95 K1100LT intermittent stalling problem

[lvmonster]

Hello, I have an annoying problem. At odd times, my bike will stall... usually when hot (not uncommon here in Vegas) and when running at low speed (slowed to stop at light/sign).

Now, this does not happen all the time, in fact, it's only happened to me about 3 times since May when I bought it used (it's one of the reasons for the sale). Once, it kinda coughed and died and the other times just as I stopped at a sign/light it would stall. On those occasions, it started right away. But, last week at highway speed I pulled in the clutch and closed the throttle for a hand rest, it died completely, and coasted down from 75mph to about 25mph. I attemped to restart several time while coasting, finally shutting off the key for a spell... at 25mph, I turned the key back on and restarted it with no further problems. (no lack of power, no more stalling, nothing) It was hot on the road, (about 115 or so at least) and the bike had been run at speed for better than 45 miles.

The former owner said he had had the bike in and checked and it had been behaving itself for the most part, but he had no more patience for it. He also said that he had replaced the fuel filter, which hadn't fixed the problem.
If anyone has any ideas about this, I'd love to hear them. I will be happy to supply any and all details and or progress.

thanks!

monster

[deilenberger]

Originally posted by monster
Hello, I have an annoying problem. At odd times, my bike will stall... usually when hot (not uncommon here in Vegas) and when running at low speed (slowed to stop at light/sign).

Now, this does not happen all the time, in fact, it's only happened to me about 3 times since May when I bought it used (it's one of the reasons for the sale). Once, it kinda coughed and died and the other times just as I stopped at a sign/light it would stall. On those occasions, it started right away. But, last week at highway speed I pulled in the clutch and closed the throttle for a hand rest, it died completely, and coasted down from 75mph to about 25mph. I attemped to restart several time while coasting, finally shutting off the key for a spell... at 25mph, I turned the key back on and restarted it with no further problems. (no lack of power, no more stalling, nothing) It was hot on the road, (about 115 or so at least) and the bike had been run at speed for better than 45 miles.

The former owner said he had had the bike in and checked and it had been behaving itself for the most part, but he had no more patience for it. He also said that he had replaced the fuel filter, which hadn't fixed the problem.
If anyone has any ideas about this, I'd love to hear them. I will be happy to supply any and all details and or progress.

thanks!

monster

Hi Monster..

I can't say I have direct experience with a '95 K11 - but a few ideas I'll pass along:

1. Idle speed: What is the idle speed set to? It should be 900-1050RPM. If it's lower than this, you may get an occassional stall as you describe.

2. Fuel filter: Eeven though the former owner replaced it - it doesn't mean it is good. A brand new fuel filter used with a dirty tank of gas can be plugged instantly. A fuel filter that never sees any water or junk in the fuel will last indefinately. Never rule out a fuel filter. :)

3. Ignition switch: With the engine not started - turn the switch to the RUN position and wiggle it. If the dash warning lights change brightness when it's wiggled - your ignition switch needs cleaning. There are FAQ's on doing this on the IBMWR website, and if you want photos of doing it see:

http://www.eilenberger.net/K75S/IgnitionSwitch/index.html

This is not an uncommon cause of this type of problem. Had it on my K75S - cleaning it solved the problem.

4. Crankcase breather tube: This is the sorta Z shaped tube that connects from the airbox about your throttle bodies down to the engine crankcase. It's more or less in front of the area the coils are located, behind the black box on the end of your throttle bodies. These dry out and crack with great regularity (replacing it every 3 years or so is a good preventitive thing to do.).

If you feel/see any cracking in it - replace it. It can be replaced without removing anything else from the engine - it just looks like it can't.

Cranks in this hose allow excess air into the intake that the computer doesn't know about - making the bike run lean. The effect is most pronounced at smaller throttle openings.

5. Motronic connector: This is the big connector that goes from the wiring harness to the computer. R&R this connector a few times... the contacts in them have been known to become marginal over time, and the rubbing action from removing and replacing the connector are usually enough to fixt the problem.

