BMW K bikes (Bricks)


You are not connected. Please login or register

Go to page : 1, 2, 3  Next

View previous topic View next topic Go down  Message [Page 1 of 3]


1Back to top Go down    Things that BMW put there to annoy me on Sun Mar 28, 2010 7:09 am

Ned

avatar
Life time member
Life time member
Dear Brick Pilots;

According to me there are a few things that BMW have installed in our bricks which give us a reasonable amount of annoyance. I am sure that there was a good reason for it but as our bikes get older it can be argues that we can simply do without them.

In my case (1986 L-Jetronic fuel injection) the two that come to mind are:

  1. the TPS switch, and
  2. vacuum modification of fuel pressure regulation.
The TPS switch: I think, is a perfectly useless thing on our bikes (L-Jet systems). It consists of two microswitches which tell the injectors to turn off/on when coasting or to enrich the fuel mixture at full throttle.

I have an issue with the turn the injectors off function. I can only imagine that it was put there to save fuel and some think that it even stops backfire.

I've found that by disconnecting it the bike is much smoother to ride in tricky and twisty conditions. I was amazed by the transformation. The TPS switches the injectors on and off making the bike lurch back and forth especially in tight corners and places where revs hover around 2000rpm. I am even happy to say
that all that jerking back and forth add to wear and tear of splines. Someone said once that BMW test riders would disconnect them in slippery conditions like snow... I can understand that.

Check it out by simply unplugging the thing... it will not hurt the bike.

Vacuum line to the fuel pressure regulator: Again, is a part of a standard L-Jetronic system. On my bike it is next to useless. I find that my girl is very happy to run at a very steady fuel pressure you get by disconnecting the vacuum line from the throttle body. It starts easier, runs smoother and has more power
on tap. Yep, the pressure is about 10% higher than with the vacuum disconnected, but it is rock steady and this translates to a smooth running bike. I think that K1100

Again, check it for your self by disconnecting the vacuum line (don't forget to plug the throttle body vacuum port) and ride at around for a bit. It won't hurt anything but it may improve things for you.

    

2Back to top Go down    Re: Things that BMW put there to annoy me on Sun Mar 28, 2010 6:59 pm

Crazy Frog

avatar
admin
admin
Ned,

I understand your frustration with these 2 devices.

The only purpose of the TPS is to avoid burning fuel when you are decelerating and want the engine to quickly rev down (to 2000rpm).
Why burning fuel when you want to stop or quickly slow down? Unless you shut down the throttle, the switch doesn't have any effect. The engine break on the K100 is powerful because of the TPS.

By altering the way that the fuel regulator works, you also modify the parameters to the EFI. There is no electrical connection between the regulator and the EFI. The EFI only assume that you have the correct fuel pressure. The way that the EFI calculate the amount of gas required by the engine and to command the injectors is only a time factor. The only variable on the injector is how long they open. They are working ON & OFF. If you need 1cc of fuel per cycle, the computer will assume that at a pressure of X PSI, it will take x ms to deliver this amount. I was also wondering why the pressure regulator is tied to the vacuum. After spending a lot of time studying the EFI, this is what I deducted. I may be wrong too. Is this explanation sounds right?


__________________________________________________
1986 k75, 1985 K100rt, 1985 K100rt/EML sidecar.
    

3Back to top Go down    Re: Things that BMW put there to annoy me on Sun Mar 28, 2010 8:04 pm

Ned

avatar
Life time member
Life time member
[quote="Crazy Frog"]Ned,

I understand your frustration with these 2 devices.

The only purpose of the TPS is to avoid burning fuel when you are decelerating and want the engine to quickly rev down (to 2000rpm).
... The engine break on the K100 is powerful because of the TPS.

Hi Bert,

Before we turn everyone off with a technical discussion on L-Jet let me tell you that from a practical point of view... pulling a plug on TPS is a good thing if you spend a lot of time shifting gears in suburbs and on twisty roads. In the case of a constant cruise at speed, none of this makes any sense because the TPS is not used by the system. The fact that the bike runs better, in my opinion, without it is proof that it is just an add-on.

I've found that the only way I can smooth the ride out with the TPS is to back off and apply a the rear brake or the clutch as motor goes into an off state. It is almost like turning the ignition off on every slow corner.

Turning the fuel off is a good thing, in principle, but in practice it is a simple on/off action with an appropriate jerk which you may not want at the time, like in the middle of a tight roundabout or a wet road. I get a better result by doing it my self by using the throttle.

This may be my bike, or my riding style, but since I've disconnected the thing (many months ago), I have not had a single backfire. With the TPS connected, it was a common occurrence. BTW my fuel consumption hasn't chaned at all.

By altering the way that the fuel regulator works, you also modify the parameters to the EFI.

