1990 K75 will not run more then 52 miles!

[CNRED]

I have trailered this bike more miles then I have riden it.
It has stoppd running twice, both times about 10 miles from home, very annoying.
The sernerio goes like this:
   Rode the bike bout 30 miles to a bike shop to pick up a few parts for anpther bike.  Parked the bike in the parking lot for about 45 minutes.  Came out got on and it started immediately and ran impecabilly for about 25 miles at which point the motor quit while going about 40 MPH.  Got to the side of the rode but the bike would not start.  Got a ride home and returned with my trailer.  When I got to the bike it still would not start.  I opened the fuel cap to see if there was any pressure either positive or negative, there was none. tried to start it again, no joy.  I trailered the bike home and put it in the garage.  The next morning It started perfectly and ran excellently.
   I thought I might have a fuel pump problem so I drained the tank and puled the pump.  The vibration damper inside the tank was disintegrating and there was bits of rubber all through the tank and the pump screen was missing.  It appears a previous owner had replaced the pump at some point and did not feel it important enough to replace either the desinigrating damper or to replace the pump screen.  At this point I feel I have found my problem.  I ordered a new fuel pump, tank damper, pump screen, fuel filter and three foot of submersible fuel line.  I put it together, test rode it about 10 miles seemed fine.
   About a week alter I rode about 20 miles to a friend's house where we replaced the brake fluid front and rear.  The bike sat for about two hours.  Got on the bike to ride home and about 10 miles into the return trip, while sitting at a stop light, the bike quit and would not re-start.  I pushed it out of traffic, called a friend to come and get me.  I tried to start it several times, it would crank, and try to start but could not stay runing. It took about an hour for my friend to get to me.  We tried to start  the bike again and it started, ran for about four blocks and quit again.
When we tried to re-start the bike again, it sounded like it wanted to start but was starving for fuel.
Went home, got the trailer again.  Returned to the bike I tried to start it again but it would not start.  It was not even attempting tp start at this point.  Went out to the garage the next morning, it starts and runs fine.  Ran it around the block a few times, (don't want to get too far from home) ran fine, sounds great.
   Each time the bike quit, it was after being parked for a short period of time, then ridden.  The outside temp was in the high 80's, clesr snd dry. (Ironically, great riding weather).
   I did some reading and I found that some of these bike have a problem with the Hall Electronic Sensor, and bikes with this problem exhibit symptoms alot like mine.  One of the tests for a faulty HES was to remove the HES plate in the front of the motor. Start the engine let it warm up and use a hair dryer to put heat on the HES.  If the Motor stops, most likely you have solved the problem. 
I did the above, the motor was a operating temp and I heated the HES for about 5 minutes with a hair dryer.  The bike kept running, it even went through several fan cycles as well.
   This bike is new to me and has just over 32K on the clock.  I believe the mileage to be correct, the bike is in very nice condition and appears to have been taken care of in the past.  I also believe that the mileage is low because no one has been able to solve this problem.  The past two owners put only 300 miles on the bike.
   Even though this is not my primary go to bike,  I'd like to get this thing sorted out, any help will be appreciated.  I'm not sure where to look next.
   I do all my own work, but I am not a wiz when it come s to electronics, but I can follow directions.
     Thanks

[johnny]

greetings...

classic 4 pin...

#3 here...

http://www.motobrick.com/index.php/board,9.0.html

j o

[rbm]

Read up on Hall sensors.  I think this might be your problem (assuming that the fuel tank connector problemthat Johnny just pointed out doesn't fix it).

Diagnosis consists of starting the bike cold and, while idling, heat the hall sensor with a hair drier (need to remove the timing cover on the front of the engine to get access to the Hall sensors).  If the bike dies, problem found.  If you feel so inclined, you can build a homemade BMW ignition diagnosing tool by following these instructions.

There are instructions for the above diagnosis on IBMWR site and on this site.  Common remedy is to purchase the raw sensors off Ebay and replace the failing ones on the stock carrier.  Much cheaper than sourcing a complete OEM unit new or taking a chance on a used one (with the risk of having the same problem).

Question though:  When you were on the side of the road trying to start the bike, did you hear the fuel pump running on for 1.5 seconds AFTER you released the start button?