6. Starter motor: Sounds odd doesn't it? What does the starter motor have to do with the bike continuing to run after it's started? Well - it's kind of an almost mystery, but if the starter motor gets dirty inside (from worn brush deposits) it can cause a leakage path that ends up killing the bike. You didn't mention the mileage on the bike - but any K bike with more than 60k miles on it is a candidate for this very odd failure. See the IBMWR K-tech FAQ pages for info on removing and cleaning the starter. Isn't a terribly difficult job.


OK - which to do first? I put them in the order I'd do them in.

Other stuff: The symptom you gave for last week might not be related to the other stalling incidents. It is possible that you suffered from vapor lock momentarily - 115F is pretty warm. There is the possibility that a partially plugged fuel filter will make vapor lock worse..

HTH,

[wolftroy1]

Originally posted by monster
Hello, I have an annoying problem. At odd times, my bike will stall... usually when hot (not uncommon here in Vegas) and when running at low speed (slowed to stop at light/sign).

Now, this does not happen all the time, in fact, it's only happened to me about 3 times since May when I bought it used (it's one of the reasons for the sale). Once, it kinda coughed and died and the other times just as I stopped at a sign/light it would stall. On those occasions, it started right away. But, last week at highway speed I pulled in the clutch and closed the throttle for a hand rest, it died completely, and coasted down from 75mph to about 25mph. I attemped to restart several time while coasting, finally shutting off the key for a spell... at 25mph, I turned the key back on and restarted it with no further problems. (no lack of power, no more stalling, nothing) It was hot on the road, (about 115 or so at least) and the bike had been run at speed for better than 45 miles.

The former owner said he had had the bike in and checked and it had been behaving itself for the most part, but he had no more patience for it. He also said that he had replaced the fuel filter, which hadn't fixed the problem.
If anyone has any ideas about this, I'd love to hear them. I will be happy to supply any and all details and or progress.

thanks!

monster

Monster,
I would be willing to bet this never happens in cooler weather. I have experienced this same problem first hand when I brought my bike (1995 K1100LT) back from Italy to Tucson, AZ. It was a simple fix from the guys at Iron Horse Motorcycle (done back in '96). The culprite is the fuel vacume hose, apparently it gets so hot it suffocates the engine, they took it off and replaced it with a BMW modification for hot weather. I'm being vague because it's been so long and I just don't remember the whole deal. Anyway, I still have the bike and I have never had a problem since. Granted I now live just south of Seattle, WA, but going over the mountains to 90 - 100 degree heat doesn't cause her to miss a beat.
Hope this helps.

Troy

[AntonLargiader]

Originally posted by monster
Hello, I have an annoying problem. At odd times, my bike will stall... usually when hot (not uncommon here in Vegas) and when running at low speed (slowed to stop at light/sign).
This is exactly how SWMBO's R1100GS was running after I had let the valves go WAY too long without adjustment. They had closed up some and one was really tight. Set the valves right - and the idle is now rock-solid.

[lvmonster]

Thanks for all the feed back so far... as to my bike... It's got less than 32k on the clock, it idles about 1000 or so, I run 100 octane gas, haven't run it in much cooler weather so far (but I'm interested in the hot weather mod thingy). I'm waiting for the new BMW of Las Vegas to open so's I can get a (hopefully) good shop's checkup on the beast. The first thing i'm gonna do, however, is do the plug thing on my Mototronics box... (always start with the simple things) Then, I'll get more involved..

Keep the shiny side up guys!

monster

[darlingl]

Your stalling problem may be as simple as an intermittent ground. Check to make sure your Motronics unit is secured tightly. That's what my problem was!

[username]

sounds like youve got some microsoft software on that thing...

let us know how it goes.

[CustomSarge]

I wouldn't count out the Hall sensor, either. Especially if it gets chronic at high temps, or heavy rainfall.

[eric2]

I have a friend who's LT does the same
thing. First noticed in bike week traffic at Daytona. When his did it you could
look in the gas tank and see gas starting
to boil. Let it sit for 10-15 minutes
and it worked fine.