Yes, but not strictly true. The electronics logic does not change as it has no input to tell it anything. I simply:
  • change fuel pressure by 10%. This puts 10% more fuel into the cylinders, nothing more.
    • by removing the vacuum fluctuations (pretty wild at idle) we regulate the fuel pressure and this amount of fuel into the cylinders precisely


There is no electrical connection between the regulator and the EFI. The EFI only assume that you have the correct fuel pressure.
Precisely. One can "jet the carbs" on L-Jetronics by simply changing the fuel pressure Smile.

The way that the EFI calculate the amount of gas required by the engine and to command the injectors is only a time factor. The only variable on the injector is how long they open. They are working ON & OFF.

Yes, and the duration is the only thing used to turn on the taps and measure fuel. So the more pressure the more fuel and vice versa. One wonders why they use the coarse vacuum to play with it since we are talking about approx 10% difference between high and low pressure setting. I notice that they got rid of it all with the Monotonic systems.

If you need 1cc of fuel per cycle, the computer will assume that at a pressure of X PSI, it will take x ms to deliver this amount. I was also wondering why the pressure regulator is tied to the vacuum. After spending a lot of time studying the EFI, this is what I deducted. I may be wrong too. Is this explanation sounds right? Laughing

Sounds good. I see it as a way of leaning/enriching the mixture by +/-10% according to the load as measured by the vacuum. I think that they finally give up using vacuum because it is so erratic. A simple experiment anyone can do is to simply disconnect and take it for a ride (don't forget to close the vacuum port first). Smile

    

4Back to top Go down    Re: Things that BMW put there to annoy me on Mon Mar 29, 2010 3:02 am

K-BIKE


Life time member
Life time member
HI Ned,
Really interesting, what do the plugs look like after a good bit of use with the engine configured as you have it, I would be most interested to know.
Regards,
K-BIKE

    

5Back to top Go down    Re: Things that BMW put there to annoy me on Mon Mar 29, 2010 4:53 am

Ned

avatar
Life time member
Life time member
@K-BIKE wrote:HI Ned,
Really interesting, what do the plugs look like after a good bit of use with the engine configured as you have it, I would be most interested to know.
Regards,
K-BIKE

Good point. I will check. I expect the mixture to be a bit richer, but do not expect anything drastic.

I am seriously thinking about investing in a adjustable fuel pressure regulator so that I can dial up whatever the value works the best i.e. somewhere between 36 psi and 42 psi.

However, I've had the TPS off line for many months without any effects on fuel consumption. I am happy with the way the bike runs without it.

    

6Back to top Go down    Re: Things that BMW put there to annoy me on Mon Mar 29, 2010 5:49 am

phil_mars


Life time member
Life time member
I think it is a case of if it works for you then all is well and good. Personally I have no issue with the TPS whatsoever and really appreciate the engine braking it provides and have absolutely no problem with a jerky throttle reaction as it has such a long rotation and smooth action.
Quite the opposite observation on a new Honda I took for a test run which had a very quick acting throttle in comparison and difficult to get used to as it felt like it was either on or off.
As for the vacuum driven fuel pressure regulator probably a different story and worth further testing.

Regards,

Phil

    

7Back to top Go down    Re: Things that BMW put there to annoy me on Mon Mar 29, 2010 5:58 am

Ajays

avatar
Life time member
Life time member
Well folks,
That is the most interesting post I have read for a longtime...my only comment is, I certainly get a backfire, maybe our climate compared to yours has this effect.
When I collected my last K75s I rode it back 87 miles at 60/70's and I got a few backfires. On inspection when I arrived home I noticed the TPS was disconnected, probably because his commuting to work daily and experiencing the non smoothness in traffic. I reconnected it set it and no more backfires.
Best suck it and see.
Ajays


__________________________________________________


AJAYS
    

8Back to top Go down    Re: Things that BMW put there to annoy me on Fri Apr 02, 2010 10:23 am

Ned

avatar
Life time member
Life time member
Dear Brick Pilots,

Today I did my usual 100km ride just to have a couple beers in my favourite pub, yes we will drink even on on Easter Friday Smile. The first 50km was with the TPS off.
She was smooth as usual, although running a bit colder because our temperatures at the moment are approx 25 or so.
On the way back I decided to reconnect the TPS just to see if I exaggerated the difference.

Well, I hated it ... backing off, accelerating, slower corners, even gear changes were jerky and unsettling. i did not enjoy that at all, so TPS is off again.

This may be just me or my setup. My TPS is adjusted so the it switched on as soon as I touch the throttle. I think that this is correct.

Now, am I just a TPS hater or is it that something is not correct with my system? So, I wonder if some kind soul would take their steed out and do a run with and without the TPS and let me know if the ride feel as dramatically different as my is? I suggest a slow suburban ride with lots of gear changes with the TPS plug off to start with.

    

9Back to top Go down    BRILLIANT!!! on Fri Apr 02, 2010 5:20 pm

scottiesharpe

avatar
Silver member
Silver member
as the gents at guinness beer say, "BRILLIANT!"

