Post by: CNRED on May 19, 2017, 04:52:44 PM
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
Post by: johnny on May 19, 2017, 05:14:18 PM
classic 4 pin...
#3 here...
http://www.motobrick.com/index.php/board,9.0.html
j o
Post by: rbm on May 19, 2017, 05:18:20 PM
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 (http://www.k100-forum.com/t5192-homemade-multifunction-ignition-timing-abs-code-reader-injectors-tester).
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?
Post by: Laitch on May 19, 2017, 07:09:59 PM
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.
Post by: CNRED on May 21, 2017, 07:32:42 AM
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]
Post by: kris on May 21, 2017, 08:31:09 AM
I found it helps if you speak sternly to her in German whilst wrenching!
Post by: CNRED on May 21, 2017, 08:42:00 AM
Post by: rbm on May 21, 2017, 08:42:55 AM
Quote from: CNRED
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.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.
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.
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.
Post by: Laitch on May 21, 2017, 08:49:34 AM
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
I. -Laitch, I guess I'll get out the shop manual and clean the system.
What johnny said. :2thumbup:
Post by: rbm on May 21, 2017, 08:54:54 AM
Post by: Laitch on May 21, 2017, 09:01:50 AM
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
Post by: Laitch on May 21, 2017, 09:11:04 AM
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.
Post by: johnny on May 21, 2017, 09:13:56 AM
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
Post by: CNRED on May 21, 2017, 02:16:19 PM
Post by: Motorhobo on May 21, 2017, 03:21:19 PM
Post by: Martin on May 21, 2017, 03:34:29 PM
Regards Martin.
Post by: Al on May 23, 2017, 11:00:12 AM
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.
Post by: CNRED on May 23, 2017, 11:10:16 AM
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.
Post by: Motorhobo on May 23, 2017, 12:12:40 PM
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...
Post by: Filmcamera on May 23, 2017, 01:08:04 PM
Post by: Motorhobo on May 23, 2017, 01:41:38 PM
Post by: Filmcamera on May 23, 2017, 02:12:38 PM
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.
Post by: Motorhobo on May 23, 2017, 04:15:07 PM
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...
Post by: jaxon on May 23, 2017, 04:23:11 PM
Post by: Filmcamera on May 23, 2017, 05:09:15 PM
Quote
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!
Post by: Al on May 23, 2017, 06:30:01 PM
Post by: Andy FitzGibbon on May 23, 2017, 06:37:51 PM
Andy
Post by: CNRED on May 23, 2017, 06:38:10 PM
I was in the garage today with a hair dryer trying to get the HES to fail.
I pulled the HES cover, started the bike let it idle on "Choke" until it idled on it's own. Applied the hair dryer all up until the bike's fan came on. At that point I felt I was looking in the wrong place. I let the bike sit for about an hour and gave it another shot with the dryer. Again I kept the dryer on the HES until the cooling fan came on. I felt I was "barking up thre wrong tree" so I let the bike idle, shut off the dryer and replaced the HES cover. About 30 seconds later the bike sputtered and quit, would not restart. Starter turned the motor over, sounded like it wanted to start but was not getting any fuel. There was no fuel pump run-on after letting go of the starter button. I pulled the 4-pin connector under the seat, no power at any of the connections with the key on. Waited an hour, still no power at the 4-pin.
My question is, what interrupts the power to the fuel pump when the motor is hot?
Post by: Laitch on May 23, 2017, 07:03:40 PM
My question is, what interrupts the power to the fuel pump when the motor is hot?One reason might be that as aging friction fittings like pin connectors and fuse terminals expand from heat, the mating connections can lose ufficient effective contact. If they are oxidized that will happen sooner than later. Same can happen with a slightly—almost imperceptibly—loose ground connection.
Pull your fuel pump fuse, clean its spade connections and its receivers with emery cloth–replace it if you've got a spare. Clean your fuel pump plug pins and sockets even if you did that previously and see how tightly together they assemble. Same goes for the ignition switch plug under the tank. Clean your Jetronic main plug and be sure you can hear a click when you reengage it. Plugs should fit tightly and take some effort to separate—not hernia-producing effort though. Grunting shouldn't be needed, but they shouldn't just slip apart easily.
