with smooth cable seating.

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Everything is seated and correctly adjusted, i.e., free play on the throttle cable.

Has your throttle position sensor (TPS) ever been messed with? Is the blue dot intact?

jsouth said:

Has your throttle position sensor (TPS) ever been messed with? Is the blue dot intact?

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The blue in still on the right side but the left side screw has no blue. I do believe both sides are marked when done so this has suspicion to me. I think I am down to TPS, Stick coils, Fuel injectors.

gnawit said:

The blue in still on the right side but the left side screw has no blue. I do believe both sides are marked when done so this has suspicion to me. I think I am down to TPS, Stick coils, Fuel injectors.

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There’s no stick coils on the 99 RT, the coil is a single unit just under the gas tank behind the steering stem.
Was this problem there before you did the tune up, or did it appear after the work was done?

Your answer above refers to the idle stop screws, and the question was about the set screw on the TPS on the side of the left throttle body.

m_stock10506 said:

There’s no stick coils on the 99 RT, the coil is a single unit just under the gas tank behind the steering stem.
Was this problem there before you did the tune up, or did it appear after the work was done?

Your answer above refers to the idle stop screws, and the question was about the set screw on the TPS on the side of the left throttle body.

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There were numerous problems before the tune-up.(I just purchased this.) The engine was hard to start. It was a rough idle and ran rough as well as lacked power. I knew I would have to go through the basics so I replaced spark plugs, replaced air filter, adjusted the valves, cleaned idle adjusting screws and ports. It runs a lot better except for the roughish idle and if i hold the throttle at any RPM, let's say 3500 I can hear it cough, or skip. It isn't a smooth RPM engine sound, but hiccups at any RPM. So, Roughish idle and the hiccuping when stationary. When driving it is pretty smooth except for the typical R1100 lunging.

Those aren't stick coils? Ok, I thought they were. I am talking about the allen head screws on the TPS on the left side throttle body. There are two screws that hold that in place. There are two slots where that TPS can adjust up and down. The screw on the right hand side of the TPS has blue paint. The screw on the left has no blue paint.
I let it get cold and started it. It ran pretty smoothly until it warmed up. Then the hiccuping started in.

Okay, I misunderstood. When you said right side, I heard right side of the bike. If you look at each throttle body you’ll see a screw that sets the idle stop. It is set at the factory and should still have a dot of blue paint indicating that they have not been moved. Generally, don’t move them.

What about the gas in the tank? Is the gas fresh? Are you sure there’s no water in there?

Injectors are very easy to slide out of their hold down, just be gentle when you handle the gas line at the end of the injectors. Remove them and point them into a container to catch the fuel. Run the starter briefly and check the spray pattern on each injector. After, check the gas that collected to see if any water settles out. If the injectors don’t have the same fine spray pattern, one or both may be clogged. You could try home cleaning, there are videos, or my preference is to send them to a professional injector cleaning service.

m_stock10506 said:

Okay, I misunderstood. When you said right side, I heard right side of the bike. If you look at each throttle body you’ll see a screw that sets the idle stop. It is set at the factory and should still have a dot of blue paint indicating that they have not been moved. Generally, don’t move them.

What about the gas in the tank? Is the gas fresh? Are you sure there’s no water in there?

Injectors are very easy to slide out of their hold down, just be gentle when you handle the gas line at the end of the injectors. Remove them and point them into a container to catch the fuel. Run the starter briefly and check the spray pattern on each injector. After, check the gas that collected to see if any water settles out. If the injectors don’t have the same fine spray pattern, one or both may be clogged. You could try home cleaning, there are videos, or my preference is to send them to a professional injector cleaning service.

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Here is the latest thing, which was in my last reply. On a cold start it idles and holds RPMs with no hiccuping, only the it reached operating temp does it do that. Any thoughts?

I had a similar problem with my 03 R1150R. I replaced both plug wires and cleaned the throttle bodies. Result was like a brand new bike.

burnbender said:

I had a similar problem with my 03 R1150R. I replaced both plug wires and cleaned the throttle bodies. Result was like a brand new bike.

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What on the throttle bodies did you clean? The idle set screw port, or the entire inside of the TB?

gnawit said:

What on the throttle bodies did you clean? The idle set screw port, or the entire inside of the TB?

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The idle bleed orifice is important. I would squirt Gumount into any opening I could find, followed by compressed air. I forget where they all are.

What Paul said.

Push, pull, bang blow. All four happen at different times in the same place.

Do a compression test to make sure that all four can happen in the same place and then find then find the missing link.

A compression test that is poor won't condemn your engine but you will avoid changing parts you don't need, or can afford.

dieselyoda said:

Push, pull, bang blow. All four happen at different times in the same place.

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I always thought that was suck - squeeze - bang - blow.

PGlaves said:

I always thought that was suck - squeeze - bang - blow.

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OK went through the entire process. I cleaned the idle adjusting screws and their ports. I cleaned the fuel injectors by wiping them down and spraying gum out through their ports. This small improvements in both the idle and performance while driving. I ran two tanks of fuel injector cleaner through and reset the throttle twisting it slowly three times with the key turned on. I checked the valve clearances that I had done two weeks ago and they were perfect. I rebalanced the TB's and ordered spark plug cables from local BMW. Replacing the cables made the biggest difference. After the cable were replace I rode the bike a bit and rebalanced the throttle bodies. WhenI picked up the spark plug cables I spoke to the BMW mechanic a bit. He told me to bring it by and he would take it for a ride to see what the trouble was. He drove it for maybe 7 minutes or so and when he came back he said it was a nice ride and it doesn't get any better that this. He has seen many worse but this was one of the better running RT's. I was happy about that. I guess there is always a bit of a roughness to the idle on these R1100RT bikes. My 2000 R1100R has a little bit of it but not as much as the RT. The specs are the same for both bikes so I guess the real difference is the computer system. I guess that is why John Gemi chips are so appreciated. thanks for the help gentlemen. I learned a good bit and I have a great bike. Two great bikes actually. Next up, modding the R1100R!

If you don't start with the basics, everything else you do will be pointless.

I have a stories about "mechanics" thinking they knew everything.

If you are happy, be happy but I can tell you my bike is as smooth as glass from idle to redline.

dieselyoda said:

If you don't start with the basics, everything else you do will be pointless.

I have a stories about "mechanics" thinking they knew everything.

If you are happy, be happy but I can tell you my bike is as smooth as glass from idle to redline.

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Did I miss something in my assessments? I did everything that should possibly have been done. Including new spark plugs, new air filter, cleaning out air box, torque the heads, injector test spray. It runs smoothly on the road yes, but the idle stutters a bit and there is the BMW surge aspect which doesn't bother me much. anything else I can do? thanks!

gnawit said:

Anything else I can do? thanks!

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Without me re-reading the entire thread, do you have an AF-XIED installed?

BC1100S said:

Without me re-reading the entire thread, do you have an AF-XIED installed?

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no i haven't.