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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: dfx on November 09, 2015, 01:05:32 PM
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Help, I just broke down again for the third time in about 3 outings since July. I'm really sick of pushing this bike. Anyhow, coming home on a roundabout, the engine just died. Thought i was low on fuel so pushed it to a petrol station. Can no longer hear the fuel pump when I push the starter switch. The first breakdown was due to a holed tank which I repaired only to break down 5 miles later because of (apparently) a torn bushing between plenum chamber and injectors. I replaced all the bushings and the bike was running fine. However, the red fuel warning light has always played up since. I wonder if this warning light has another reason for coming on, ie to indicate fuel pump problems? I say this because coming home the orange light came on then the red one almost immediately. I used the odometer to determine how much fuel is left so I shouldn't have been running low.
I have to go and drive with some tools to try and fix the bike tomorrow (if it's still there) so if anyone could give me some clues I'd be grateful. Apart from the connector to the pump at the front left of the tank, what else should I suspect? Is there a fuse? Thanks.
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What year? It sounds like it could be the connector for the pump and level sender on the right side behind the side cover. Those have been known to go bad. A decent fix is to replace the connector with a flat 4-pin trailer lights connector.
Tom
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It's a 1985 k100rt
I was reading this thread, http://www.motobrick.com/index.php/topic,7490.0.html (http://www.motobrick.com/index.php/topic,7490.0.html)I think it concerns the connection directly under the fuel tank at the left near the fuel hose. Is the connector you mention at the other end of these wires? The one here? http://www.motobrick.com/index.php/topic,7480.0.html (http://www.motobrick.com/index.php/topic,7480.0.html)
Thanks
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I have the wiring diagrams but the quality is not good. I think the colours of these wires have changed.
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greetings dfx...
thats the one...
pull your right side cover off... you should see it...
http://www.motobrick.com/index.php/topic,7480.0.html
j o
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Hi, I had a quick look on the way home and didn't see a connector like that. Mine's a 1985 model I think it's changed somewhat. Off tomorrow with enough tools to get the tank off and a voltmeter to try again.
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I was reading this thread, http://www.motobrick.com/index.php/topic,7490.0.html (http://www.motobrick.com/index.php/topic,7490.0.html)I think it concerns the connection directly under the fuel tank at the left near the fuel hose.
This connector is on the right side of the bike.
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I believe that both links you included pertain to the connector on the right side behind the side cover. The one that Johnny shows in his picture.
I have never worked on an '85 so it might be a bit different. But I do suspect that connector as the culprit.
Tom
It's a 1985 k100rt
I was reading this thread, http://www.motobrick.com/index.php/topic,7490.0.html (http://www.motobrick.com/index.php/topic,7490.0.html)I think it concerns the connection directly under the fuel tank at the left near the fuel hose. Is the connector you mention at the other end of these wires? The one here? http://www.motobrick.com/index.php/topic,7480.0.html (http://www.motobrick.com/index.php/topic,7480.0.html)
Thanks
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Here's my connector, I think it must be the white one. (http://eschbachfc.free.fr/wp-content/uploads/PICT00351.jpg)
Did the cleaning bit with the toothbrush but none of that there how you say yee ha. So looked at the fuse which was broken. Changed the fuse, but still nothing. Strange no? Measured 10V at the pump connector under the tank at the left:
(http://eschbachfc.free.fr/wp-content/uploads/PICT0036.jpg)
So measured the resistance of the pump : 0 ohms!! So obviously the fuse blew, but why didn't it blow again as soon as I replaced it?
(http://eschbachfc.free.fr/wp-content/uploads/PICT0037.jpg)
Next step is to test the pump outside the tank. This is what it looked like a couple of months ago when I had to fix a leak in my tank. Looks like some overheating been going on there.
(http://eschbachfc.free.fr/wp-content/uploads/PICT0039.jpg)
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When I returned to my bike to try and fix it, I suddenly realised I had definitely not left her it in a safe place. I had not noticed a trashed Alfa Romeo when I left her the night before. Perhaps it had happened that night and those that did it thought that my bike had already been trashed :hehehe. But I couldn't leave her a third night and I'd had enough of paying people to tow it home for me.
