I guess this is mostly aimed at Motorcycle Mike as I know he's done this, but advice welcomed from all quarters. Why do I want to do this? Because I'm an inveterate fiddler. Apart from the Motronic unit itself, what else would I need (wiring loom isn't a problem)? There's a K1100 unit on ebay.uk ATM that I'm watching. Would the K1100 unit be suitable?

Not sure about the UK but all US K1100s have a cat and corresponding O2 sensor in the exhaust. I don't know enough about cats to know if that would be an issue or not though.

I think the water temp sensor is different but that should be easy to deal with.

The k1100s don't have a mass airflow unit but do have an air temp sensor.

I remember Inge saying that there are two motronic units one for the cat and one for the CO2 adjustment and they had different coloured labels.
Personally I would say the cat is the way to go but considering Europe got the same models as Australia there wont be many around with cats.

The threads on the water temperature sensor are different so you'll need a K11 'spigot' (at the front of the engine, top, left hand side) and a different radiator hose due to the bend. I'm using later (10/93 on) Motronic 2.2 with an oxy sensor but no catalyst, no dramas, on my hybrid. There are three different Motronic 2.1 brains: with and w/o catalyst & with catalyst and O2 sensor, as well as the rarer manual C0 adjustment, and two later Motronic 2.2 as they all had cats and O2 sensors by then but there are two part numbers, plus their supersessions.

I reckon it can be done with a bit of time and access to the part variations.

worth investigating at least dai

I also had a thought about that recently and think I could get by with a minor loom I recon ...whatever goes to the motronic  in addition to the standard k100 loom ...just splice the bits in and rewrap ?
 k1100 throttle bodies for the tps on the end .as the k100 coupling is just slightly different ..plus the injector minor loom ,

hmm what else is there ?

brakes, instruments and lighting could stay the same ?

more thoughts required ?

I would like to use the moronic on the K75s but seeing as the ignition is intergral with the ECU its a bit difficult.
Olaf was saying in another thread that the Volvo 300 series ECU had the same basch part number as the K100 L Jet so a thought occured (a rare thing these days) that maybe there is somewhere a six cylinder moronic that might be adaptable.
Food for thought.

yeah I guess rick

the injector and coil timings should mate up well with the k75 ....not sure about the hall effect position - timing though  but a bit of research ...or a car in a wreckers could help with the details ?

I'm already running K1100 throttlebodies so I do have the relevant TPS (somewhere).

TWB: I don't understand why I'd need to change the temperature sensor. Does the Motronic one have a different curve? As I understand what you're saying, a late 2.2 with oxy sensor would be the one to go for, but I'd need to weld a sensor mounting point into the exhaust system. Into an exhaust pipe or into the silencer where it would get an overall view of the exhaust gases?

I was originally thinking of 'converting' Brick 2 but circumstances dictate that it and the Bandit will be up for sale as soon as Brick 2 is finished. I want that Falcone. However, once the Falcone arrives LFB will be available for fiddling with, so it also won't stop me doing some preparation.

The temp sensor has only one sensor  and the K100 sensor will give double the resistance that is required.
It works from one pin to the other not 2 sensors to ground in the same housing.

Thanks Rick.

Can anyone identify the version of this, supposedly off a 1999 K1100LT:

http://www.ebay.co.uk/itm/272289355102?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I asked Motorworks but for the first time ever the numbers on the label had them beat.

Working out what that last number is was the trick... its a nine.

According to realoem 1361 7651599 (2.2) was used from 08/98 to 04/99 on K1100LT authorities model without catalytic converter and is fully suppressed.

THANK YOU!!!!! If you'll pardon the pun, I hadn't figured that last digit to be a nine. Okay, seems like I need to bid on it.

Charlie - both LFB and Brick2 have custom looms on where the FICU and ICU sub-looms are completely seperate from the main loom. That, in theory, gives me the option of returning to the AFM setup with minimum fuss if it all goes TITSUP (Totally Incapable To Support Usual Performance).

Kaptain has it right, with the additional info that it superseded from a number that streches back through '95 (1 464 811). I'd say the eBay offering is the one to use, and inexpensive too! Drill a hole and weld in a bung for an O2 sensor and you'll be laughing.

Two Wheels Better wrote:Drill a hole and weld in a bung for an O2 sensor and you'll be laughing.

Drill the hole where? Exhaust no.1 would be the easy option but does it need to be in the silencer to read all of the gas flow?

On my Big Block I used Kiwi Malcolm's collector. That's where we drilled and welded the bung, so it gets all four pot's exhaust fumes to sniff on. Does it need all four? My guess is that it's a better reading of the temperature, but how scientific do we need to be?

As that Motronic unit on Ebay is for non cat models a O2 sensor isn't used.
But you gonna need the pot meter which is on non cat models for adjusting the CO.

