95 K1100LT - engine surging / hesitation / rough running

[Hilltopper46]

I wanted to move this off the "What did you do to your brick today" and into its own thread, because I have a feeling it will take me a while to work through this issue, although I hope not.


Some background: I bought the bike at the end of April.  It had 2013 tags on it so it hadn't been run (much) for 4-5 years. I knew I needed to put a battery and a front tire on it. I sucked as much gas as I could out of the tank, and put a gallon or so of fresh gas in it with a bottle of Techtron.


When I got it running, it ran well, but I soon learned I had a bad exhaust system. I made the decision to have it welded due to the low number of miles I expect to put on the bike, and finished up the installation early yesterday morning.


Before the exhaust replacement, I put about 200 miles on it (one tank of fuel) and towards the end of that thought I was noticing some surging when running at constant speeds.  The bike always accelerated well. 


Yesterday I took the bike into town, and filled it with no-corn, 91-proof gas at the local Shell station. I stopped at the post office and the hardware store.  By the time I got home the bike was surging pretty significantly.


I got it home and drained the fuel tank and pulled it. I then pulled apart and sprayed electrical cleaner into every connection I could find. Specifically I inspected the 4-pin connector under the tank and it is OK. I also replaced the fuel filter which the PO had relocated to outside of the fuel tank. I test drove it and it was worse than earlier in the day.


After posting in the "What did you do to your brick today?" forum, today I insulated the fuel filter and ran the bike down the road, in less than two miles it was surging - now it is almost "bucking".  When I got home, I felt the filter and the fuel rail and it was still cool to the touch. So I am relatively certain that the issue is not fuel vaporization.


I do plan to move the filter back into the tank sometime in the future.


I have the following questions (other than the obvious one - what in the world is wrong with this bike?  :dunno2:  ):


1. I tried the propane gas air leakage test, but I have a Mapp Gass torch - is there any issue using Mapp Gas? I did not have any change in engine note while doing the test.


2. is there anything about the exhaust system that could cause this issue or make it worse? Anything related to the oxygen sensor?


3. Does it make sense to run a fuel pressure test? (short answers are cheerfully accepted)?


4. Could it be a TPS?


5. Is there a page like this (http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm) only for Motronic systems?


Thanks in advance. I have really appreciated this forum.
** edited in an attempt to fix font size issues.**

[Scott_]

Could be that the Techron knocked loose some crud in the lines that could now be clogging the injectors.
I'd suggest continuing with the Techron in the fuel.
Have you checked the plugs/wires, though I'm still thinking that it's fuel related.
You might also want to check for vacuum leaks, not uncommon with old rubber hoses.

[Laitch]

1. . . .  is there any issue using Mapp Gas? . . .
2. is there anything about the exhaust system that could cause this issue or make it worse?
3. Does it make sense to run a fuel pressure test?
5. Is there a page like this (http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm) only for Motronic systems?

There are two threads that discuss a surging K1100 in depth and were originated by mystic red. He created an excellent pictorial about troubleshooting rubber components and other elements of the fuel delivery system here. http://www.motobrick.com/index.php?topic=624.0

The thread that led to that pictorial is here. https://www.motobrick.com/index.php?topic=269.0

My reading comprehension drops off this late but I didn't find in your posts that you have changed the air filter. Air restriction causes surging too. Removing the filter from a K11 LT can be challenging but you need to inspect the filter and air box interior if you haven't yet.

Here are responses to some of your other questions.
Mapp gas is more costly than propane, but it would work like propane. It is more volatile. You didn't self-immolate, so that's good I guess. Mapp won't be any better at finding leaks than propane. Some members have used aerosol carb cleaner. With any of them the revs will increase if there is a leak. Take a look at mystic red's propane leak-finder. Should you recheck for leaks using his rig?

It makes sense to test the fuel pressure regulator as a step in the orderly assessment of your bike's fuel delivery system after you have checked its lines for cracking. Right now, check to be certain no vacuum ports along the throttle body assembly are uncapped.

