I have finally tired of welding and fire gumming the standard exhaust back together and found a reasonably priced end of line Remus system. Does anyone have any experience of fitting and using this system? Rather strangely the Remus agent insists that header pipe gaskets are not needed at the cylinder head; does that sound plausible? Other questions, do the OE panniers still fit, is any reprogramming of the Motronic system needed (or indeed possible) and is there any significant performance increase, with or without the above?

Thank you for any and all advice.

I recently purchased a '92 16v K100RS with a Remus exhaust.  Can't answer on the manifold gaskets or the Motronic reprogramming, but the panniers fit ok and the engine seems to run well.  Exhaust note is nice and not too loud. 

Previous owner purchased bike with Remus already installed.  I have been puzzled by the absence of the O2 sensor with the Remus on my bike.  Don't know if it never was there or was removed when the exhaust was installed.  If it was removed, I don't know what was done to allow for it not being there.  Maybe somebody else knows.

I have one on my Kafe project, and I used the 4 copper gasket rings at the head, but there was not much stud thread left on the studs,  if its designed to be used without them, then that would explain it.

Cheers.

I can't see it not requiring gaskets. If that were the case, both the exhaust flanges and the exhaust port faces would have to be ground in together to microsocopic tolerances to prevent leakages.

@KafeRacer wrote:I have one on my Kafe project, and I used the 4 copper gasket rings at the head, but there was not much stud thread left on the studs,  if its designed to be used without them, then that would explain it.

Cheers.

I was not thinking clearly when I wrote this, my headers are 2V BMW headers on a 4V head. My system is only remus from the collector rearward,  maybe what remus meant is you don't need anything between the headers and the collector, which is correct.

You do need a gasket on the header pipes at the cylinder head

The Remus headers, if that location IS what they're referring to, does use the four copper gaskets, BMW part number 11  62 7 662 083. I have that system on my '00 K1200RS and have sold a stack of their Revolution/Innovation systems over the years.

TWB, From your experience, what do you know about the Oxygen sensor that isn't used with the Remus exhaust?  How is the O2 signal used by the Motronic when the sensor isn't there?

What do I know about the oxygen sensor that isn't there? I'd say it's missing. Someone should search for it. But seriously, folks! It's not a must-use item and the system will simply default to full rich.



Remus headers for K100-16V (Motronic 2.1) K1100 (whether Motronic 2.1 or 2.2) and K1200 (Motronic 2.4) used a capped bung for the use (or non-use) of an O2 sensor. If any early Remus header was supplied without the threaded bung then it was meant for pre-Motronic bikes such as 8V K100 or for those not desiring to use the signal from an O2 sensor. The threaded bung hole has been in Remus production for fifteen-plus years.

As I said, the system will simply default to full rich, perhaps not a bad thing if performance improvements are expected, such as when removing catalysts, opening up airboxes/less restrictive air filters, and such.

Frank Stevens from BMW once told a group of the assembled, when queried yet again about the dreaded lean surging from Motronic 2.2 R1100 & Motronic 2.4 R1150 Oilheads in the early days, "You wanna get rid of the surge? Unplug the O2 sensor!"

So not having it is a good thing?!  Me likey...

However, if you want some adjustment range after removing the o2 sensor, there's always this handy article:

CO Potentiometre

Or this:

CO potentiometre UK

Oxygen sensors were only fitted to the post-94 k1100 engines. Prior to that mixture adjustment on the 16v engines was by using a small, multi-turn adjuster adjacent the fusebox.

Be gentle 'cos its very easy to turn the adjuster off the end of its travel. I use a watchmaker screwdriver to adjust mine.

Getting the mixture right makes a big difference to the fuel consumption (from 40 to 60mpg(imp) on a run).

@GerryP wrote:Oxygen sensors were only fitted to the post-94 k1100 engines.

Catalytic converters (and O₂ sensors) was available as an option on the 4V models from 05/91.