[Laitch]

Robert and johnny have both indicated classic diagnostic steps for sorting this problem. If following through on their recommendations doesn't change the condition, consider the following.

If the fuel pump damper ring had disintegrated then your fuel lines, fuel rail and fuel injectors may be clogging with the fine particle residue of that disintegration. When the bike is idle the particles settle; when it is in motion they circulate and clog. You should consider checking the spray pattern of the injectors and change the fuel lines. You should consider checking all rubber components including the crankcase breather and the rubber throttle body manifolds.

Idleness effects these bikes. Electrical switch plugs and the switches themselves corrode. Long-term storage with gasohol can harm the fuel system. In bikes that don't see regular use, fuel should be conditioned with Sta-Bil and the fuel used or replaced within one year, according to my experience.

[CNRED]

greetings...

classic 4 pin...

j o

Johnny,
   I thought I had that connector pretty clean when I cleaned the tank and replaced the pump, filter and damper.
   I'll revisit and clean it again as recommended.

rbm wrote -
[size=0px]Read up on Hall sensors.  I think this might be your problem (assuming that the fuel tank connector problemthat Johnny just pointed out doesn't fix it).[/size][/size][size=0px]Question though:  When you were on the side of the road trying to start the bike, did you hear the fuel pump running on for 1.5 seconds AFTER you released the start button?


[/size]RBM   I tried to get the bike to quit using a hair drier, but it was fully warmed up.  I'll try when it is relatively cold and see what happens.  I thought, in as much as the problem only occures when the bike is hot that the test should be done when it was at operating temp.[size=0px]
[/size]   I agree that it acts like a HES but they are costly, I would like to be sure it is failing be fore I replace.[size=0px]
[/size]   I did not notice if the pump was working or not.  Most of the time I don't hear it even when the bike is running properly.[size=0px]

[/size]Laitch wrote -[size=0px]
Robert and johnny have both indicated classic diagnostic steps for sorting this problem. If following through on their recommendations doesn't change the condition, consider the following.If the fuel pump damper ring had disintegrated then your fuel lines, fuel rail and fuel injectors may be clogging with the fine particle residue of that disintegration. When the bike is idle the particles settle; when it is in motion they circulate and clog. You should consider checking the spray pattern of the injectors and change the fuel lines. You should consider checking all rubber components including the crankcase breather and the rubber throttle body manifolds.Idleness effects these bikes. Electrical switch plugs and the switches themselves corrode. Long-term storage with gasohol can harm the fuel system. In bikes that don't see regular use, fuel should be conditioned with Sta-Bil and the fuel used or replaced within one year, according to my experience.


[/size]Laitch,[size=0px]
[/size]   I thought about fuel contamination from the damper, but dismissed it thinking the filter the previous owner installed when he did his fuel pump replacement would have caught the particulates before they got into the fuel system.  Now, I'm thinking I may have been a bit short sighted.  The bike was most likely misbehaving prior to his pump replacement.  The possibility exists that the damper particles may have already been sucked into the system.  Two fuel pumps later it is still doing the same thing.[size=0px]
[/size]   I guess I'll get out the shop manual and clean the system. [size=0px]

[/size]Thanks to those who responded, I'll keep you posted as I progress.  [size=0px]
[/size]It's frustrating when there is a problem such as this that can't be duplicated in the shop for remedy. [size=0px]
[/size]I thought the pump and damper issued was the "smoking gun" but I was wrong.  The good part is that when I do find this problem I will know exactly what this bike is all about.  [size=0px][/size]

[kris]

CNRED, don't give up on this bike. It is certainly not her fault that the P/O didn't treat her right. Believe us all when we see "you'll be glad you stuck it out". Once running right you will have a stupid ear-to-ear grin for thousands of miles whilst enjoying admiring looks from those who know (but don't admire too much...keep your damn eyes on the road!)


I found it helps if you speak sternly to her in German whilst wrenching!

[CNRED]

I certainly will not give up.  It's great bike, runs excellently when it runs.  Just a situation that is difficult to source.