I had never thought of disconnecting the TPS. I always had it in my mind that the TPS sensor was like on the Motronic systems - a potentiometer position sensor. I never realized it was only a switch.

I just disconnected it and went for a short drive to get some lunch..... the jerking is GONE at low speeds. Just great!! This weekend I will try the FPR disconnect idea.

Thanks!


__________________________________________________

Scottie Sharpe
1987 K100RT
    

10Back to top Go down    Re: Things that BMW put there to annoy me on Fri Apr 02, 2010 7:53 pm

Ned

avatar
Life time member
Life time member
Thanks Scottie, I am glad that you were able to do the experiment. I am also happy that you concluded the same thing as I did.

I word of caution for the people with Motronic systems: DO NOT disconnect your TPS ... the bike will not work.

A bit of history. I've cleaned my injectors, replaced all the intake rubber components and tried to balanced the throttle bodies. It fixed the buzz and vibrations at 3000-4000rpm, but I coudn't get rid of the on/off jerking at slow speeds. I finally concluded that the TPS may be at fault, so I experimented and concluded that because it is a fuel saving device I can do without it. Thus the experiment.

Now for the FPR ... I have a pressure gauge in line so I can diagnose even the smallest change in pressure behavior and correlate it to what is happening at the time.

In my setup, I know that :

  • the FPR does not hold the pressure (leaky one-way valve), but it holds at 36-38psi nicely (new one on order).
  • the pump works well, but the by-pass valve is dicky... the pressure can get above 100psi if I test the output pressure without the regulator.
  • took one plug out (after 50km) as per request (K-Bike?) and found the colour to be fine, just a touch of sooty gray. Maybe a touch on the rich side but no buildup of carbon. Will do it again after a few tanks of fuel (premium only).
Despite all of that the bike runs just fine without the vacuum control. I even give it a few squirts to almost the redline and found no hesitation.

Anyway Scottie, if possible can you report on the fuel pressure with and without vacuum... I know that this may not be possible.

My test setup... I can read the gauge as I ride:

    

11Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 1:54 am

K-BIKE


Life time member
Life time member
Excellent Work Ned,
Well done on smoothing out the vibrations as well. Interesting that the plugs look good, one benefit of the old leaded fuel was it made reading plugs easier as the lead deposits used to get a fine range of colour change to show up on them.
Regards,
K-BIKE

    

12Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 4:14 am

Ajays

avatar
Life time member
Life time member
Hi you Gurus,
I notice you all live in comfortable climates. I would love to see a report back on this from a Guru in colder abodes.
My bikes run without problems except a slight vibration at 60mph on the K100's. So in my case, if it aint broke don't mend it.

Ajays


__________________________________________________


AJAYS
    

13Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 5:16 am

Ned

avatar
Life time member
Life time member
@Ajays wrote:Hi you Gurus,
I notice you all live in comfortable climates. I would love to see a report back on this from a Guru in colder abodes.
My bikes run without problems except a slight vibration at 60mph on the K100's. So in my case, if it aint broke don't mend it.

Ajays

Hi Ajays,

I would normally agree with you, but here there is nothing that points to cold/hot weather performance.
The TPS switch simply saves fuel and stops backfires, and the vacuum control of fuel pressure has to do with enriching the mix under acceleration etc.

The EFI controller has absolutely no knowledge of these two parameters being changed. I think that Bosch did this to simplify the fuel injection electronics.

My major thing is with the TPS however. It may be technically/environmentally a nice thing to do but is makes the bike a pig to ride at low speeds.

The vacuum thing? well, I think that it all works better without it. I think that BMW agrees... there was a vacuum switch connected to the EFI controller once... it was removed... anyone know why?

Motronic system ignores the vacuum altogether. Obviously they have found better ways of doing things. Oh yes, they got rid of the TPS as well and replaced it with a proper potentiometer.

Yes, it is not broken, but it can be improved Smile

This is not a a disclaimer, but if you have any doubts at all, don't try it.

    

14Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 7:20 am

phil_mars


Life time member
Life time member
I don't really want to weigh into this discussion too much as I mentioned before if it works for you well and good but it does raise some interesting issues that may be related to the year of the bike in question.

My bike is an '84 model and definitely not in pristine condition but it is certainly no "pig" at slow speed. I have two "toy runs" and quite a long ride at about 20km/h with a flat front tyre to prove just how well it does run at slow speed.

Mine still has the original throttle cable and definitely has a lot more rotational movement than I was used to on other bikes, real bm's included. Very Happy
I suspect the newer models may have a quicker action throttle to "improve" things and thereby creating additional problems.

Based on what I have read the Jetronic system has been used on a lot of vehicles and was merely adapted for the K100 and I think all used the TPS until the Motronic came along which essentially is a refinement as the Jetronic was a refinement over mechanical fuel injection.

If I had the ability to "improve" mine at all it would have carbs back on it in a flash as, other than the way it starts, performs no better than any bike I have ridden and I could really do without the added complexity of 26 year old electronics.

