Hi guys I am a bit nervous to post something regarding the Hall Sensor but hear it goes.

I currently bought a 1994 BMW K1100LT has about 64K miles on it. So far I put new spark plugs, new Air Filter, Fuel Filter and pump, replaced brake master cylinder and front brake pads.

Story time (sorry for lengthy write up)...
month ago me and 2 buddies decided to ride, it was my first go at riding it with all the upgrades/ changes. after about 30min into it, it stalled. min later fire it up and we keep going. but something is wrong its acting up and jumpy and like my buddy said like a bucking bronco!
they suggested it was fuel related ( having changed the whole fuel pump and filter I thought might be something I screwed up). So I checked all the stuff in the tank and made sure it was tightened up all connectors put it back and found no issues of a bucking bronco! Sweet!

Few days ago we had some great 68 deg. weather here in Ohio and I decided to ride to work. Ride in was about 50deg and no issues with bike.
Later that day (68deg now) I am riding and decided to keep riding before I got home. total ride time was about an hour and no issue what so ever. 
just about 5min before I am home at a traffic light I see my gear indicator flicker from 1 to 5 and back and forth with the engine sounding like it was going to putter out and stall. 
fortunately light goes green and I ride off to next light, as I pull in the clutch to slow down she puttered out and engine died! Yikes! I am in an intersection and immediately I hop off and run it off to the side of the street. throw my leg back over it and fired it back up. After that no putter, or flicker from the gear indicator but only rode it like 4 min as I was nervousness it was going to stall out again.
After that I put her in the garage and thought..ok I dont want to have that sorta issue if I have my wife on the back going for longer ride.

So I am under the impression that the Hall Sensor is going out (based on all the research I can find on multiple forums and google) 

With the wealth of knowledge on this forum i'm seeking for any guidance to properly install a new sensor. I already purchased a Bosch Ignition Hall Effect Trigger Sensor and its on its way. My fear is installing it incorrectly.
with alot of the post I have found it can be rather overwhelming to sort out.

Two things you need to do, if you haven't done them already, before going any further.

First, make sure the four pin tank connector is making good contact.  That is one of the weakest points on a K bike.

Second, clean out the internals of the ignition switch.  That switch is the source of a lot of strange electrical stuff. 

http://www.kforum-tech.com/electrical/Cleaning_ignition_switch/Cleaning_switch.htm

The gear position indicator switch(GPIS) is in a very nasty spot and gets abused badly in normal operation.  I wouldn't be surprised if it needs to be serviced as well.

It's a long shot, but I had quitting problems that were caused by a bad voltage regulator allowing the system voltage to drop so low that the fuel injection stopped working.

Last, when the engine quits because of the Hall Sensors getting hot, it usually takes 5-10 minutes before it will run again.

Side stand cutoff switch is the first thing that I'd check. A faulty gear indicator just makes the display go wonky and won't affect engine operation.

Put the bike on the center stand. Look at how the side stand cutoff switch is activated when you put the side stand up and down.  If you place a short section of vacuum hose on the tang that depresses the switch then that will make the side stand switch work more consistently.

ETA: If the Hall Effect Sensor is going out then the bike will usually die and then not restart until you've waited 5-10 minutes for it to cool down.

thanks Point Seven Five!
I have not done any of these but I will get started. I should have mentioned I replaced the battery as well not sure if that matters.
AS far as the GPIS...how does that go badly is there more on how to service that without taking it to a mechanic? 

I think since I already ordered the Hall sensor I will keep researching on proper way to install and install when ready (from what I read these things will go out)


thanks Duck!
I guess when I saw the gear indicator flicker I noticed the engine idle was dropping a bit. Making me think there is a correlation there.
I will definitely investigate this option as well. Is there a way of diagnosing if that is the fix? meaning do I have to ride more to see if its going to happen?

When you look at how the side stand switch is activated it should be pretty obvious how it works.

Diagnosis:  Get the bike running on the center stand. Push the side stand down a little ways. See if that kills the bike.  Once you put some vacuum hose on the tang you should need to push the side stand down further to kill the bike.