The dying while driving thing sure sounds like a hall sensor though

Best,
Eric

[NWKRider]

I have a 95 K1100LT also. Experienced the same problem over three years. two local dealers no help. went with my best guess and replaced the temp. sensor. Problem solved. Also didn't like the way the lead wire was doubled back over itself then tiewraped to the frame.

[95864]

Hello, I have an annoying problem. At odd times, my bike will stall... usually when hot (not uncommon here in Vegas) and when running at low speed (slowed to stop at light/sign).

snip
monster

Mine used to do it at speed, at high altitude, at high temperature. It drome me crazy for awhile. I followed the instructions in an article on the IBMWR tech pages titled "The Electricity Has to be there Somewhere." Worked like a charm, no problems since. The procedure was to disconnect every connector on the bike, clean them and lube them with dialectric grease. It took about 6 hours. Problem solved. It was not the HES. I seriously doubt it is ever the HES.


I would be willing to bet this never happens in cooler weather. I have experienced this same problem first hand when I brought my bike (1995 K1100LT) back from Italy to Tucson, AZ. It was a simple fix from the guys at Iron Horse Motorcycle (done back in '96). The culprite is the fuel vacume hose, apparently it gets so hot it suffocates the engine, they took it off and replaced it with a BMW modification for hot weather. I'm being vague because it's been so long and I just don't remember the whole deal. Anyway, I still have the bike and I have never had a problem since. Granted I now live just south of Seattle, WA, but going over the mountains to 90 - 100 degree heat doesn't cause her to miss a beat.


I'd like to know more about this fuel vacuum hose. Does anyone know where it is? I'd just like to have a look at it.

Thanks,

[DonHamblin]

Monster,

"The Electricity Has to be there Somewhere." Worked like a charm, no problems since. The procedure was to disconnect every connector on the bike, clean them and lube them with dialectric grease. It took about 6 hours. Problem solved.


I do feel your pain! My FYK ('85 K100RT) drove me crazy for over a year! But knowing I might not be the only person too cheap to replace my motorcycle because of a little corrosion I put that IBMWR article together. You also might want to check out one titled, "What Do You Mean, "It Won't Start?" Usually only a problem with early "K's" but you never know.

If the electrical tune up doesn't do the trick, there is also a possibility that it's either the headlight shed relay (buying the Bosch part number can be less expensive than the dealer part), ignition switch, or kill switch. Those cost more money than dialectric grease so they might be saved until last.

Hope this helps,

Don

[deilenberger]

Mine used to do it at speed, at high altitude, at high temperature. It drome me crazy for awhile. I followed the instructions in an article on the IBMWR tech pages titled "The Electricity Has to be there Somewhere." Worked like a charm, no problems since. The procedure was to disconnect every connector on the bike, clean them and lube them with dialectric grease. It took about 6 hours. Problem solved. It was not the HES. I seriously doubt it is ever the HES.

Thanks,

Sorry, have to disagree on the HES. It on quite a few occasions
has been a failed HES.

I have seen and tested enough bad ones that it cannot be dismissed
this easily. They do sometimes go bad, with clear physical indications
if you know what to look for. And there is a fairly simple on-the-bike
test for ones that fail thermally. This test was devised by Jeff Dunkle.
It requires use of a hair-dryer:

Remove the cover over the HES and let the bike idle until it stops..
Then use the hair-dryer without heat to cool off the HES. Try
restarting. If it restarts, then turn the heat on the hairdryer and
heat the backing plate on the HES. If it has a problem the bike
will stop very soon after the plate heats up.

There is an excellent site on HES's (for the oilheads, but it is
amost exactly the same design on a K bike) at:

http://www.ebbo.org/ He describes the electrical test of an
HES. The wiring is slightly different (different connector) on a
K bike - but the colors are the same, so the test is easy enough
to do. It requires one LED and your bike battery.