I haven't found a document dedicated to K1100 Motronic troubleshooting as extensive and well-organized as Vogel's troubleshooting guide for the K100 but as he states in the yellow panel on the opening page, the principles are the same. There is this. http://www.largiader.com/articles/motronic.html

Have you double-checked the fuel filter's orientation? Restore it to its position within the tank.

Your bike needs a tuneup after all systems are checked for integrity. The wide-spread belief is that 16-valve engines maintain valve clearances within spec. Checking yours might be appropriate followed by balancing of the throttle bodies and setting of the idle; however, that's the last procedure in line.

Your bike has been idle and neglected. It needs a thorough review and refreshment where necessary. You might need some refreshment during all this, too. Cold whiskey was mystic red's choice.

[Hilltopper46]

Here's what I did today.


I pulled the right hand fairing lower off and pulled the air filter out and looked it over.  It could be better, but it wasn't plugged.  The worst is there is an area near the front of the filter where oil had dripped on it and soaked a few pleats the entire width of the filter. The airbox was clean with no mouse nests, etc.


I found an old propane torch that I could push a length of tubing over and laid propane down near the base of the intake manifolds. I think I am hearing a change to the engine note when I do that, but the rpm does not increase, if anything, it decreases 50 or 100 RPM.


For kicks and giggles, I checked the Motronic for error codes but all I got was a fan test and no error codes.  I also used the diagnostic connector to test the TPS as shown somewhere - that worked correctly, but I doubt it is a conclusive test of the TPS.


Tomorrow, I'm going to do the propane torch thing some more - I will likely pull the left fairing lower off which will give me some better access to the bushings, etc.

[wally.fisher]

Here's what I did today.


I pulled the right hand fairing lower off and pulled the air filter out and looked it over.  It could be better, but it wasn't plugged.  The worst is there is an area near the front of the filter where oil had dripped on it and soaked a few pleats the entire width of the filter. The airbox was clean with no mouse nests, etc.


I found an old propane torch that I could push a length of tubing over and laid propane down near the base of the intake manifolds. I think I am hearing a change to the engine note when I do that, but the rpm does not increase, if anything, it decreases 50 or 100 RPM.


For kicks and giggles, I checked the Motronic for error codes but all I got was a fan test and no error codes.  I also used the diagnostic connector to test the TPS as shown somewhere - that worked correctly, but I doubt it is a conclusive test of the TPS.


Tomorrow, I'm going to do the propane torch thing some more - I will likely pull the left fairing lower off which will give me some better access to the bushings, etc.

In the post above Laitch posted a link to largiader, the link includes how to test your tps, but if you can test between pins 1and4 it should read no more than 0.8 volts, unstarted with ignition on. What of the air pipes behind the throttle bodies are they in place or in good condition.



Sent from my iPad using Tapatalk

[bizzaro]

In the post above Laitch posted a link to largiader, the link includes how to test your tps, but if you can test between pins 1and4 it should read no more than 0.8 volts, unstarted with ignition on. What of the air pipes behind the throttle bodies are they in place or in good condition.



Sent from my iPad using Tapatalk

I am pretty sure it should be .375 volts?? Wally,  did you mis-state the value in this thread in your last post?   I am  sure .38 would be fine, not sure about .8??  Mine is at .40 and seems to work fine.

Previous post from Wally in another thread concerning TPS?
"Cannot do a click test on a k1100 tps, it must be set using your multimeter, the setting should be .38 with ignition on, not started."

[Hilltopper46]

I applied the propane test to the bike again today.  Again, when I apply propane at the base of the manifolds, the bike changes exhaust note and loses a little RPM, I believe that the propane is enriching the mixture and causing the RPM drop. I believe the propane ingress is through the o-ring between the manifold and the head and it is doing it on at least three out of the four manifolds.


So, I have pretty well decided to remove the throttle bodies, manifolds and related parts to eliminate this.  I just wish that I had a more definitive diagnosis as to the cause of the surge.


Thanks for the feedback on the TPS.  I was using the procedure from the largiade page:

We can do a quick check of the TPS setting on Motronic 2.2 (and I think 2.1) using the 3 position diagnostic connector. I've tested this on my '96 R1100RT and it works.  I'll check my '93 K1100LT (MA 2.1) one of these days and let you know but I'm pretty sure it works the same and in addition, it lights the TEMP lamp so you don't even need the LED.
Ignition OFF
Ground Pin #3
LED + on Battery + terminal
LED - on Pin #1
Ignition ON
[size=78%][/size]
[size=78%][/size]Now you should see the LED lit.  Slightly opening the throttle should make the LED go out.  If so, your TPS is within factory range[size=78%][/size].