As for the vacuum switch, it was tied to an advance in the ignition curve and it was discovered it had no real effect and was discontinued.

Regards,

Phil

    

15Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 7:55 am

Ajays

avatar
Life time member
Life time member
With the old Amal carbs, on an early morning ride on a cold misty morning, the performance of the engine and the crackle of the exhaust certainly told you the engine was happy...now on a normal hot days it was not so enjoyable.
Enviroment certainly made a difference then Ned.
Just tried it with both my K75s with the plug off...both backfired on shut down. I have yet to try the K100's
To each his own matey.
Ajays.


__________________________________________________


AJAYS
    

16Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 9:22 am

Ned

avatar
Life time member
Life time member
The reason I asked for input on this is that I was never happy with the way the girl performed at low speed. I remember talking about this on the old forum.

Being a tinkerer and a bit of a perfectionist I just had to fix it, but not having a point of reference I've hoped that someone can duplicate my results. I just had to confirm that I don't have a component/setup problem and Scottie did just that.

Also, I am not really interested in the backfire, I just want to get rid of that on/off problem which has to do with the injectors switching on/off. my bike does not backfire at all and I know that the injectors do not leak, so my setup is working well.

Phil: Mine still has the original throttle cable and definitely has a lot more rotational movement than I was used to on other bikes, real bm's included...

Phil, I don't think that the throttle is very quick. Maybe i will try to get the TPS adjusted even closer to the fully closed than I have now. I think that I am running out of adjustment, however.

Phil: Based on what I have read the Jetronic system has been used on a lot of
vehicles and was merely adapted for the K100 and I think all used the
TPS...

Yes, there is a lot written about early Euro cars which used Jetronic in many guises. BMW changed nothing other than omit the Auxiliary air valve. Now lets look at it this way ... the bike weighs 260kg and the car ... probably 1000kg. I'll bet that the momentum of the car at speed would take care of any slop in the system. Not so on the bike.

Phil: If I had the ability to "improve" mine at all it would have carbs back on it in a flash as...
I remember arguing this before Smile ... from my point of view dual Webers with small filters would look great... replacing all the empty plastic boxes would be good.

Ajays: Just tried it with both my K75s with the plug off...both backfired on shut down. I have yet to try the K100's To each his own matey.
Thank you for trying ... did you feel any difference in behavior on the road, ie is it any smoother on slow corners etc?

    

17Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 03, 2010 11:12 pm

K-BIKE


Life time member
Life time member
Totally off the subject, I reckon the kangaroo that Ned has in his picture is a distinguished aristocrat of a kangaroo, it is all in the look on the face.
Regards,
K-BIKE

    

18Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 2:40 am

phil_mars


Life time member
Life time member
"TS
A throttle switch with dual contacts is provided to inform the ECU of idle position, deceleration, cruising and full-load (WOT)
conditions.
Voltage at nbv is applied to TS terminal 18 from the system relay under cranking or running conditions. The TS earth path is
made through the ECU via terminals 2 and 3.
When the engine is at idle the idle contact (terminal number 2) is closed and the full-load contact (terminal number 3) is open. As
the throttle is moved to the fully open position, the full-load contact closes and the idle contact becomes open. Under cruising
conditions with a part-open throttle, both contacts are open.

Fuel pressure regulator
The pressure regulator is fitted on the outlet side of the fuel rail and maintains an even pressure of 2.5 bar in the fuel rail. The
pressure regulator consists of two chambers separated by a diaphragm. The upper chamber contains a spring which exerts
pressure upon the lower chamber and closes off the outlet diaphragm. Pressurised fuel flows into the lower chamber and this
exerts pressure upon the diaphragm. Once the pressure exceeds 2.5 bar, the outlet diaphragm is opened and excess fuel flows
back to the fuel tank via a return line.
A vacuum hose connects the upper chamber to the inlet manifold so that variations in inlet manifold pressure will not affect the
amount of fuel injected. This means that the pressure in the rail is always at a constant pressure above the pressure in the inlet
manifold. The quantity of injected fuel thus depends solely on injector opening time, as determined by the ECU, and not on a
variable fuel pressure.
At idle speed with the vacuum pipe disconnected, or with the engine stopped and the pump running, or at WOT the system fuel
pressure will be approximately 2.5 bar. At idle speed (vacuum pipe connected), the fuel pressure will be approximately 0.5 bar
under the system pressure.

Idle speed adjustment
A by-pass valve is provided that connects the inlet manifold to atmosphere. This allows a metered volume of air to by-pass the
throttle and the valve may be adjusted to increase or reduce the idle speed"

These are excerpts gleaned from somewhere giving a description of part of the LE jetronic system and it is specific to the LE but not necessarily the vehicle fitted.