He also describes replacing the sensors themselves. There
are exact replacements of the actual sensors available in the
US from Newark Electronics for $15/each. To replace them you
must have some mechanical skills and some skill in soldering fine
wires... the payoff is spending $30 instead of several hundred.

Best,

[95864]

Sorry, have to disagree on the HES. It on quite a few occasions
has been a failed HES.

I have seen and tested enough bad ones that it cannot be dismissed
this easily. They do sometimes go bad, with clear physical indications
if you know what to look for. And there is a fairly simple on-the-bike
test for ones that fail thermally. This test was devised by Jeff Dunkle.
It requires use of a hair-dryer:

snip
Best,

Thanks Don: As I recall you were one of the very helpful folks that helped me through my problem. Mine was so intermittant and unpredictable that I was certain it wasn't the HES. It seems to me that the material used in an HES should not lend itself to this type of problem. I am the last person anyone should rely on for HES analysis. Thanks again for all your help.

[bmwmick]

Thanks Don: As I recall you were one of the very helpful folks that helped me through my problem. Mine was so intermittant and unpredictable that I was certain it wasn't the HES. It seems to me that the material used in an HES should not lend itself to this type of problem. I am the last person anyone should rely on for HES analysis. Thanks again for all your help.

Here is a little data to add to Don's post. The HES unit on the K-Bikes is VERY reliable compared to the Oilhead HES. The hall effect sensor itself is spec'd to operate in an environment of -40c to +150c (-40F to +302F) and survives nicely mounted to the front of the K-Bike crankshaft. Here is the pinout for the K-Bike HES connector:


Mick

[Larry Amprim]

I had the same problem on a 1995 K1100 with 15k on it. Per an old time k bike expert in the Detroit area, I replaced the coolant temp sensor. Do not comfuse this with the sensor that drives the temp gauge. The collant temp is an intregal part of the fuel delivery system. It can be found in front of the airbox on an alloy spigot and requires a weatherhead socket to r&r.
Fixed my problem and now at least 50mpg@80 mph

[lvmonster]

Hey everyone! I finally got my problem solved. After getting a 12000 mile service, I had to take the bike back to the shop a few days later (long story won't get into it now... GRRRRR...) the darned thing stalled on me no less than 3 times on the way to the shop. Soooooo... when I got there I had the service writer snag one of his mechs to go for a ride... 30 minutes later, he came back with a MUCH better understanding of the problem. It seem that of the 2 temp sensors on the engine, the one that controls the fuel, spark, computer was intermittantly faulty. It has been replaced and thoroughly tested through the summer here in Vegas. Thanks to everyone for their suggestions and advice.

Keep it on at least one!

monster

[bmwmick]

It seem that of the 2 temp sensors on the engine, the one that controls the fuel, spark, computer was intermittantly faulty. It has been replaced and thoroughly tested through the summer here in Vegas. Thanks to everyone for their suggestions and advice.

Keep it on at least one!

monster

Thanks LV,
We REALLY appreciate the feedback.

[jamesbruce]

I have a 95 K1100LT also. Experienced the same problem over three years. two local dealers no help. went with my best guess and replaced the temp. sensor. Problem solved. Also didn't like the way the lead wire was doubled back over itself then tiewraped to the frame.
With one test ride, the previous pattern is broken, following installing a new temp sensor.

[kenk]

The K1100LTs has problems with cracks in the exhaust where the 4 pipes go into one under the left foot peg. My LT has 102K on the clock and it's cracked twice. My dealer (Engle’s in KC) told me this occurs on almost all of them over time.

Also, the brass exhaust gaskets have a tendency to loosen up. The first time was with only 20k on the bike in 1997. Recommend checking the torque of the gaskets and examining the exhaust for small cracks.

Both problems will cause the bike to run poorly at times (intermittent), while running very well at other times. With an air leak, the 02 sensor back by the catalytic converter is getting bad reading and provide that back to the Motronic.

When the bikes cold, the Motronic uses a standard map setting and is not taking inputs from the sensor. As the leaks get worse, the problem gets worse and more frequent.