(http://eschbachfc.free.fr/wp-content/uploads/PICT0038.jpg)
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So for the price of a couple of K100 fuel pumps I found this. I never once drove a car with a trailor on it. Yeee Ha!!! :clap:
(http://eschbachfc.free.fr/wp-content/uploads/PICT00391.jpg)
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Nice trailer find! Clist?
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Craigslist? No, that doesn't seem to work yet here. I'm in France!
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Le craigslist?
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I don't mean to get off topic, but my condolences on the loss of your countrymen today.
Tom
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Thanks, I'm not directly affected but we're all shocked of course. I hope you won't think I'm callous, but it didn't stop me taking out my fuel pump as I'd planned, so I'll get back to the topic. Lifet goes on.
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Got the pump off and measured around 3 ohms across the terminals although as I said before, at the connector I had 0. So I hooked it up to a battery and it made a little clunk each time but wouldn't turn. I suppose there's nothing that can be done so I was looking at a replacement. The Bosch unit is around 170€ but I found this for neary half the price http://www.ebay.fr/itm/Pompe-a-essence-BMW-K75-K100-LT-RS-K1100LT-K1100-16121461576-0580463999-HQ-52mm-/321564774804 (http://www.ebay.fr/itm/Pompe-a-essence-BMW-K75-K100-LT-RS-K1100LT-K1100-16121461576-0580463999-HQ-52mm-/321564774804) wondered if anyone else had tried a replacement part? This one has a 3 year garantie on it which seems strange.
My unit has "made in Germany " on it so it can't be the first pump the bike has had - it would have been West Germany. So how long do these things last?
And I also wondered : ae there any other parts on this model that have the same tendance to just die on you and leave you in a potentially dangerous situation?
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Actually these pumps are fairly reliable, its lasted 30 yrs already. What takes them out are -letting the bike sit-running the tank low on fuel. Ride the bike regularly, keep the tank above a half and you will get long life out of the pump. Search "fuel pump" on this site and you should come up with either a lower cost solution or substitution. My bike has 75K on the original pump.
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It is the gasoline these days. The old pumps were not built to handle the garbage sold as Gas now days. Also it is well known you need to run it a little every week or so. Long term storage with water also accumulating in the tank leads to failure. Buddy replaced with cheap copy off eBay last year. It worked but he just has not rode it much.
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+1 to Tuco and Elipten.
Fuel pump well-being and longevity seem to be connected to fuel, miles and maintenance. A pump that runs often, within plenty of clean fuel, with its filters inspected, and with its hoses in good shape likely will run longer than one that is pumping through partially obstructed filters and lines within a half-filled tank of stale fuel for short distances. My bike is a 1995 with 50k miles. It appears to have its original pump. Its filters have been replaced. I have the pump's after-market replacement standing by.
I think what's more likely to cause a K engine to "just die" will be an electrical connection. My bike "just died" two days after I bought it. I was on a lightly traveled rural gravel road. The bike just shut down right there. I really didn't know its operating system, I bought it just because liked how it felt to ride. I checked the fuel level in the tank. I started an electrical check. I checked the fuses and battery connections but then I discovered the ECU plug—obviously a critical component although damned if I knew why. Its problem wasn't obvious though; the plug wasn't hanging loosely. It was just that its latch tab—once I found it by looking through the handbook—had no tension.
Apparently, when the battery had been reinstalled that April, the ECU plug hadn't been latched securely after its holder had been installed the frame. The plug had started backing off its connection while I was pounding over the road's rills and gullies. When it loosened sufficiently, the show stopped right there, next to the river. I pushed it firmly into its connector, pushed the latch closed, pulled on the plug to be sure it was secure then away I went. Later I pried the spring steel latch to give it more closing tension—no failure since then.
So there's the ECU plug, and the instrument panel main plug and the right-side four-pin connector to be certain connections are relatively clean and tight; the ignition switch, too. Failures with any of them can be show stoppers—not necessarily dead at once but stumbling, twitching, coughing, starting and stopping until you've torn out all your hair and wind up riding the bike on a trailer while somebody tows you around for sightseeing.
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+1 on that four pin connector that says "TANK". Make very sure the connections inside are clean. I had my K100RS stop dead twice on me within the first 10 miles I had because of that connector. Sprayed DeOxit in there and have had no problems since. In fact, I keep the DeOxit on my workbench and make a habit of shooting every electrical connection I come across with it followed by a smear of Dow Corning dielectric grease.