There are exceptions. No. American K100-16V & K1100RS used Motronic 2.1, with ignition amplifiers and oxy sensors partway into model year 1993. Then when Mo' 2.2 for K11 came along (7/93 as early MY '94) the amplifier disappeared. Motronic 2.1 in the US do not have even a plug for the fuel mixture dashpot in the wiring loom as 'Euro spec' bikes would have. BMW make accommodation for different markets.

I have three different engine looms in my garage for this Big Block K100/K12 hybrid I'm whacking together, as I sort out the myriad ways the fueling can be done.

@GerryP wrote:Oxygen sensors were only fitted to the post-94 k1100 engines. Prior to that mixture adjustment on the 16v engines was by using a small, muti-turn adjuster adjacent the fusebox.

Be gentle 'cos its very easy to turn the adjuster off the end of its travel. I use a watchmaker screwdriver to adjust mine.

Getting the mixture right makes a big difference to the fuel consumption (from 40 to 60mpg(imp) on a run).

I guess it depends on the requirements of the market, The '99 K1100LT I stripped to provide an engine for my sidecar did not have an oxygen sensor.  I stripped the bike completely, i would have noticed.

Al

Erk! I, er, sit corrected...  

So if I've got this right, Motronics 2.2 (o2+cat) could appear on any K1100 from 1991 onwards depending on the market and mood of the original purchaser.

And any K1100 which doesn't have an (o2+cat) will have Motronics 2.1 and should have the ineptly-named #13621461425 'idle regulating valve' that is used to set the overall mixture.

Both Motronic MA 2.1 and MA 2.2 equipped models was possible to get both with an w/o a catalytic converter.
Those w/o a cat have a pot meter to adjust the CO₂.

OK - excuse me while I bang my head against this computer for a minute.

That's better.

Thank you Inge. Does that mean I can install an o2 sensor on my Motronics 2.1 K1100?

@GerryP wrote:Does that mean I can install an o2 sensor on my Motronics 2.1 K1100?

No, it's a different Motronic MA 2.1 unit that is used with a cat than w/o.
Different internals and pin config. because of sensor vs. pot.meter.

Gerry if you don't stop banging your head you will hurt it. That's better now just accept that BMW does it "THEIR WAY"

Am somewhat confused by the above comments.  I just checked the Max BMW fiche for the 4V K100 and they show two different Motronic units(with and w/o Kat) and two different exhaust systems(with and w/o Catalytic converter) for the U.S. market.  It also shows an idle regulating valve without reference to exhaust configuration. 

Does this mean that the catalytic converter, and the O2 sensor which I cannot find on my bike were optional and my North American bike may have come from the factory without them?  If it was delivered without, is there an adjustment for fuel mixture?  I ask because when I bought it, the bike had colder NGK plugs installed and they were heavy with carbon deposits.  I wonder if this was done as tuning modifications for the Remus exhaust and I may have upset something when I installed the specified heat range plugs.  The bike is scheduled to be registered and put into service in a few weeks and I wonder if I need to plan on any fuel mixture adjustments.  If so, are these adjustments made with the idle regulating valve?

What's the VIN (last seven) of your K100-16V? I'll run it through The Great Computer and see what it might have come with from die Fabrik.

@GerryP wrote:Motronics 2.2 (o2+cat) could appear on any K1100 from 1991 onwards depending on the market and mood of the original purchaser...

Motronic 2.2 was released no earlier than production month 7 of '93 model K1100 in all markets, with or w/o catalyst. Prior to that month they were Motronic 2.1 with or w/o catalyst.

There will be an appropriate connector in the engine wiring loom (three wire rectangular) for the adjustable fuel pot, if so equipped.

@Two Wheels Better wrote:What's the VIN (last seven) of your K100-16V? I'll run it through The Great Computer and see what it might have come with from die Fabrik.

6494026

@Point-Seven-five wrote:

@Two Wheels Better wrote:What's the VIN (last seven) of your K100-16V? I'll run it through The Great Computer and see what it might have come with from die Fabrik.

