Rough idling

[Steve H.]

Hi,everyone!

I got my GS-911(enthusiastic).Tested my Red Rudolf,showing 1 fault code-no exhaust flap.That is ok,scince Iremoved it.Engine idling rough 9(same way as before removing exhaust flap).There is a big difference in knock sensor values:Knock sensor 1:23.77V Knock sensor2:15.58V.There is a big difference in oxigen sensors values as vell.I have 6,000mls on bike.I don't push it hard.Only very rearly.Why it is idling rough???Any thoughts?Please help.

Thank You,Steve

[deilenberger]

I'm sort of a rough idle expert.. had it happen for a number of reasons - but here is what to check:

1. Valve adjustment. This is a base point before doing any other adjustments on the engine. Dunno what engine you have (would have to know the year of the bike), but on the earlier "hexhead" engines (up to '11) these are a simple screw adjustment. Details on doing it are available on several websites (including the DIY subforum for hexhead/camheads on the BMW-MOA forum.) The later "camhead" engines require adjusting with semi-sphere shims. Not hard to do, but you do need to replace parts to change the clearances, not just "adjust" things. Without a decent valve adjustment, all further work is pretty useless. Looking at your question - since you mention an exhaust flap - I'm guessing you have the camhead engine ('11 and newer).. so best you might be able to do is check that they are within specifications.

2. Gummed up idle steppers - unlikely with the miles on your bike. There is some grease on the screw thread of the stepper motor valve assembly. If it gets thick it can cause the steppers to fall out of sync, causing rough idle. To check this - use the calibrate O2 sensor function of the GS-911. LISTEN and FEEL the steppers as they perform the calibration (basically they go fully closed to determine their zero position then back to a normal run position - twice.) They should sound and feel the same. If one is markedly different then the other it's time to look at them.

3. O2 sensor output - set the GS-911 so it graphs the O2 sensor output. You can't really monitor them by watching the voltage as a number - you have to use the graph. Within 1 minute of cold start - both should start working, and they should look pretty much the same. They should have a switching interval of about 1-2 seconds, and be going full scale rich to lean. If one has fewer peaks or sits at a set voltage - it's bad.

This is how it should look:


4. Ignition coil - the coils can be subject to damage due to mishandling, and just because the service location is rather severe (hot..) Tests for this are: Disconnect the primary from one coil at a time. The coil which doesn't make a difference in the idle quality is bad OR test by substitution with known good coils. The two upper coils are identical. The bottom coils are a left and a right and are not identical. I've had one secondary coil (lower) that failed - and it's been replaced with a used one from Ebay. Unfortunately the current version of the GS911 software can't display cylinder misfires - I've talked with Stephen at HexCode about this and he's looking into if the BMS-K stores this info anywhere. Car ECU's do - it's an OBD-II requirement, but bikes aren't subject to OBD-II requirements, so it may not be stored.

So far when mine really got crappy - it's been #3. I've now replaced both. The first one failed fairly early on - around 30,000 miles or so, and I replaced it with a used one I'd snagged on ebay. The second one failed at around 60,000 miles, and at around 69,000 miles I finally spotted that was the idle problem, and I replaced it with a universal sensor from Denso. The original O2 sensors are NTK which is a division of NGK. The universal replacement requires splicing the wires with the kit they provide, but it's about 1/10th the cost of the OE one from BMW. It seems to work just fine (it's "Cylinder-1" in the plot above.)

I suspect the knock sensor difference is just due to the engine running in an imbalanced state, and once you smooth the idle out the sensors will have close to the same output.

When it's all working correctly the entire engine is remarkably smooth. Mine has almost no vibration through the handlebars, and the mirrors are clear throughout the RPM range... took a while to get it that way, but it's quite satisfying now when riding it.

Good luck!

[Steve H.]