Ned if your experience had been a "one-off" then it could have indicated further investigation required. The fact that you got collaboration straight away suggests otherwise unless of course two bikes on opposite sides of the planet have the same fault.
As for the TPS or TS as described above the adjustment is in the manual and is pretty clear cut and once set as described should not require further movement. So all I can say if you have checked everything, and it seems as if you have, then use what works and see who else has the same result.
In my case it works fine so is staying put. In Ajays case disconnecting it causes backfires which is what it is supposed to happen so who knows?

Regards,

Phil

    

19Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 4:36 am

Ned

avatar
Life time member
Life time member
@K-BIKE wrote:Totally off the subject, I reckon the kangaroo that Ned has in his picture is a distinguished aristocrat of a kangaroo, it is all in the look on the face.
Regards,
K-BIKE

He is a magnificent beast. I don't know if you ever stood in front of one, but I can tell you that he is as tall and as impressive as he looks. Majestic, belligerent and oozes testosterone Smile Smile

    

20Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 4:53 am

Ajays

avatar
Life time member
Life time member
Ok Ned enough about yourself,
Probably true. but what about the Roo..!
Ajays


__________________________________________________


AJAYS
    

21Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 6:16 am

Ned

avatar
Life time member
Life time member
Ok, lets sum up the TS function:

Two micro-switches, three possible states:

  1. idle switch on, throttle closed, injectors off, deceleration at maximum
  2. full throttle on, injectors get extra fuel
  3. both switches off = normal cruise speed (or plug disconnected).

Lets look at it this way:

  1. we are cruising and close the throttle to slow down. The injectors are off and no fuel is used.
  2. the rpm = 2500 and we are about to accelerate again, but the fuel is off
  3. open the throttle slightly... the first that happens is that the fuel is switched on again and the amount injected is dependent on the air intake etc. ...what we get is a squirt of fuel and the bike accelerates forward.

All of the above is fine, but:

  • when we backed off the transmission would have slowed and the gearbox and splines would take the load of braking, the rider lurches forward.
  • when we open the throttle the bike will accelerate and the trans/splines will take the load of acceleration after the slack is taken up.
The end results is that we will feel the full effect of the transmission/splines slack in a jerking action of declaration and acceleration, I called it the on/off state and I find this off-putting at slow speeds.

For example, I tend to keep my revs around 3000+ and use gears to maintain the speed and revs, so the on/off thing is a pest. When the TPS is disconnected the injectors are never fully switched off, so the transition is more gradual and controllable.

The fuel pressure thing... well that will need a video to show... will do one soon.

Finally, Scottie and I have the same opinion... OK it is possible that we need to adjust the TPS so that it switches off the fuel injectors closer to fully closed butterfly position if possible. I may try this tomorrow. In fact, I would be happy to adjust out the effects of the idle micro-switch, but keep the full throttle one in play for obvious reasons.

    

22Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 6:20 am

Ned

avatar
Life time member
Life time member
@Ajays wrote:Ok Ned enough about yourself,
Probably true. but what about the Roo..!
Ajays
Hi, my thoughts were that my roo kind of reflected most of us, but was too chicken to say so. Now that you mention it, I accept your assessment SmileSmile

However,let me push your button a bit: going for ride tomorrow... clear sky 25C and the beach pub is waiting Smile

    

23Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 7:23 am

Ajays

avatar
Life time member
Life time member
Psst Your cruel streak is showing again.
I too am off to a bike meeting today in the local town of Baldock...I shall have a pint also....temp now 48f....patchy blue with the threat of rain. View it on U-Tube by typing in Search. "MrFantavox".

As for the TPS...you have got it. Set it low before the click and you will enjoy the other functions.

Good write up as usual Ned.
Ajays.


__________________________________________________


AJAYS
    

24Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 04, 2010 5:29 pm

K-BIKE


Life time member
Life time member
The sun is shining and I shall also go for a ride it is 8.30 and the temperature is very pleasant, going to be a nice warm day.

I have to say I am not sorry we don't have wild kangaroos here as they are a real problem if you hit one especially the big reds. I feel the same about the American hooved rats (deer) which infest the road verges in many States, on the various lists I belong to many list members have hit them in cars and on bikes.

Keep up the good work Ned it is most interesting.
Regards,
K-Bike

    

25Back to top Go down    TPS and a pillion on Thu Jan 17, 2013 9:14 pm

rosskko

avatar
VIP
VIP
I am going to open up this old thread as it is the best discussion of the subject I could find.

My TPS is giving me all kinds of grief when I stick my daughter on the back. She is constantly being thrown backward and forward as I negotiate the start stop city traffic.