Personally, I would just keep the Hall Sensor handy.  That will go a long way toward preventing a Hall Sensor failure.  I've had 6 bricks now, and since I have spares, I've never had a Hall Sensor fail(knock on wood).

The GPIS is a bit of a PIA to get to.  You have to pull the swing arm and remove the battery to get it out of the bike.  I would hold off until I had a couple days to work on the bike, kinda like when I'm being incarcerated because of the China Death.

The side stand switch can be bypassed with a short piece of wire in the harness connection located behind the right side battery cover.

K-Dawg, I don't know how much wrenching experience you have, but having a mechanic do the GPIS is going to be pretty costly.  There is easily 7-8 hours of labor in just getting to the switch and I doubt you will find a mechanic that knows more about the guts of the switch than you do.  They'll just want to replace it with a new one for about $150.

The job itself isn't all that bad, it just involves removing a lot of the back half of the bike to get at the switch and some fussing with some small springs and stuff from the insides of the switch.  The main skills you need are perseverance to stick with it and organization to keep track of all the bits and pieces.  Take two days and you can get through it.  It's an excellent opportunity to go through the drive line and the body work in the rear of the bike.

I had a dodgy GPI on my K100RT and that's a bit easier to get at than on the K1100LT.

I left alone until I had other jobs in there, as in the rear main seal, clutch etc and did all at once.

You can manage fine without it BUT you also need either neutral on the clocks or clutch pulled in to run the bike, as well as a good side stand switch. Just keep your side stand switch in good order and keep a spare clutch switch. Its easy to fit. The GPI is a pain and not worth doing at the moment, a lot of money for nowt. In another 30k maybe do the full monty and do clutch etc etc and just live with it for now. I lived with a bad one on my K100RT for 50k miles and the one on my K100RS doesn't work either. I have no intention of changing it even though the bike is A1 in every other way. 


If the ignition is the problem chances are all the ABS lights and the bulb warning triangle light up.


If its the plug into the tank they don't come on like that.


If its a bad battery connection the clock also goes out.


My side stand switch on my K1100LT acted up at about the same mileage, test as said is put up on centre stand and run the engine. 


As the K1100LT is a recent buy a few things for you to look at as its an amazing bike perfect for 2 up travels:
Exhaust for cracking and crack avoidance.
Rear shock
Gas tank connector.
Side stand switch.
Screen operation
Brake fluid change and full check on brakes.
Cooling fan, check that out really well because they go faulty and the K1100 really needs it.
Valve clearances, easy enough to check even if you get someone else to do them.

On a 64K K1100LT there's a fair chance that the pivot bearings on the final drive will disintegrate when you take the final drive off. The OEM bearings use a plastic race for the needle bearings that does not hold up well.




Ted Porter has good replacements for them though:
https://www.beemershop.com/product/ei-paralever-bushing-kit-for-r80r-r100gs-r100r-k100rs-k1-k1100rslt.html

These guys do a bushing kit that I and mates have used on Paralever pivots, assuming that's a needed item when and if you get there.

Rubber Chicken Racing

Having a squiz through the various sources for this, what is an Emerald Isle product, and Ted Porter's shop does seem to have the best price going. EME, tho' I like those guys, want US$185 for the same kit Ted gets only $129 for.

Point-Seven-five wrote:K-Dawg, I don't know how much wrenching experience you have, but having a mechanic do the GPIS is going to be pretty costly.  There is easily 7-8 hours of labor in just getting to the switch and I doubt you will find a mechanic that knows more about the guts of the switch than you do.  They'll just want to replace it with a new one for about $150.

The job itself isn't all that bad, it just involves removing a lot of the back half of the bike to get at the switch and some fussing with some small springs and stuff from the insides of the switch.  The main skills you need are perseverance to stick with it and organization to keep track of all the bits and pieces.  Take two days and you can get through it.  It's an excellent opportunity to go through the drive line and the body work in the rear of the bike.