This is all stuff you should do with a used K-bike newly purchased—detail work. If that doesn't change the condition, you're ready to look elsewhere.
Post by: rbm on May 23, 2017, 07:45:54 PM
There's no safety circuit or cutout that disables power to the engine when warm. If you didn't hear pump run on or measure +12V at the Green/white contact on the pump connector (relative to ground), then your problem is further upstream. That possibly means connection problems with Fuse 6, possible connection problems with the fuel injection relay, possible problems with connections at Fuse 1, possible problems with connections in the kill switch or possible connection problems with the ICU under the tank near the headset. Concentrate on cleaning those contacts with Deoxit if you haven't already done so. Laitch's advice about poor contact at the fuel tank connector is especially relevant since that is a known weak point with the electrics. It would behove you to replace that connector with a more reliable one at some point. I would suggest a AMP SuperSeal connector since that has moisture protection built in. These connectors are very common on Japanese and European cars nowadays and can be bought online or hoarded from the junkyard.
Post by: CNRED on May 23, 2017, 08:05:08 PM
I believe I'm going to have to go conection by connection.
When the bike quit, there was no fuel pump run on, no power at the 4-pin, and no power across the 7.5 amp, fuse #6 with the key on. There was power at the green and white wire in the 4-pin, but only when the starter button is depressed. Power goes away when the button is released. The brown wire in the 4-pin appears to be providing good ground.
I'm going to check the 4-pin and the #6 fuse in the morning to see if there is power.
I cleaned the 4-pin when I changed the fuel pump but I'll re-visit. The Jet-Tronic connection is clean, I have two units, I swapped them the last time the bike quit on the road, didn't seem to have any effect.
I'm going to work my way foward from the fuse box and see what develops.
Post by: Elipten on May 23, 2017, 10:15:34 PM
Sent from my iPad using Tapatalk Pro
Post by: CNRED on May 24, 2017, 01:22:16 AM
I just bought a can of Deoxit.
I'm going to go back to the connections I have already cleaned and clean them again with the Deoxit just to be sure.
Post by: CNRED on May 24, 2017, 01:25:55 AM
Just a quick note. On the MOA site there is an archived piece on how to take the switches apart to clean them. Good pix and instructions. Easy enough to do part from taking the tank off which isn't as formidable as it first seems. All the best beating your gremlins.
Al could you send me the link to this MOA piece, I'm sure I will need it. Thanks
Post by: CNRED on June 02, 2017, 10:14:02 AM
The good part is the #6 fuse is dead on both sides with the key on, as is the fuse holder, I guess that would also be the the bad part. The bike will crank, but obviously with no p[ower to the fuel pump, will not start.
Maybe it will be easier to find the problem now that I have a problem I can actually see.
Going to pull the tank and fairings today and start checking wiring, connectors, and relays.
Post by: Martin on June 02, 2017, 06:21:16 PM
At least you have found a starting point, which is a lot better than finding nothing. Keep at it you will be rewarded. :2thumbup:
Regards Martin.
Post by: rbm on June 02, 2017, 06:28:31 PM
- check the power to the FI relay on Red. Always on 12V, doesn't matter where the key or kill switch are
- Reseat the ICU connector a couple times after cleaning it with Deoxit
- check power from the FI relay on Green/Red (either) with the key on and kill switch in normal. If none, check the following
- check power at Fuse 1 on Green/Yellow with the key on and kill switch in normal. If none, then problem is further upstream.
That's enough for now. Get back with your findings
Post by: CNRED on June 02, 2017, 07:20:19 PM
I have power to the red wire with the key off and the key on. Withn the key on I also have power to the Green/Yellow wire as well, but no power to the two Green and red wires, and obviously still no power to the fuse. All the rest of the fuses have power with the key on.
I pulled the relay and connected power to the male red prong and power to the green/yellow male prong. I then grounded the male yellow/brown prong. I then used a test light and found power at the both the green and red male prongs of the relay.