Thank you Don for your time,and help!In the past I red alot of your posts,and learned a lot from you.
My bike is2012 R1200R running smoot at all RPMs.Only the fully warmed engine becomes rough in idling.Handle bar,tank,the whole bike just shaking.500mls ago I did valve cheks.Result is:at left cyl.0,180/0.180mm intakes;0.330/0.350exhaust
at right cyl.0.180/0.180intakes;0.350/0.350exhausts.At left cyl.exhausts,the difference is only0.02mm,witch is allmost nothing.Can not adjust that,scynce valve shims increments is0.05mm.
I did idle steppers calibration"relearned the ECUabouth steppers position".
O2 sensors(lambda sensors)graph-there is a big missmatch in diagramms!!
I did not check ignation coils yet.
I assume, the valve clearances are just in the mid tolerance(perfect).There is allmost no diference in valve lashes(messured on cold engine at room temperature).

Thank you Don for your respond and good will to help.
Steve H.

[David R]

Your difference in o2 sensors is the answer. It may or may not be the sensor. Vacuum leak? Bad stick coil? Bad o2 sensor? Isn't it under warranty?

David

[SF_Hooligan]

When it's all working correctly the entire engine is remarkably smooth. Mine has almost no vibration through the handlebars, and the mirrors are clear throughout the RPM range... took a while to get it that way, but it's quite satisfying now when riding it.

Wish mine was that smooth. I've just sort of accepted it being rather lumpy - sounds like I need to put some work in to figure it out. Thanks for all the good info!

[Steve H.]

Yes,David it could be anithing you mentioned.
My red beast is under waranty(2012).Going to go into dealers shop,but I like to know my bike, everithing abouth it.If it feels good, I am hapy.If there is a minor problem ie.rough idling-I am unhapy.I just simply LOVE my bike.2000+rpm,6th gear,tvist the trottle and I can feel dinamit in my backyard.It is a raket on two wheels.I Love my bike(my wife geting yelouos).

Thank you guys for your inputs and support!

Best regards, Steve H.

[roger l]

Don, do you have the part number for the universal oxygen sensor? My idle is getting pretty rough and I might try changing the oxygen sensors.

Thanks
Roger L

[deilenberger]

Don, do you have the part number for the universal oxygen sensor? My idle is getting pretty rough and I might try changing the oxygen sensors.

Thanks
Roger L

Have to look at my Amazon account.. have the info at home, but not at home now..

Hang on..

Found it.. Denso 234-4209 Oxygen Sensor

If you search it on Amazon, it's $29.00 - about 1/10th the cost of BMWs.

[Steve H.]

Hi everibody!
re.rough idling at 6000mls
I changed the two"main"spark plugs,left in two secondaries only regaped them to 0.8mm.The gap was 1.0mm.Checked the gap on new sparkplugs as well before installing them and set 0.8mm on them too.The idling become smooter.It diden't smootened out completelly.I assume got to wait to get broken in (consuming some oil still).Throttle respond is smooter and quicker.

Steve H.

[dbrick]

Don, do you have the part number for the universal oxygen sensor? My idle is getting pretty rough and I might try changing the oxygen sensors.

Thanks
Roger L

Have to look at my Amazon account.. have the info at home, but not at home now..

Hang on..

Found it.. Denso 234-4209 Oxygen Sensor

If you search it on Amazon, it's $29.00 - about 1/10th the cost of BMWs.

Interestingly, the "Does it fit your vehicle?" process on that Amazon page indicates that it does not fit the '07 R12R.

[deilenberger]

Don, do you have the part number for the universal oxygen sensor? My idle is getting pretty rough and I might try changing the oxygen sensors.

Thanks
Roger L

Have to look at my Amazon account.. have the info at home, but not at home now..

Hang on..

Found it.. Denso 234-4209 Oxygen Sensor

If you search it on Amazon, it's $29.00 - about 1/10th the cost of BMWs.

Interestingly, the "Does it fit your vehicle?" process on that Amazon page indicates that it does not fit the '07 R12R.

David,

Who you gonna believe? Me or Amazon?

It doesn't directly fit it since it must be spliced into the old connector. Electronically and physically it does fit and work fine with the R12R.