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1Back to top Go down   1992 K100RS has crazy issues Empty 1992 K100RS has crazy issues Mon Oct 08, 2012 3:19 pm

Rabidchiwawa007

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This one is tough to describe, but here goes:


Also, since it is tough to describe, here is a video I took trying to show what happens.
The popping noises you hear in the video are not me hitting something with the camera, it's backfiring:

https://youtu.be/ep6jQg_Z48c



It will drag behind the throttle quite a lot. I know it has an exhaust leak, but it also backfires fairly consistently. It also has a dead-spot around 3-4k RPM. I'll turn the throttle enough to get it to 5-6k RPM and hold it there. It will slowly get up to 3-4k RPM, and then chuff around in there for a little bit. Then it feels like it breaks past it and finally revs up to 5-6k RPM. I'm a bit (very) stuck on this one. And based on my previous experiences with mechanics, I'll post here before I take it there!

It IS running on all 4 cylinders.
Compression on all 4 cylinders is good.
Spark plugs are clean and sparking.
Hall sensor is a known-good.


😕


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1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

2Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 3:37 pm

Inge K.

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Have you checked the TPS?


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

3Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 4:15 pm

DeRodster

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I would hazard a guess and say its a timing problem.
Certainly sounds like it.

R


__________________________________________________
1992 K1100LT 6455194
1943 BSA WM20
1979 Yamaha DT-175
1974 Triumph 3TA / 5TA
1974 Honda 100
1969 Honda 50
    

4Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 4:24 pm

Rabidchiwawa007

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I'll check the throttle position sensor asap

I was also thinking it could have to do with mixture, for example, if one of those butterfly things was stuck open??

Also, as far as it being a timing problem, I agree that that's what it sounds like, but isn't timing done automatically by the hall sensor, which is as I understand it, the crank position sensor?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

5Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 4:37 pm

Inge K.

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Rabidchiwawa007 wrote:I was also thinking it could have to do with mixture,

A 4V relies much on the TPS signal for calculating the mix.

Also check for intake leaks below TB`s....first check spark plugs for differences in colour.
(If a leak causing it, it have to a be rather big one.......)

Check these links: #1 #2


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

6Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 5:17 pm

yankeeone

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I would check for vacume leaks, also I had a similar problem, and found the air flow sensor flap was hanging up, at 18-2400rpm, after you are sure there are no leaks, do you have a air flow meter you can borrow?

    

7Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 5:39 pm

Inge K.

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yankeeone wrote:, and found the air flow sensor flap was hanging up, at 18-2400rpm, after you are sure there are no leaks, do you have a air flow meter you can borrow?

A 4V don`t have an AFM.


__________________________________________________
Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

8Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 5:43 pm

charlie99

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have a look at all the vacume lines along the throttle bodies and whereever they all join up etc ...sounds like something has become unstuck or broken , cracks in the rubber are notorious for hiding

on the 2 valve its pretty simple ....but on the 4 valve a little more complex

but check the tps connector for corrosion etc

good luck


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'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
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9Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 7:02 pm

Rabidchiwawa007

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Cool, thanks again everyone! I've got some work to do in the next day or two, and I'll post what happens.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

10Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 8:58 pm

Rick G

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It's lean from leaks in the inlet track somewhere quite possibly after the butterflys.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

11Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 9:26 pm

chrish8846

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Does the 4v have that crappy tube from the crankcase to the air box that always rots and splits also causes a bad air leak? I think it's more a air leak than timing.
Also when I did the K100 that I had I could only see one intake tube that looked questionable but when I pulled the TB's 3 were split.



Last edited by chrish8846 on Wed Oct 17, 2012 6:18 pm; edited 1 time in total

    

12Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Oct 08, 2012 10:49 pm

Rick G

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The 16v has a tube that splits and it goes to an oil extractor in the top section of the air box and then to the TBs via more tubes that split and the oil returns to the crankcase via more tubes that split. It may pay to remove the lower section of the air box, then you can see more of this wonderful setup. 1992 K100RS has crazy issues 610153


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

13Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Tue Oct 09, 2012 12:16 am

Rabidchiwawa007

Rabidchiwawa007
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Sounds like an ingenious design! 🇳🇴

Anyways, I messed with the TPS. I didn't set it exactly, but the bike revs MUCH smoother in neutral. I was actually able to ride it today, so we're making progress! Razz
It also takes awhile to rev back down as well.

So for example, if I rev it up to 5k RPM, it takes maybe 3-5sec to get back down to idle. This screams pretty big air leaks to me, can anyone confirm?



When I'm riding it, I can't turn the throttle too much or the bike just chokes, loses power, feels like it's been flooded or something, and just feels like it stops pulling all together. If I turn the throttle bit by bit, however, very slowly, it stays pulling fairly consistently.

So for example, if I'm in first running at 2.5k RPM and I grab enough throttle to get to 5k RPM, it'll just choke and lose power.

