Found the reason for my intermittent crappy idle..

[dirtrider]

Morning Don

 

OK I see you are already unplugging your sensors from the side I was talking about. If you look closely you should see where the sensor plug will unplug from the other side of that long black plastic piece leaving the long black plastic piece disconnected from either end. I usually unplug at the (rear) short plug on the sensor as that is easy to do with the black connector still attached to the coil cover.

 

 

That probably also isn’t your problem as the long black plastic piece was probably replaced with the new sensor.

 

[ragtoplvr]

years ago when connectors were not as good as they are now i had wonderful results with this stuff

 

http://www.stabilant.com/

 

I had a car that always took spells of running crappy, all you had to to fix is unplug harness to distributor and reconnect. Also fixed some Zilog development systems that would fail weekly and need cards reseated. this stuff works

 

rod

[Don_Eilenberger]

Rod - agreed, wonderful stuff. I believe if you go back about 6-7 posts you'll see where I used it.. Expensive, but worth it.

[Don_Eilenberger]

Morning Don

 

OK I see you are already unplugging your sensors from the side I was talking about. If you look closely you should see where the sensor plug will unplug from the other side of that long black plastic piece leaving the long black plastic piece disconnected from either end. I usually unplug at the (rear) short plug on the sensor as that is easy to do with the black connector still attached to the coil cover.

 

 

That probably also isn’t your problem as the long black plastic piece was probably replaced with the new sensor.

Yup - it was.. but I wasn't even aware that the long black piece could be removed from the O2 sensor.. (My bionic eyes are 15/20, except within 18".. and reading glasses are OK, but not a substitute for my nearsightedness that I used to have - my old right eye had a focus distance of about 2", was wonderful for close examination of stuff.. not so wonderful for anything else.. butttt - I digress..) I'll have to take a look with my magnifier..

[Don_Eilenberger]

Just a quick update..

 

The idle again deteriorated.. this time the sensor on cylinder #1 (starboard side) was failing. Could see it's response with the GS911 real-time plotting function. It was switching slow, and the voltage was decreased. It would come to life at higher RPMs, again a sign of a failing sensor (greater exhaust velocity past the tip..)

 

Decided on a new replacement for it - found a Denso 4-wire on Amazon, listed as a universal replacement (including for several BMW cars.) Came with a nice splicing kit to attach the factory connector to it. (Denso part 234-4209) Overnight shipping via Amazon + the sensor cost was still less then buying it at any of the local auto parts stores. I ordered it at 7PM Friday, 10AM Saturday it was at my door.

 

Did the splicing. Installed it. It's now idling fine again and the slight surge I had at low RPM is now gone again. This failure was somewhere around 65,000 miles (but I waited until 70,000 just because I hadn't gotten around to it, was too busy riding the thing.)

 

The GS911 comes through again.

 

For those who don't want to do the splicing, EuroMotoelectrics has the same Denso with the factory connector on it: http://www.euromotoelectrics.com/ProductDetails.asp?ProductCode=O2-E452 for $89 (vs BMW's $240 price.)

[lawnchairboy]

Prolly need to sticky that on the parts list, thanks!

 

[Guest Kakugo]

Glad you found out the issue...

 

I have been looking into it and the NTK parts number for the R1200RT (K26) is OZA630-BM1. Just an alternative to the OE and Denso parts. I've been using NTK O2 sensors in my cars for years and they are excellent quality.

[Don_Eilenberger]

Actually - I believe that's the same NTK sensor as comes on the bike.. which are the ones I've had fail. I'm hoping the Denso lasts at least for a few years. Interestingly - the Denso says it's "Assembled in USA from Foreign Components".. guess that's for the percent US content numbers for car manufacturers.

 

The switching ones all provide the same basic output, the only difference I can imagine might be the longevity and the heater current. In watching my bike from startup cold - the Denso takes about 5-10 seconds longer to go "on-line" then the NTK one in cylinder #2. I might imagine that's a difference in the heater. It isn't anything that would concern me.