[rbm]

RBM   I tried to get the bike to quit using a hair drier, but it was fully warmed up.  I'll try when it is relatively cold and see what happens.  I thought, inasmuch as the problem only occurs when the bike is hot that the test should be done when it was at operating temp.
I agree that it acts like a HES but they are costly, I would like to be sure it is failing be fore I replace.
I did not notice if the pump was working or not.  Most of the time I don't hear it even when the bike is running properly.

The hairdryer trick is to simulate a fully warmed up bike but without fully warming up the bike.  Spark timing problems occur when a defective HES is temperature stressed and you are stimulating this condition, thus confirming the part is broken so that you don't go through the costly parts replacement exercise.


Most owners, including myself, can't hear the pump running while the engine is cranking or firing.  But most can hear it once the cranking or firing stops.  The pump run-on is important to notice as it gives you clues to where your problem may lie.  If you didn't hear the pump run-on, then Johnny's or Laitch's diagnoses could be correct.  If you did hear it run-on, then you can discount Johnny's diagnosis but Laitch's may still be valid.

[Laitch]

   I.    -Laitch,      I guess I'll get out the shop manual and clean the system.  

How about previewing your post before you actually post and cleaning up that mess? Reading it is like listening to somebody talking and hiccuping at the same time. Of course, you're not forcing anybody to read it. They have to force themselves. :giggles

What johnny said.  :2thumbup:

[rbm]

The forum software does really weird formatting tricks when copying/pasting Laitch.  Can't really blame the poster.  It is possible, though, to go back into a whacky posting and delete all the weirdness the software put in.  Like Johnny suggested, click on the "Toggle View" button just above the emoticon playing the violin to see the whack.

[Laitch]

The forum software does really weird formatting tricks when copying/pasting Laitch. 

It hasn't done anything I could not catch in Preview when my vision wasn't blurred by emotion, rbm. :giggles

[Laitch]

none of this whack was happening before we enable the wysiwyg...

There was all the other bike-whack, thought-whack, expression-whack. Where I come from there's a saying. Whack is whack. Deal with it. Then ask Bernie Sanders to fix it.

[johnny]

greetings...

just gotts off the tele with debbie wassman and donnie brazille... they are gonna have john podesta ping bernie to  disable the WYSIWYG editor...

j o

[CNRED]

I'd be happy to edit the post, if I knew how.

[Motorhobo]

It seems new posters have some problems getting the tags to display properly. I wouldn't worry too much about it. Either you'll figure it out or the software will fix itself once you have a certain number of posts. Keep posting and damn the torpedoes.

[Martin]

There are small filter screen fitted into the inlet of the injectors that are often overlooked. They can be removed by screwing in the appropriate self tapping or sheet screw and pulling out with vice grips. the fuel rail  and external hoses needs to be checked as well. If the HES is at fault the components can be purchased and changed at a lot cheaper cost than replacing with new or second hand parts.
Regards Martin.

[Al]

I also posted this in reply to another post:

My 1990 K75 did a die and live again routine on me. When the bike was hot-especially if was heat soaked after a ride- it would run about 2-5 minutes and then cut out. Let it sit a few minutes and it would run fine until the next time. Sometimes it would do it a couple time in a month and other times i would happen several times a day. At the Billings rally it died completely. WOuldn't start first thin in the morning. I had suspected the Hall sensor so I bought 4 of them for $36 from a Chinese lady in Germany. As opposed to $500 from BMW. It has been running fine ever since. I now carry the 2 spare with me just in case. I also picked up a burned out unit so that I can just do the old switcher instead of soldering it on the road.Oh, except one  or two incidents when it died after sitting. I was immediately thinking it was the Hall sensors but turned out to be the kill switch. The plastic shaft develops a ring worn on it which prevents it from sliding down into the contacts. On the MOA site someone showed how he took some very fine sand paper and smoother that ring away resulting in no problems henceforth. I'm not impressed with eh quality of BMW K bike switches, The seem kind of mickey mouse to me.Not sure if any of these help but maybe someone will get some use from the info.