I am an amateur wrench swinger. I have found that taking the time to organize all the parts that come off is critical I have even started to use my phone for sequence of operation documentation and help me recall what bolt or thingy was where when I go back to put it all back together. 
Is it me but it seems like these bikes have so many bolt sizes, screw sizes and hexs that is incredible to keep track of what goes where. from a maintainability stand point seems like slimming down the variation of bolts and screws would be nice 

I appreciate the encouragement!
I'll take the low hanging fruit option for now and look at the first several ideas first, but I may just get in there later in the season if need be. I want to put new tires on soo maybe then?


BTW...great looking bike you have there!!

92KK 84WW Olaf wrote:I had a dodgy GPI on my K100RT and that's a bit easier to get at than on the K1100LT.

I left alone until I had other jobs in there, as in the rear main seal, clutch etc and did all at once.

You can manage fine without it BUT you also need either neutral on the clocks or clutch pulled in to run the bike, as well as a good side stand switch. Just keep your side stand switch in good order and keep a spare clutch switch. Its easy to fit. The GPI is a pain and not worth doing at the moment, a lot of money for nowt. In another 30k maybe do the full monty and do clutch etc etc and just live with it for now. I lived with a bad one on my K100RT for 50k miles and the one on my K100RS doesn't work either. I have no intention of changing it even though the bike is A1 in every other way. 


If the ignition is the problem chances are all the ABS lights and the bulb warning triangle light up.


If its the plug into the tank they don't come on like that.


If its a bad battery connection the clock also goes out.


My side stand switch on my K1100LT acted up at about the same mileage, test as said is put up on centre stand and run the engine. 


As the K1100LT is a recent buy a few things for you to look at as its an amazing bike perfect for 2 up travels:
Exhaust for cracking and crack avoidance.
Rear shock
Gas tank connector.
Side stand switch.
Screen operation
Brake fluid change and full check on brakes.
Cooling fan, check that out really well because they go faulty and the K1100 really needs it.
Valve clearances, easy enough to check even if you get someone else to do them.

92KK 84WW Olaf Thanks for feedback!


I will make a checklist of the items you suggest!
Im feeling optimistic that the side stand is the culprit but I have the time to cross check other things.

My '87 K100RS had a similar issue. It would randomly change the LCD readout of what gear I was in, not always at idle. In the end the hard plastic resin used to seal the back of the unit had broken away in chunks. I guess water was ingressed. I couldn't afford to replace it at the time (I've since located a secondhand working unit) but what I did was remove the unit whilst changing the clutch, drying it out and picking away at the broken bits until the guts were exposed. I used BMW's gasket sealant called Drei Bond, smoothing it out to replicate the original layer of hard sealant or resin. When the Drei Bond set (it never really hardens since it's anaerobic) it became a water-tight seal and the unit has worked as intended from then on - over eight years now.

Two Wheels Better wrote:My '87 K100RS had a similar issue. It would randomly change the LCD readout of what gear I was in, not always at idle. In the end the hard plastic resin used to seal the back of the unit had broken away in chunks. I guess water was ingressed. I couldn't afford to replace it at the time (I've since located a secondhand working unit) but what I did was remove the unit whilst changing the clutch, drying it out and picking away at the broken bits until the guts were exposed. I used BMW's gasket sealant called Drei Bond, smoothing it out to replicate the original layer of hard sealant or resin. When the Drei Bond set (it never really hardens since it's anaerobic) it became a water-tight seal and the unit has worked as intended from then on - over eight years now.

WOW! thats impressive!

+1 on TWB's solution for water leaking into the GPIS.  I do pretty much the same but seal it with epoxy resin.

A box of Ziploc sandwich bags and a sharpie pen is a great way to organize the fasteners and little bits when taking apart your bike.  As you disassemble something put the screws and stuff in the bag, label the bag with the Sharpie, and put the part and the bag aside.  For example, when removing the shock, put the nut and washers from the bottom, the bolt and nut from the top, the hose clamps and rubber spacers for the reservoir in the bag and write "shock" on it.  Set it aside and move on. 

Especially valuable if you are older with seriously impaired memory and may be prevented from reassembly for extended periods.  I've never had extra parts left over using this method.

Point-Seven-five wrote:+1 on TWB's solution for water leaking into the GPIS.  I do pretty much the same but seal it with epoxy resin.