When it says "slightly opening the throttle" all I had to do to make the light go out was take the slack out of the cable.

[bizzaro]

It takes a bit to get the hang of reading the codes.  Did you get it?  First, It is counter intuitive as you need to count the dips and not the pulses.  Just seemed mentally awkward for me at first.  Once I got it,  it was easy. If you want me to explain it in more detail I will. The link Laitch sent you is correct for my bike. I was given a link to a Frank Werner PDF that did not work with my 94K11LT....................Though it doesn't sound like it will help you any!  It would seem you have found an issue? Hopefully it will take care of the problem.

Also I inadvertently got my fan to pulse on and off when learning to read fault codes.   Do you have the fan test info or a link.  I would like to know how I did it!  :hehehe :hehehe

[wally.fisher]

I am pretty sure it should be .375 volts?? Wally,  did you mis-state the value in this thread in your last post?   I am  sure .38 would be fine, not sure about .8??  Mine is at .40 and seems to work fine.

Previous post from Wally in another thread concerning TPS?
"Cannot do a click test on a k1100 tps, it must be set using your multimeter, the setting should be .38 with ignition on, not started."

Yes, you're right, too many beers combined with phat fingers. Apologise for the confusion.


Sent from my iPad using Tapatalk

[Hilltopper46]

Also I inadvertently got my fan to pulse on and off when learning to read fault codes.   Do you have the fan test info or a link.  I would like to know how I did it!  :hehehe :hehehe

I played with this again this morning before I took the intake manifolds off. If I keep pin #1 grounded when I turn on the key, the fan test starts.  If I turn on the key and then ground pin #1, I get error codes.  I got the two halls sensor codes (which is normal).

[Hilltopper46]

I pulled the intake manifolds out this morning. I found two of the bushings ripped - although one of them may have happened as I removed it.


I also found all the o-rings under the manifolds hardened and you could see where the WD40 that I had sprayed around the bases tracking in.  Worse than that, you can see where dirt has tracked in under the o-ring on #2 intake.


I'm in the process of ordering parts.

[Hilltopper46]

Ordered parts to day.  I found the injector o-rings at NAPA - two kits of 4 o-rings each for under $10.


Clean up the throttle bodies - I can't believe how much dirt was in them.


I ordered the BMW bits from a local-ish BMW dealer who will mail them to me when they come in - about 1-1/2 weeks.  I asked him to check availability before he placed the order - at first he said the bushings weren't available, but then realized he misskeyed the part number. He had the o-rings in stock.


I'll update this thread when the parts come in and I get them installed.

[Laitch]

I ordered the BMW bits from a local-ish BMW dealer. . .

I doubt if you'll get M&Ms with that order then. :giggles

[Hicks1109]

I had.nothing but trouble with mine after fitting a k&n air filter. Just ran week.. Surged. Rough tick over. In the end I put k1200 rs injector rail on it with a 3 bar regulator of a r1100s wouldn't believe the difference that made. Than I put some slightly higher flowing injectors in it. And it pulled like a train. Impressive. Would spin its back wheel. Low down grunt. That was just before it blew the head gasket. So I put the 1200 motor in it. Struggling with loom and ecu at the mo.

[Hilltopper46]

Ordered parts to day.  I found the injector o-rings at NAPA - two kits of 4 o-rings each for under $10.


Clean up the throttle bodies - I can't believe how much dirt was in them.


I ordered the BMW bits from a local-ish BMW dealer who will mail them to me when they come in - about 1-1/2 weeks.  I asked him to check availability before he placed the order - at first he said the bushings weren't available, but then realized he misskeyed the part number. He had the o-rings in stock.


I'll update this thread when the parts come in and I get them installed.

The bushings and o-rings arrived today and I got them put in. It started after a bit of cranking. It helped when I plugged in the #1 injector. 🤣

I balanced the throttle bodies. They weren't off very much.