6494026

Your Royal Blau (680) K100RS, built in 11/12 of 1991 came with factory Engine Spoiler in Silver (0566), Temp/Fuel Gauge (0721) and ABS (0524), and was sold as new by Heid's Hodaka in Johnsburg, New York on Friday, 21 August, 1992.

There were a stack of warranty claims performed such as the exhaust system cracking a total of three times, the first in Sept., '92, Aug., '95 and the last in late '97! The instruments failed, including the gear position indicator and speedometre reading inaccuracy on separate claims, the mirrors 'falling off', the gearbox 'porous', replacement of brake pads (dunno if that was front or rear but there were many complaints of fronts rattling), poor chrome on the exhaust pipes, slipstream air deflector breaking off, and a recall for the ignition switch bolts coming loose.

I reckon the original owner was quite fed up with having the very common exhaust fauilure multiple times and switched to a Remus system. Perhaps at that time the 02 was removed and certainly the Kat was as well. There should be a fuel pot somewhere on your bike to compensate - usually near the fuse/relay box. Check the part number of the ECU. If it has 13 61 1 464 649 then it was expected to have a catalyst, but if it's 13 61 1 464 649 then it has the correct ECU for non-catalyst.

The factory ETK which we access from BMWNA's Dealerspeed site suggests your bike was catalyst and 02 equipped from the factory. This might explain why the bike runs rich as; someone didn't figure on fuel adjustment requirements. Oxy and cats were new to bikes in those halcyon daze.

Oh, and the salesman made a $100 commission on the sale of your bike, and was wearing blue jeans instead of the de rigueur checked jacket and trousers.

.75, if your bike still have the same unit as when it did leave the factory and
was with a cat as TWB did say it would have the part # 13 61 1 464 607.
xx xx x xxx 649 is a later used part number....from 18/6-92 and on.

On the unit it would be marked with the last five digits w/o spaces 1464607.
It would also be a green Bosch label with the part # 0 261 200 270.

@Inge K. wrote:On the unit it would be marked with the last five digits w/o spaces 1464607.
It would also be a green Bosch label with the part # 0 261 200 270.

So is this the difference from the green to orange label.

@RicK G wrote: So is this the difference from the green to orange label.

If it has a orange or blue Bosch label, it's a non cat.

Thanks Inge that explains a lot.

TWB and Inge.  Thanks for the information!  That explains a few things I found on the bike when I restored it last winter.  Like the tag indicting Heid's Hodaka hidden on the rear mudguard under the rear cowl, and the tag indicating speedo replacement at 16,950 miles.  Also, the mirrors that fall off if you look hard at them.  All in all, the problems can't have been that bad as the bike now shows another 90k on the odometer, and still runs great despite being a little rich.

I am not at home right now, but will be checking numbers and looking for the mixture potentiometer this weekend.  

Again, thanks.  This place is great.

One more question comes to mind regarding the fuel mixture adjustment.

Is it correct to assume that I should adjust for a certain CO level on a CO tester.  Or is there another way, possibly with plug readings, although I would expect that to be pretty time consuming and probably not as accurate.

Your conclusions is correct (if the pot. meter is present on your bike).

Thanks, Inge.

My bike has the co adjustment pot. Should I expect to have to adjust this when I fit the Remus exhaust? What is the recommended CO% range?

The Remus is on, a relatively simple job. The sound is very ungentlemanly BMW at low speed but surprisingly little different to the stock unit at medium to high speeds. A short shakedown run has not revealed any perceptible performance change. If I can figure out how to add photographs I will.

The old possibly repairable exhaust is offered free to collector in UK:

https://www.k100-forum.com/t9929-k100rs-16v-repairable-exhaust-free-to-collector-in-uk

Revisiting this thread while slow at work today...

About a week ago I finally got the opportunity to get my K100RS4V out on the road and have put 250 miles on her since.  Performance is good and it runs strong up to 100mph where I back off to preserve my driver's license.