A box of Ziploc sandwich bags and a sharpie pen is a great way to organize the fasteners and little bits when taking apart your bike.  As you disassemble something put the screws and stuff in the bag, label the bag with the Sharpie, and put the part and the bag aside.  For example, when removing the shock, put the nut and washers from the bottom, the bolt and nut from the top, the hose clamps and rubber spacers for the reservoir in the bag and write "shock" on it.  Set it aside and move on. 

Especially valuable if you are older with seriously impaired memory and may be prevented from reassembly for extended periods.  I've never had extra parts left over using this method.

Yesterday I was checking/adjusting valves and synchronising the TBs on my DOHC R1200RT-P. The valve adjustment is surprisingly easy considering the complexity of the twin cam in the head arrangement as compared to the old under head cam set up. Anyway, I got the plastic mostly off - impossible to do quickly with the Police model's tipover bars. When I got the bike back together, plastic and all, I discovered a vacuum cap for the right hand throttle body (the left hand side gets a hose, also left off) and two 5 x 25mm Torx head screws. Off came acres of plastic to the point of relatively easy access to the TBs, on went the cap and hose. Now, for those two screws? I never did sort out where they came from. They're much longer than the bodywork screws but shorter than the screws holding the tankbag 'rail' to the tank covers... Now where are those Ziploc bags and texter!?

Point-Seven-five wrote:
First, make sure the four pin tank connector is making good contact.  That is one of the weakest points on a K bike.

I Reread this and paused...the 4 pin tank connector? Im at work so I cant see...but I can think of the hoses and the electrical connection for the fuel level gauge...is that the four pin tank connection your talking about?

That's the one.  Hiding behind the right side battery cover.

Replace the OEM GPI screws with stainless steel Allen bolts and spring washers and use anti-seize on them. I used red Plasti-Dip to seal my GPI, red makes for faster gear changes. It lasted 20 years and I just redid it, it just needed a clean and lube. For long life it is imperative that you waterproof it with something, it is in a bad position and is subjected to water and road crap. As 75 stated the 4 pin connector supplying power to the pump is a known source of problems. Fitting a 4 pin waterproof is a good choice.
Regards Martin.

welp. I tinkered on the bike.
1.) played with the kickstand a bit, fired engine up, "jimmied" with the stand and not much I can tell made a difference. The Engine idle seemed normal and when I played with kickstand either it died or stayed on... no janky putter out in idle. sorta a binary response.
2.) pulled the tank sensor underneath and it actually felt tight and snug very clean on the 4 pin connections. I decided to ride just a bit let the wire hang and flop in the air and no choppy idle.
3.) I wasnt successful getting the key/ignition out and take a peak at the wiring (will get on that next)

I did notice (funny when you start paying attention to things) that every time I come to a stop, I down shift and it seems to not want me to get into 1st gear until I am almost at a complete stop or going 5mph before I can find 1st gear... is that normal?


I want to say thanks everyone for posting me you help! its greatly appreciated!


MartinW....is this something easily done? replacing GPI screws? 
Im becoming more fixated on the gearing at this point.

K-dawg wrote:I did notice (funny when you start paying attention to things) that every time I come to a stop, I down shift and it seems to not want me to get into 1st gear until I am almost at a complete stop or going 5mph before I can find 1st gear... is that normal?

"They all do that."

duck wrote:

K-dawg wrote:I did notice (funny when you start paying attention to things) that every time I come to a stop, I down shift and it seems to not want me to get into 1st gear until I am almost at a complete stop or going 5mph before I can find 1st gear... is that normal?

"They all do that."

"They all do that"!! wriggly toes help 

Double clutch with a throttle blip helps.

Dawg the screws can only be accessed with the swinging arm removed and is a job you need to do when servicing or changing the GPI. Even if replacing the GPI with a new one it is prudent to waterproof the new one. After waterproofing mine with Plasti Dip 20 years ago when I serviced it a few months ago the OEM cover was fine. There are heaps of products capable of doing the waterproof job. The first OEM cover on my original switch had degraded after 6 years without the additional protection.
Regards Martin