But, If i'm in first running at 2.5k RPM and just slightly turn the throttle enough to get to, say, 2.6k rpm, and then when I'm at 2.6k, I'll turn it a little more to get to 2.7k, for a gradual and slow increase in RPM and speed, it seems to not choke nearly as bad and pulls more consistently.

Does this also scream major air leaks?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

14Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Tue Oct 09, 2012 1:12 am

Rick G

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Sure does. When you touch the starter button as well as engaging the starter it sends a signal to the ECU to enrich the mixture for an easy start, hot or cold it does it. when the engine is running also the starter wont engage due to the ECU removing the Earth for the starter relay. So when it bogs down press the start button and see if it makes a difference. If it does go better then it is a leak for sure.
Also there is a tube at the back of the TBs that connects to all 4 TBs and joins into one tube then goes to the oil whirly gig that seperates the oil from the air from the crankcase vent. If it has come of the TBs and on my K11 it was off when I got it, that could also cause the leak.
Once again you need to get at the back of the TBs by removing all of the airbox that you can easily do.
My K11 was running so poorly that the PO was told by some guru BMW idiot mechanic to sell it to the wreckers because the engine was shagged. All it was was leaks that I fixed before I even started it and it is now a sweet bike.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

15Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Tue Oct 09, 2012 4:05 am

DeRodster

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Fantastic, such a wealth of knowledge on here.
So glad I found this site.

My second thought was "air leak", hence the popping.
However as I am not totally or even in any small way familiar with my own machine...yet, I too will look to other's for guidance.

Every little helps !....now who says that ?

bcnu

R


__________________________________________________
1992 K1100LT 6455194
1943 BSA WM20
1979 Yamaha DT-175
1974 Triumph 3TA / 5TA
1974 Honda 100
1969 Honda 50
    

16Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Wed Oct 17, 2012 3:00 pm

bjarnek100

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Just a thought....and a question to those who knows a loit more than I do Very Happy

Could it be a malfunctioning fuel pressure regulator, making the bike act up like this?

Again, just a thought...

    

17Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Sun Nov 04, 2012 2:16 pm

Rabidchiwawa007

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So here's what I've done:
_____________________________

Replaced all components underneath the butterflies, meaning:
-The intake manifolds and the O-rings under them
-The rubber hoses that connect the intake manifolds to the throttle body.

Checked the split hose system for air and oil behind the air box, all seems to be okay.

Adjusted the TPS to 0.375v with the throttle completely closed. This means I adjusted it with the idle screw all the way out to ensure the butterflies were closed. Was this the right way to do it?

Cleaned air filter (which wasn't too bad to begin with) and put it back in

Replaced cracked fuel line with new high pressure line
_________________________________

I think that's about it. So here's the thing.. the same issue is still there, but it's not NEARLY as bad. At this point, I would ride the bike the 4 miles to school and back, but I wouldn't take it on a road trip or anything.

There is still an exhaust leak, which I believe I have narrowed down to being one of the copper gaskets in the exhaust port that needs replacing. Could this cause actual running issues?

Here's the other thing: The bike seems to run and rev better with the TPS set to around ~.600v instead of .375v. In fact, it was better to the point that the issue with it bogging down upon twisting the throttle seemed to not be there any more. Does this mean anything?

Thanks in advance!


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

18Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Sun Nov 04, 2012 2:33 pm

Inge K.

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In the previous post FPR is mentioned...not a bad idea...
have the fuel pressure checked, should be 2,5 bar.


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

19Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Sun Nov 04, 2012 4:27 pm

walfish

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I personally would set up the idle screw before I set the TPS, loosen off both screws on the TPS, balance your throttle bodies, set the idle at 950 and only when that is all done then set the TPS.


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1992 K100RS has crazy issues Uk-log10
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20Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Sun Nov 04, 2012 10:18 pm

Rabidchiwawa007

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cool cool, i'll take a look at retuning that TPS then.

also, "bar"? what is 2,5 bar? Is there a certain PSI I'm looking for? I'll most likely split off the fuel rail with a T connector and put a fuel pressure gauge on one side.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

21Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Sun Nov 04, 2012 10:23 pm

Crazy Frog

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Rabidchiwawa007 wrote:what is 2,5 bar?

36PSI

What is a bar?.... Click here to see


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22Back to top Go down   1992 K100RS has crazy issues Empty Re: 1992 K100RS has crazy issues Mon Nov 05, 2012 5:14 pm

Rabidchiwawa007

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ungaas wrote:I personally would set up the idle screw before I set the TPS, loosen off both screws on the TPS, balance your throttle bodies, set the idle at 950 and only when that is all done then set the TPS.

My only question with that is: The position of the TPS has an effect on the idle speed. So I could set the idle to 950, then change the position of the TPS, and the idle could raise or lower depending on which way I move it. So setting the idle before setting the TPS seems out of order to me. Does that make sense at all, or am I missing something else?


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1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

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