The TPS is being disconnected this afternoon to see what difference it makes. Fingers crossed for a lot.

rossco


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ05/1988

K1100RS 0194321
    

26Back to top Go down    Re: Things that BMW put there to annoy me on Thu Jan 17, 2013 9:56 pm

krambo

avatar
Life time member
Life time member
I disconnected my TPS some time ago and have yet to discover any real reason to re-connect it. It makes for a much smoother ride without it Wink

P.S. I haven't noticed any real difference in fuel economy


__________________________________________________
1984 BMW K100RT, 1993 BMW K1100LTIC,1982 Kawasaki KZ1100 Spectre
"Aut viam inveniam aut faciam."
http://www.its-personal.net
    

27Back to top Go down    Re: Things that BMW put there to annoy me on Thu Jan 17, 2013 10:57 pm

Ned

avatar
Life time member
Life time member
same here. The bike is smooth and much nicer to ride. No difference wrt fuel consumption.


__________________________________________________
I reserve the right to voice my opinions on any subject known to man
Ned

05/1986 (K55) K100RS Motorsport (Europe), Production Code: 0503, 110k km, VIN:0140519 (SOLD)
1976 Honda Goldwing GL1000 (naked)
1997 BMW K1200RS red, VIN: WB10544A1VZA22667
    

28Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 12:56 am

charlie99

avatar
VIP
VIP
rossco ... a much better solution is to adjust the tps so that it never hits the (closed position ) micro switch ...

that way you still have the "wot " (wide open throttle ) switch in place

just undo the screws a little and turn it anti clockwise ...just a bit till you hear the microswitch release .....whilst still throttle closed



just a heads up



Last edited by charlie99 on Fri Jan 18, 2013 4:36 am; edited 1 time in total


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

29Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 12:58 am

Halo

avatar
Life time member
Life time member
here here Charlie


__________________________________________________
84 K100RS 0014803
93 FZR1000 EXUP
    

30Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 1:07 am

rosskko

avatar
VIP
VIP
Oh. That sounds equally as easy.
Thanks.
Now as Ned says, when the temp drops below 30 I will go for a ride. Maybe he didn't say it in this post but I did see it mentioned. And beer.


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ05/1988

K1100RS 0194321
    

31Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 1:10 am

charlie99

avatar
VIP
VIP
mmmmm beer is a plan .

knocking off early today ....warmish for up here too .

hope it cools down for all you southerners

holds a stubby up ...for when it cools down and you get home .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

32Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 1:15 am

Ned

avatar
Life time member
Life time member
rossco wrote:Oh. That sounds equally as easy.
Thanks.
Now as Ned says, when the temp drops below 30 I will go for a ride. Maybe he didn't say it in this post but I did see it mentioned. And beer.

Just for the record, my TPS is adjusted just as Charlie suggested.

I'll settle for mid 30s ... a cold beer or two and a cigar is the go I reckon Smile


__________________________________________________
I reserve the right to voice my opinions on any subject known to man
Ned

05/1986 (K55) K100RS Motorsport (Europe), Production Code: 0503, 110k km, VIN:0140519 (SOLD)
1976 Honda Goldwing GL1000 (naked)
1997 BMW K1200RS red, VIN: WB10544A1VZA22667
    

33Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 1:16 am

klompy the grey brick

avatar
VIP
VIP
what suburb...its explosive out here.....in the west...


__________________________________________________
KKlompy
1984 K100RS Silver VIN 0019026 Mitt eine Staintune Zorst.
1997 K1100LT Dark Grey VIN WB1052600W0237453.

Chassis number0019026
Vehicle code0503
SeriesK589
ModelK 100 RS 83 (0502 ( 0503 )
Body typeK 100 RS 83 (0502
Catalog modelECE
Production date1984 / 07
Engine0513)




    

34Back to top Go down    Hi on Fri Jan 18, 2013 2:41 am

scottiesharpe

avatar
Silver member
Silver member
My tips is still disconnected from when we discussed this a couple of years ago. Been about 10k miles or so. Still lovin the smooth throttle. Don't miss the jerking.

Haven't had a chance to fiddle with the fpr.

I have a rattle at medium speeds like chain guides are gone. Yuk. I don't really want to take it apart. I think I'll just keep driving it as is as see what happens. I love the bike, but I'm at 130k now and the cosmetics are getting rough. sick

See ya!

Scottie


__________________________________________________

Scottie Sharpe
1987 K100RT
    

35Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 4:34 am

Halo

avatar
Life time member
Life time member
Backed mine off cheers guys will try tommorrow
Good one Rossco for bringing this thread back to life


__________________________________________________
84 K100RS 0014803
93 FZR1000 EXUP
    

36Back to top Go down    Re: Things that BMW put there to annoy me on Fri Jan 18, 2013 5:16 am

rosskko

avatar
VIP
VIP
Just backed mine off also. The temp is still over 30 and a storm is brewing so I guess I will have to wait also.


__________________________________________________
1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ05/1988

K1100RS 0194321
    

37Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 8:03 am

andyb

avatar
Gold member
Gold member
Hi all, came across this thread and gave disconnecting the TPS a go today (on my way to test ride a K1200LT - is that bad??). Huge difference, much smoother in stop start conditions, and seems to change from 1st to 2nd much smoother as the engine doesnt die back as much............performs like any 'normal' bike again. I'm wondering whether connecting all four vaccum outlets to the FPR line would make any differnce also? Am I right in thinking that the K1100 throttle bodies have them all connected this way?