One other electrical component that can give you fits is the ignition key switch. After about 20 years and 60,000 miles even if the bike has been garaged for all it's life they can give you some strange intermittent electrical problems. It might be a good idea to do some preemptive cleaning if you have the opportunity.
http://www.eilenberger.net/K75S/IgnitionSwitch/
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The 85 is different from the next models in fuel pump elect. the plug is on the left side in front portion of gas tank, hooks to the 4 male plug, that is upside down. Problem I had with my 85 was not the connection or the pump, but rather the female connections were worn down and the plug slipped off the tank portion. I used a pick and "re-sized" the female ends ever so slightly to tighten the connection and never had any more troubles.
The thing that fails on fuel pump is usually not the pump, but rather the rubber isolator that surrounds the pump, causing the filter to plug on the pump and eventually suck rubber trash into pump killing it. Given todays crap gas I would follow all the above advice and I would change the isolator every so often to prevent deterioration from becoming a problem. Just my thoughts
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Hope you don't mind that I'm borrowing the thread, but I can relate right now.
My fuel pump won't run. It doesen't prime on ignition and bike won't start. Is there a quick way to try and hot wire the pump so I can know for sure if I need a replacement? 1996 k11lt
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Please give us a hint, Rami. Have you inspected the fuel pump fuse in the fuse box or checked the fit and condition of the various critical electrical connectors mentioned in this and other threads yet?
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Please give us a hint, Rami. Have you inspected the fuel pump fuse in the fuse box or checked the fit and condition of the various critical electrical connectors mentioned in this and other threads yet?
Yes, sorry. This has been done. First thing I checked was of course the fuse. After searching the forum I checked connectors, my bike is in fairly good condition and connectors are fresh.
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Maybe members more experienced in electrical troubleshooting shortcuts—like Robert or Inge—will chime in here. I'd be plodding along using a wiring diagram to check current input at the fuel pump fuse, output from the fuel pump relay, proper switch function and so on.
Sometimes, Rami, you just have to pay your dues by poring over the millions of words in the "Fuel System" posts in the Child Board section of the workshop using the search box and then take a long nap.
It's also more effective to start a separate post with your personal bike's problem to make it easier for respondents to get to the point for you.
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Lastly, but not leastly, following this diagnostic schematic will help. Follow red lines if the answer is "no"; green lines if the answer is "yes". Your bike model differs but the principles are similar.
http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm
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Hope you don't mind that I'm borrowing the thread, but I can relate right now.
My fuel pump won't run. It doesen't prime on ignition and bike won't start. Is there a quick way to try and hot wire the pump so I can know for sure if I need a replacement? 1996 k11lt
I've no idea how different your bike is to mine, but did you read the whole of the thread? I showed how I checked to see if I had a voltage at the pump, then I measured it's resistance. Would have been easy to hot wire to check the pump worked if I had not found that the current was already reaching the pump.
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With the '96 1100LT, the pump should prime for about 3 seconds when the key switch is turned on.
I had troubles with my '95 and it ended up being the motronic multi-pin plug. The contacts got dirty and wouldn't carry enough current to operate the fuel pump relay.
Pull your plug, clean it with some De-oxit(electrical contact cleaner) or similar that you might have available and re-seat it and see what happens.
Cycle your kill switch as well. They get finicky with age too.....
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And check the sidestand switch circuit.
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Thanks for the input, I pulled the pump from the tank last night. Tried to feed it with 12v and it didn't make a sound. The gauze bag was not sealed and the bottom of the pump looked kind of nasty. So my guess is that i siezed?
And check the sidestand switch circuit.
I did not know about this switch. One question though, will the side stand switch only kill the fuel pump? Because my bike will run on starter gas.
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Unless someone has by-passed it, the side stand switch should also stop the ignition circuits as well, same as the handle bar kill switch.
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Unless someone has by-passed it, the side stand switch should also stop the ignition circuits as well, same as the handle bar kill switch.
Great, so I can rule out any of those and continue with my hunt for a replacement pump.
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Ramnaan try reversing the polarity of the wires a couple of times it will sometimes dislodge the crud that is jamming it. Short bursts alternating back and forth.
Regards Martin