I have the 'pot', Dai, if you need it, no charge. I'm not gunna use it. Lemme know. Look on that harness for the connector. The US looms didn't have it.

Thanks guys. It looks like this project will be a 'go' if I get the unit. I've put a reasonably high bid on it and I'm quite willing to go to about half of what Motorworks want for a secondhand one.

I love fiddling.

Hi Dai that seller is very close to you so might be worth collecting if successful. He breaks a lot of ex police bikes. I have bought a few things from him.

If your 2.2 project fails I have several 2.1 units and you can have one if you want.

that's an amazing price dai

what do you think that it will get ? 

far too many good bits ...and bikes over there to drool over with amazingly cheap prices

charlie99 wrote:that's an amazing price dai

what do you think that it will get ? 

far too many good bits ...and bikes over there to drool over with amazingly cheap prices

I've no idea. The auction expires next Tuesday and unless an item is genuinely super-rare, mid-week early-afternoon auctions tend to go for (relatively) low prices.

Ringfad wrote:that seller is very close to you so might be worth collecting if successful. He breaks a lot of ex police bikes. I have bought a few things from him.

If your 2.2 project fails I have several 2.1 units and you can have one if you want.

I'll definately keep that in mind! Craigavon is a bit out of my way in that it means crossing a lot of urban jungle, so I'll pay the postage if I win it. Useful info that he breaks police bikes though.

I got the unit for £22.65 inc P&P. TWB - I think I have a CO adjuster somewhere from when I stripped a K100LT wiring loom for parts. It fits under the relay box, IIRC? I'll get back to you if I can't find it.

It mounts to the hold-down plate for the battery from a K1, K100RS4V or 93- K1100.

Thanks Duck. That explains why it was held on with two self-tappers - not very BMW-like.

Hi Dai,
Sorry for the late reply, I've been over to Spa with the Flying Brick.
I've got both 2.2 and 2.1 Motronic sets but I'm on a 2.1 off a K100 16v. Don't worry about TPS as they fit it to everything  http://www.realoem.com/bmw/enUS/part?id=0526-EUR-06-1996-89V2-BMW-K_1100_LT_0526,_0536_&mg=13&sg=54&diagId=13_0522&q=13631461852

I'm going to try the 2.2 set to my K as I have an intermittent cut out issue coming back off a closed throttle for a long time e.g going round a long hairpin on a track. I've tried all the earths and cleaned all plugs but no change so I'm going for a swap.

Temp sensor is different on the 16v 11 & 12's so you'll need to swap that over.
http://www.realoem.com/bmw/enUS/part?id=0526-EUR-06-1996-89V2-BMW-K_1100_LT_0526,_0536_&mg=17&sg=12&diagId=17_0629&q=12611341602

One thing I must mention. The fuelling is not right for an 8v engine. I had my bike on a dyno last year and it was all over the place. I originally fitted the 2.1 to allow a BMW map specialist to remap to suit but when it came to it he didn't want to take it on-thanks mate!

If you look on the partial graph below from my dyno run you'll see that the fuelling is all over the place and should sit between the red upper and green lower limit lines-it clearly doesn't. Unless you can get someone with an eprom reader and a dyno, you're stuck. If you find someone let us all know!



I've got a breathed on 1100 this year so I'm back in the game.

Good luck.

I've just found this list for the K100 16v and is seems that all 16v water temp sensors from 100 to last 1100 are compatible-even some cars.

http://www.realoem.com/bmw/enUS/part?id=0523-EUR-03-1991-89V1-BMW-K_100_RS_0523,0533_&mg=17&sg=12&diagId=17_0628&q=13622242184

Motorbike Mike wrote:
.......
I'm going to try the 2.2 set to my K as I have an intermittent cut out issue coming back off a closed throttle for a long time e.g going round a long hairpin on a track. I've tried all the earths and cleaned all plugs but no change so I'm going for a swap.
.......

Mike, I had same problem a couple of years back which was resolved. Three of my exhaust valves were way too tight which meant they were not closing completely. Roll the throttle off and clutch in, and the engine would die. My wildly eratic fuel consumption would equate to your eratic dyno results
Read a summary and the solution in this post

I still think that my problems are electrical. Once the motor is dead it won't come back off the throttle, I have to kill the system with the kill switch and it will run again. Different ECU's and batteries make no improvement so the search continues.
Thanks for the tip anyway.

Ah - good! I was a bit disappointed when Mike explained the fueling problem but better to know before I started throwing parts all round the garage rather than afterwards.

Just to add to a comment earlier on this thread. It isn’t entirely necessary to switch to 1100 TBs, I have recently seen someone stick with the K100s and mount a 16v TPS to a slotted backing plate to gain the required TPS orientation.