__________________________________________________
AndyB
'03 K1200GT,

'88 K100 RT
Chassis number: 0097248 ; Vehicle code: 0504; Series: K589
Model: K100RT 84 (0504 (0505) Body Type: K100RT 84 (0504)
Catalog Model: ECE; Engine: (0504); Production: 1988/9
    

38Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 8:19 am

charlie99

avatar
VIP
VIP
andy the k1100 is a verry different beast .... well in some ways at least ...with a different type of engine management and throttle body setup ( even has vacuume lines at the rear of the throttle boddies )

just use the back off principal on the tps on 8v k100 ....and if it suits ...well thats good

dont think there is any advantage to connecting up the vacume lines at all ...as it is just a port ...with verry little flow capabilities ....but could be an issue in the future, tracking down all the possibilities of added hose and connections to the vacuume chain if a leak develops .

good luck mate


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

39Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 8:27 am

RicK G

avatar
VIP
VIP
The K1100 doesn't have the vacuum on the FPR but they are connected together at the back of the TBs but it only has any effect when the throttle butterflys are open a bit. It is there mainly to make positive ventilation for the crankcase.
I wouldn't say there could be anything gained from connecting all the vacuum lines together. I have the back 2 connected together but only to supply vacuum for the cruise control.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

40Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 8:35 am

andyb

avatar
Gold member
Gold member
Thanks Charlie & Rick, I'll leave it how it is!
cheers


__________________________________________________
AndyB
'03 K1200GT,

'88 K100 RT
Chassis number: 0097248 ; Vehicle code: 0504; Series: K589
Model: K100RT 84 (0504 (0505) Body Type: K100RT 84 (0504)
Catalog Model: ECE; Engine: (0504); Production: 1988/9
    

41Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 12:01 pm

Comberjohn

avatar
Life time member
Life time member
Hmmm.
Yes, remember this thread from before and it is interesting. Think I'll give your method a try, Charlie.
Haven't been aware of any particular issues with jerkiness but after riding K's for a few years you adapt without being aware.
Anyone think the transmission jerkiness may have contributed to the premature demise of some of the 6 rivet drive shafts?
Maybe BMW didn't factor that in to their original design.
Could be worth tweaking the TPS for that reason alone if you have an early 6 riveter, like me!!


__________________________________________________
Life is not a rehearsal.
2010 VFR 1200F DCT
2010 R1200GS(gone)
1986 K100 Silver(gone)
2012 K1600GT(gone)
1984 K100RT Madison Silver(gone)
1989 K100LT Stratus Grey(gone)
1984 K100 Red(gone)
http://www.johnsdrivingschool.co
    

42Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 1:41 pm

nino


Life time member
Life time member
Thanks for tip Charlie. I did your way, released and turned from right to the left but didnt hear any (release) click. Anyhow, I turned TPS to the left totaly. Was it mistake?
Best regards

    

43Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 1:54 pm

charlie99

avatar
VIP
VIP
hi nino ....this could be an issue to turn it too far

when the throttle is wide open ...there is another set of contacts ....those contacts might get pushed too far if you have mooved the tps too far to the counter clockwise direction .

might be a good idea to go clockwise till you feel some tension of the mechanism binding with the switch then turn anticlockwise a few mm .

some one posted an internal view in here a while ago

just a heads up


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

44Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 2:28 pm

nino


Life time member
Life time member
Thanks Charlie, I just changed setting like you described. Now, when release throtle from fully open to close position I cant hear any click. Is it correct adjustment?

    

45Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 2:37 pm

charlie99

avatar
VIP
VIP
sounds like your micro switch is stuck anyhow nino ....(no click )

have you tried using a big long screwdriver with the blade on the tps assembly and put your ear to the handle end this would act like a stethescope and you might be able to hear if it operates ....you may need someone to help with this throttle twisting ?


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

46Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 2:43 pm

nino


Life time member
Life time member
@charlie99 wrote:sounds like your micro switch is stuck anyhow nino ....(no click )

have you tried using a big long screwdriver with the blade on the tps assembly and put your ear to the handle end this would act like a stethescope and you might be able to hear if it operates ....you may need someone to help with this throttle twisting ?

Charlie, just checked with better ear (left one). I can hear a click on full throttle. No click on the way to shut throttle.
Thanks

    

47Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 3:07 pm

charlie99

avatar
VIP
VIP
just a heads up

someone posted this a while ago

internals and wiring for testing


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

48Back to top Go down    Re: Things that BMW put there to annoy me on Sat Apr 13, 2013 7:25 pm

Ned

avatar
Life time member
Life time member
@nino wrote:
@charlie99 wrote:sounds like your micro switch is stuck anyhow nino ....(no click )

have you tried using a big long screwdriver with the blade on the tps assembly and put your ear to the handle .... ?