I'm wondering if the ground to the relay supplied by the yellow/brown wire is good.
At this point I had to stop, the boss (Wife) wanted to go out to eat.
To be continued...
Post by: rbm on June 02, 2017, 07:26:18 PM
1. First test the relay outside of the circuit with a meter to see that it is functional. Coil should have 50 ohms resistance or so; open circuit means the coil is bad. Apply +12v across the coil and test for continuity between Pin 30 and each of the Pin 87 - there are two. If contacts are bad, relay needs to be replaced.
2. If all checks out, then the culprit is now pointing to the start circuitry. The Green/Yellow to the FI relay comes from the kill switch, which gets its power from the ignition switch. Test voltage on the Green wire going to the kill switch. With the kill switch in the normal position, if there is power on Green with the ignition on but none on the Green/yellow, the kill switch is the culprit.
3. If there is no power to the Green wire with the ignition on, the ignition switch is the culprit.
Power to the Yellow/Brown really only comes when the start button is pressed so what you are seeing up to this point is somewhat normal.
Read Bert's page on EFI troubleshooting (http://k-bike-knowledge.000webhostapp.com/electrical/EFI/bike-wont-start-EN.htm), especially the section entitled "what happens when you press the start button".
Post by: CNRED on June 02, 2017, 08:16:14 PM
Ill take a look Sunday when I can get back to it.
Thanks for the info on the Yelow/brown, I believe I would have been chaseing my tail.
Post by: CNRED on July 26, 2017, 02:57:30 PM
Been awhile since I updated this thread.
A little review, 1990 K75rt would quit after 45 to 50 miles would not restart until it completely cooled down, got to ride in the trailer on a couple of occasions.
I replaced everything in the fuel tank, (Pump, Pump Damper,Filter and submersible fuel line) still no joy.
rbm checked most all of my electrical connections and helped me change the four pin connector, I thought we had it fixed until the next morning, it would not start.
A few messages back and forth with rbm, and we felt it might be the fuel sender in the fuel tank. I emptied and pulled the tank and removed the sender. Long story short, ione of the wires that goes through the seal at the bottom of the tank was not holding continuity. If I clipped my multi-meter to the wire that was supposed to be inside the tank and the clipped the other multi-meter lead to the wire on the out side of the tank would get continuity, if i applied a little pressure to the sollder joint where the wire goes through the seal I would loose continuity.
I ordered a new fuel sender, (very pricey) installed it and the tank on to the bike. It started and ran. It's been very hot here on Phoenix, so up until to day I had not had a chance to ride the bike to see if the situation had been resolved.
Today, I hooked up my trailer to the back of my truck put on my helnrt and took off. Rode for about 30 miles turned the bike off to let it "heat soak" for about 15 minutes. Got back on rode another 30 miles with out incident and without the trailer to get me home. The bike ran excellently.
It might be a bit premature, but I believe the problem has been taken care of.
Thanks to everyone that responed top the thread and for all of the advise.
Special thanks to rbm for taking time from his busy Phoenix schedule to come and help me source this problem.
Post by: John Lang on July 26, 2017, 08:14:02 PM
Post by: Laitch on July 26, 2017, 09:13:42 PM
I get lost in the maze trying to follow the wiring diagram relating to the fuel level sensor. How does it affect anything other than the low fuel warning light?The current that controls the fuel pump comes from its attachment to the sensor. Damage to certain wires coming through the tank from the 4-pin connector will shut down the pump, shut down the sensor or shut down both. This diagram is from a pre-1990 K75 but it shows the connection between the sensor and the pump.
Fuel pump and fuel sensor wires pre-1990 K75.png (112.87 kB . 398x352 - viewed 435 times)Maybe CNRED will disclose to us the color of the wire—or wires—that were faulty. That might be helpful.
Post by: rbm on July 27, 2017, 05:08:21 AM
Post by: Laitch on July 27, 2017, 05:12:35 AM
Post by: John Lang on July 27, 2017, 09:02:20 AM