[CNRED]

Al,
Thanks for the post.  The more I work on this bike the more I feel ithe HES is the problem.  I'm going to see if I can make it fail this morning with a hair dryer.  Just to be sure, I'll clean the fuel system as well.  This is a bike I bought to replace a bike that I used for long distance touring.  I've had a bunch of BMW's mostly "F" and "R" GS bikes, my first "K" bike.  I'm sure once I find the problem this will be an excellent touring machine.

[Motorhobo]

I also posted this in reply to another post:
I was immediately thinking it was the Hall sensors but turned out to be the kill switch. The plastic shaft develops a ring worn on it which prevents it from sliding down into the contacts. On the MOA site someone showed how he took some very fine sand paper and smoother that ring away resulting in no problems henceforth. I'm not impressed with eh quality of BMW K bike switches, The seem kind of mickey mouse to me.Not sure if any of these help but maybe someone will get some use from the info.

I also has exactly the same issue with the start button -- I think the electrical contacts inside the combo switches are a hugely underrated cause of problems. For me, it was with a bike that has seen a lot of Seattle rain from the time I acquired it in 2000 to the time the corrosion in there started interfering with the contact in 2009. So that's 10 years of neglect -- which is probably a lot better than a Mickey Mousey switch would have fared. So -- not sure I agree with the quality assessment -- you have to do the maintenance on 20+ year old stuff, and those switches are parts that never see the light of day so people assume they're bulletproof -- they're not.

Anyway, I ended up tearing the thing apart trying to bridge past the start button so I could at least push-start it (it was a sidecar rig). The switch was destroyed but I was able to push start it avoiding a costly tow. I got a new used combo switch from kbikeparts.com, no problem since, and I don't live in Seattle anymore so less rain gets in there...

[Filmcamera]

I have an intermittent issue with my starter button as well.  Once in a while I hit the button and nothing happens  a quick turn of the handlebars full range left and right fixes it.  I assume that there is a weak or loose connection somewhere in the right hand combo switch wiring. I will get to it soon - probably the day after it leaves me stranded!

[Motorhobo]

Don't wait -- it's not like if the starter button fails, just the starter fails -- everything fails. I had that symptom and waited and got stuck on I-76 in Philly -- had to turn the rig around and push it downhill against the flow of 75mph traffic on the shoulder in blazing heat...sucked. What's worse, the dog was in the car and I was more worried about him than me. Don't let it happen to you...with or without dog...

[Filmcamera]

OK so you think it is probably somewhere in the right hand combo switch connections?

I did notice after my test ride the other day the bike very slightly hesitated as I pushed the handles bars through their full range, close to but not quite at the far end of travel both left and right side.

[Motorhobo]

OK so you think it is probably somewhere in the right hand combo switch connections?

I did notice after my test ride the other day the bike very slightly hesitated as I pushed the handles bars through their full range, close to but not quite at the far end of travel both left and right side.

If you're talking about the 'nothing happens when you push the start button' issue -- all I can say is what I experienced, i.e. The button worked, then sometimes didn't work, then sometimes did work, then failed, and when it failed the bike had no power. If you are in the 'sometimes didn't work' stage, I'd address it before it gets to the 'sometimes works' stage, because one stage beyond that sucks big time.


There's a switch rebuild thread here somewhere I think -- can't remember details. I'd read up on it before trying to disassemble the switch though -- I remember there being very tiny parts involved...

[jaxon]

So it goes twice the distance of a Harley rider and you're complaining?  :eek:

[Filmcamera]

If you're talking about the 'nothing happens when you push the start button' issue -- all I can say is what I experienced, i.e. The button worked, then sometimes didn't work, then sometimes did work, then failed, and when it failed the bike had no power. If you are in the 'sometimes didn't work' stage, I'd address it before it gets to the 'sometimes works' stage, because one stage beyond that sucks big time.

Hmm I am not sure it is the switch itself - if the starter button does nothing all I have to do is move the handlebars all the way to the left and then back and the button works again. I think it is maybe a slightly bad connection somewhere in the hell that is all the loom connections under the tank. I never lose the rest of the electrical connections, the pump is primed all the lights are on etc it is just pressing the button does nothing until I move the handlebars.  Anyway I will take you advice and dig into it to find out what is going on - as you rightly say it if I do not it is bound to fail at the worst possible time.

Ok enough - apologies for the thread jacking!