I took it for a test run, and it's better than it was, but it still seems like there is some hesitation at neutral throttle. I'm going to go ahead and put the rest of the plastic on it and try to get some miles on it.

Will be running some Techtron through it.

Sent from my SM-G930V using Tapatalk

[Hilltopper46]

I'm still working my way through this.  I've ridden it about 100 miles since I got it back together and it still has periodic hesitation with partial throttle.  One thing I noticed  the last time I rode it is that If I work my throttle with slight acceleration and deceleration right at the point that I want to ride, it runs smoother than if I try to hold the throttle steady.

Next on my list are to:

1. run the Motronic error codes again
2. run a fuel pressure test
3. do a resistance check of all the sensors

[Filmcamera]

I know it sounds odd but have you checked the voltage output of your alternator?

Mine went bad a few months ago and when it is was bad the revs would surge up and down when I had the throttle steady. Turned out the alternator was kicking out up to 17 V and that was messing with the ICU

[Hilltopper46]

I know it sounds odd but have you checked the voltage output of your alternator?

Mine went bad a few months ago and when it is was bad the revs would surge up and down when I had the throttle steady. Turned out the alternator was kicking out up to 17 V and that was messing with the ICU

I'll add that to the list - easy to do. Thanks.

[Hilltopper46]

Motorcycle says: Motronic fault code 1215 Throttle butterfly angle sensor. I did a voltage check on the variable voltages looking for a dead spot but didn't really find anything conclusive. It did seem to me that the rise in voltage wasn't very linear on the one side.


It also says 2343 - mixture setting at limit, any insight into this code would be appreciated.

[wally.fisher]

2343 could be the oxygen potentiometer, it is a 10 turn pot, my recollection is anti clock to lean out or clockwise to richen the mixture. I posted some pics with some really good info in setup of oxy pot and tps.


Sent from my iPad using Tapatalk

[Hilltopper46]

2343 could be the oxygen potentiometer, it is a 10 turn pot, my recollection is anti clock to lean out or clockwise to richen the mixture. I posted some pics with some really good info in setup of oxy pot and tps.


Sent from my iPad using Tapatalk

I'm pretty sure this bike does not have a CO pot as it has an o2 sensor in the exhaust.

Thanks.

[wally.fisher]

Possible im wrong do you have close up photos of left side near battery.

Sent from my SM-G925F using Tapatalk

[Hilltopper46]

Yesterday I took the battery out of the bike as it had run down enough doing error codes and and voltage checks to where it wouldn't start the bike.  I put it on the charger today, and while it was charging, I took the bolt out that holds the ground cable for the battery and made sure the connection was clean. I did that because of this thread: http://k11og.org/forum/viewtopic.php?t=7277&highlight=2343

After I got the battery  back in the bike I set the TPS by voltage.  It was out quite a ways, when I started it was almost .8 volts.  I got it set to .380 and tightened the screws back up.

Then I took it for a test ride - I put 10 miles on it and the surging is much better.  I still can sense it a little, but only just a bit.  By the end of the ride I was actually enjoying myself.

So - it might be fixed.  I wish I could tell anyone for sure what fixed it.  Probably the the TPS setting, given that I had a TPS code. It might have been a grounding issue, of may have simply been that Techron-rich fuel has been setting in the tank for another couple days.

Unless something else comes up this thread will likely pass on into posterity.

Thanks to everyone who made suggestions.

[Hilltopper46]

I wanted to add an observation to this thread that might be helpful to someone in the future -  after adjusting the TPS, the bike is much more "cold-blooded" - I had wondered previously when reading that the bike could be cold-blooded why this one did not seem to be so - it certainly is now.

I'm guessing that the mal-adjusted TPS was enriching the idle mixture.

I have another 40 miles or so on the bike and it is running much, much better - it is actually a joy to ride, now. I do need to re-balance the throttle bodies as it idles roughly. I may actually need to raise the idle speed a little bit as well - seems to be idling around 800 RPM after it warms up.

[wally.fisher]

Idle should be at 950-1050 rpm.

Sent from my SM-G925F using Tapatalk