Charlie, just checked with better ear (left one). I can hear a click on full throttle. No click on the way to shut throttle.
Thanks

Wow, this thread is 3 years old already. That means that I had my K100 for over 4 years ... how time flies...

Nino: if you are not sure about the adjustment, just unplug the device and test it by going out for a ride. The full throttle switch is only used when you are at full throttle and slow speeds... hmmm... full throttle...we dream about it, but i think that most of us never twist the handle that much Smile What I am saying is that there is no harm done by disconnecting the thing for testing.

I did this mod 3 years ago and had no change in fuel consumption. To me it was a gain as the bike rides better at lower speeds around the suburbs.

As this is now a mature mod, I wonder what you all think about it. If you made the modification did you find it useful?

Two questions:
a. was it useful?
b. I ride open roads or suburbs mainly?


__________________________________________________
I reserve the right to voice my opinions on any subject known to man
Ned

05/1986 (K55) K100RS Motorsport (Europe), Production Code: 0503, 110k km, VIN:0140519 (SOLD)
1976 Honda Goldwing GL1000 (naked)
1997 BMW K1200RS red, VIN: WB10544A1VZA22667
    

49Back to top Go down    I might just as well chime in here too... on Sat Apr 13, 2013 10:44 pm

ibjman

avatar
Life time member
Life time member
Ned,
I agree with you that the TPS switch tends to aggravate the herky jerky motion when going from fully closed throttle at speed to throttle on again. It is one of the features of my 85 that I love least.
I would suggest that your original post might have been a bit "overkill". (just my opinion).
I might suggest that if you can't live with the effects of the closed throttle portion of the TPS, that a better compromise than just disabling the entire part, would be to intentionally "mis-adjust" it slightly so the throttle off function never quite occurs.
By doing this, you eliminate the lurch, but retain the benefit of the WOT enrichment.
Second, by disconnecting the vacuum sense hose from the fuel pressure regulator, you are essentially "over fueling" the engine in most parameters. I think you mentioned somewhere that it runs "much the same" with or without the regulation of the pressure. I would suggest that even though subtle changes in fueling pressures may not be readily apparent from the seat of your pants, they are necessary for a host of good performance reasons. Not to mention, a cleaner exhaust emission environmentally.
Last, as for the vacuum sensing switch on the early 85 and earlier.....mine has one, I have tested it and verified that it functions.
In my tests, it appears to switch ON at a very low vacuum setting.
I was never able to completely learn it's engineering reason or purpose, but I have to conclude that it simply signals that the engine speed is sufficient to have at least cranking vacuum when starting, perhaps to signal the onset of fueling or maybe a timing change. I would further guess that it might be beneficial to prevent flooding and hard start in certain situations.
What I do know is, that even though we may not be able to see/feel any difference in using it or not, conversely we can't see that it causes any harm.
I choose to believe that all engineering features are added at quite some expense and few of them turn out to be "Failures". Most engineering goofs are corrected in some manner during the early years of any model by factory service bulletins.
My advice to you (although you didn't ask it) is in MOST conditions, your best overall option is to stay stock.
Most "alterations" made for perceived performance improvements, result in an equal or worse downside in some other way.
"Just because it's louder, don't mean it's faster"......LOL

    

50Back to top Go down    Re: Things that BMW put there to annoy me on Sun Apr 14, 2013 1:09 am

charlie99

avatar
VIP
VIP
i think the injection kill is nothing but a promised effort on behalf of all the manufacturers trying to get aproval for clean air emmissions in electronic motors way back then .....

if things are fitted up right (read inlet manifold leaks and injectors etc ) there is little backfiring at all to be noticed ...and i would add that the power returns in a smoother fashion than going from a completly leaned out engine cylinder ...and on the power again due to overshoot of the throttle control ( i predict less fuel is used during this process of continuous charge process )

i imagine that it all falls in a heap once you extend the engine braking down a long continuous hill for which i believe the feature was installed ...i would have loved to see some interaction of the speedo pulse counter involved in the kill injection process ie count 300 before turning off if no throttle is open ....personally i only know of just a few locations where this would happen in at least 600 ks from my place .most if not all bring you back on throttle durring the descent ..or is that the way i ride anyhow ?

crikey the old bmw is still squirting fuel three times before the inlet valve opens again durring normal running ...but it works ...

i think there is enough anecdotal evidence on here and other forums and places that prove that this process has little effect on the running or longetivity of our old girls and their performance .

try it ,,,if you dont like it ...put it back

for me ....i love it ...it certainly has smoothed off the performace of hills and twistys with far less dramatic change in bike balence fore and aft durring critical line setups in and around corners . and cetainly looks after the transmission and wear on tyres due to such changes ...especially round town .


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

Sponsored content


    

View previous topic View next topic Back to top  Message [Page 1 of 3]

Go to page : 1, 2, 3  Next

Permissions in this forum:
You cannot reply to topics in this forum