However, it has a barely noticeable overrich stumble/flatspot around 2000rpm in 1st and around 3-4000rpm(which could possibly be an ignition advance issue) when rolling on the throttle in all gears, and it runs hotter than my K75.  Haven't had a chance to take plug readings yet, but the exhaust has a fair amount of carbon buildup.

Checked fuel economy and am getting what appears to be around 44mpg (US gallons) with spirited riding.  Compared to my K75 this seems to be pretty good and the engine isn't using excessive fuel.

Must admit that I have yet to check the module numbers or the back side of the header for the O2 sensor spigot.  Will have to do that tomorrow when I pull the fairings off to see why the damn fan stopped working and let the engine puke the coolant.

Looks like she needs a complete tuneup.  Any links to a simplified ignition timing procedure that doesn't need a dial indicator stuck in the plug hole?  I have an inductive strobe light.

With the ignition timing I have always put the two cut aways so they match and give it about 2mm clockwise twist which is around 2.5° advance. I have on 3 occasoins checked this method using the dial gauge and it has been within 0.5° each time so that is all I do now. 3mm is 4° advance and it is astounding at just how much it improves the bottom end torque.

Just got home from work and checked the Motronic unit and and the O2 spigot on the header.

First, the Motronic has an orange label with the Bosch number 261 200 250 and a paper label with bar codes and the BMW(?) number 1 464 417.  This sounds like a non-catalyst Motronic, is that correct?

There is an approximate 3/4" hex head plug on the back side of the header about 6" ahead of the joint between the header and the Remus muffler.  I assume this is the port for an O2 sensor.  It is in a location where an installed sensor would probably interfere with the retracted side stand.

Ok, so it looks like the bike was converted to a non-catalyst configuration.  I guess that tomorrow I will have to see if I can find this mixture potentiometer. 

On a possibly related note, could the temperature sensor be bad, causing a rich mixture?  Yesterday, the bike overheated in traffic, puking out a fair quantity of coolant, but the fan and the idiot light did not come on.  My manual fan switch did not work either, while it worked the previous day.  Will need to check the fuses, sensor, wiring, and relay as the manual switch itself seems to be working properly.  Fan may be bad, had to repair the wire to one of the brushes last winter.

Rick, thanks for the ignition timing information.  Sounds like a fairly simple adjustment.  I like simple.

Can anyone comment on my fuel efficiency?  At 45 miles per US gallon it doesn't appear to be that I have an overly rich mixture.  That's the same as what my 75 gets.  And yet, the bike feels like the mixture is rich.

45mpg is not too bad and equates to around 52mpg for imperial gallons which is what I got from my 8v K100 but the K1100 gets a bit better at 56mpg which is more like your 16v K100. To get the 56-57mpg I need to be sitting on no more than 110kph which is 67-68mph but if I push it to 120kph then it does drop off a bit. I am a very heavy guy at 300lb and that makes a difference.

just an idea that someone suggested
was to use a timing light with built in advance control

then you could check the timing plate whilst running and dial up the advance manually to confirm the settings at the particular revs

there is a second timing mark (besides tdc ) on the rotor in the hall effects cavity, could be hard to see none the less ...unless highlighted with a white paint pen perhaps ?

RickG, Riding was a mix of twistys at 80-100kph and commuting at 110-130kph.  I weigh about 200lb so it sounds like the mixture is pretty close and not overly rich.  I guess it might be best to check the timing first. 

Charlie, are there any good photos of what I am looking for as far as timing marks?  Can't find any in my collection of service manuals.  When you say rotor, I assume you mean the "can" that rotates in the gaps of the Hall effect sensors.

That second timing mark, is it to set the advance?  Is there an rpm spec for it?  What does it align with? 

Weather is supposed to be rainy tomorrow so I think I will spend the day in the garage.

Is this the mixture adjust screw that replaces the function of the O2 sensor?

@Point-Seven-five wrote:
Is this the mixture adjust screw ?

Yes.