MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Lawrence on October 27, 2011, 11:00:59 PM
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After work tonight I tried to finish the last "little" tasks subsequent to lubing the splines on my K100RS. I discovered in now refuses to start. When the ignition is on, the instruments are lighted but the starter simply makes an odd sound, and very faint at that. I first thought the battery was kaput after sitting about 10 days with the help of the trickle charger. Then I noticed that, even with the ignition off, the headlight (only) was on. What the *%!# have I screwed up now? Have I mixed up the connections to the battery posts? Fried an extremely expensive electrical wigget? The cabling to the battery seemed very simple and straightforward and I didn't bother to label them. Mistako!
The bike has one smallish cable that seems to exit the bottom of the airbox, and a a large gauge (starter?) cable that is in a sheath with another smaller cable. Both of these I attached to the positive post. The only cable on the negative post is the amazingly small ground cable. Are those the proper wiring connections?
On the other hand and if I'm lucky, maybe its just a dying battery that has caused this mystery. I disconnected the ground and hooked the battery to the trickle charger; the red light illuminated straight away telling me the battery is weak. But could this explain the headlight remaining lit?
Some ideas of where to go from here, please.
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freakadelic there lawrence
pictures are our friends here at motobrick.com...
a photo of your battery and how you gotts it wired would be helpful...
j o
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Okay, I'll try to post a pix of each battery post. Note the cables attached with the colored (red, black) flags are for the pigtail that I use for the trickle charger. That's the only cable I can be certain is correctly connected.
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And then the positive post ....
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im at work... using my phone... i can not see the battery...
im thinking 1 unobstructed overhead shot of the battery is what i need for the phone...
sorry...
j o
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And what is the damn battery voltage? If you measure it with a voltmeter it can help you determine many things about the problem...but ya gotta have some data.
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lawrence...
are sure you didnt turn the key to far ccw to the parking light position...
j o
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The damn battery measures 12.6v at the terminals. My camera's batteries decided to die, so I can't provide an unobstructed pix from above the battery just now. As for the key position in the switch, I turned it as far as possible counter clockwise and the headlight remained illuminated. It only went out when I disconnected the ground wire.
The bike started easily before I disassembled the rear half to lube those pesky splines. When I have a mechanical issue, I have found it productive to check the last thing I did to the bike -- thus, the question about the connections to the battery. In essence, my question is this: On a 1985 K100RS that is bone-stock other than a pigtail for a battery charger, should there be any cable other than the ground strap connected to the negative post of the battery? The wiring diagram in the owner's manual indicates no, but I've grown suspicious of BMW docs of late. There are some inconsistencies.... hence my question to this forum. Thank you.
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No other cables connect to the battery negative terminal except the ground strap/wire that runs to a [
lock-tited]socket-head cap screw on the left rear side of the [transmission] housing in the region above the footpeg. Don't try to remove that cap screw--they intended for it to be permanent.
Your damn battery is not fully charged-- the voltage should be 12.8 or higher. The static surface charge on the plates can give a reading of 12.6 making you think it might be okay, but when it is put under a load (headlights, starter, fuel injection, etc.) the truth will be revealed. Connect the voltmeter and watch what happens to the voltage when you turn on the ignition switch and headlights, then what happens when you pop the starter button. If it gets pulled down below about 10.5 then it is suspect and on it's last legs.
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lawrence...
are sure you didnt turn the key to far ccw to the parking light position...
j o
JO: The two valve Ks have a different ignition switch than the 4 valvers.
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No other cables connect to the battery negative terminal except the ground strap/wire that runs to a lock-tited socket-head cap screw on the left rear side of the motor in the region above the footpeg. Don't try to remove that cap screw--they intended for it to be permanent.
If yours was Loctited then it wasn't done at the factory. I've pulled apart/serviced tons of Ks and never found Loctite there on a single one. It's not meant to be "permanent."
It bolts to the left side of the transmission, not the engine block.
Your damn battery is not fully charged-- the voltage should be 12.8 or higher. The static surface charge on the plates can give a reading of 12.6 making you think it might be okay, but when it is put under a load (headlights, starter, fuel injection, etc.) the truth will be revealed. Connect the voltmeter and watch what happens to the voltage when you turn on the ignition switch and headlights, then what happens when you pop the starter button. If it gets pulled down below about 10.5 then it is suspect and on it's last legs.
12.6V is more than adequate to start a bike. As I mentioned earlier, it's the cranking amps it can put out that matter more so load-testing is the only reliable way to test battery health.
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On a 1985 K100RS that is bone-stock other than a pigtail for a battery charger, should there be any cable other than the ground strap connected to the negative post of the battery?
The only thing on the negative post is the ground cable to the left side of the transmission. While you have the battery cables off it's a good idea to hit the cable terminals with some coarse steel wool or a metal brush to clean them off to improve their conductivity.
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As for the key position in the switch, I turned it as far as possible counter clockwise and the headlight remained illuminated. It only went out when I disconnected the ground wire.
This is very suspicious behavior. Does you bike have headlight relays installed? (They would not have been installed by the factory but it's a common owner mod.)
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I've never removed the fuel tank and traced the wiring to the front of the bike. However, I have to believe that if there was a headlight relay, there would have been more cables to attach to the battery posts. (I have order a headlight relay from Eastern Beaver just this week). After work today I will remove the battery and take it to get a load test. I don't know if I want it to pass or not ::) If it passes, that means a continuing mystery in the electrickery; if it fails, I'll have to pony up for a new battery :-\
Sure would like to put some miles on her before it becomes much colder....
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A lot of people (smart guys like me for example) power headlight relays in the relay box at the power input terminal for the starter relay.
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and smart people con others into loaning out their catz azzure white 4100k 55/60 cause it blows away their chinese junk thats hooked to their starter relay...
j o
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and smart people con others into loaning out their catz azzure white 4100k 55/60 cause it blows away their chinese junk thats hooked to their starter relay...
j o
Dude, whenever the Big Brain lets you come back down here we'll go out at night and my $4 90/100 Chinese Xenon will make your Catz ch1t look like kitty litter.
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subsequent to lubing the splines on my K100RS.
Did you happen to remove the ground strap on the transmission when you did the spline lube?
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Well yes, of course I disconnected the ground wire. I don't know how to lube the splines without removing the battery and....
Upon return home today, I measured the volts across the battery posts again. 12.9. When I did the recent spline lube, I cleaned all the electrical connections I came across - contact cleaner and wire brush stuff. I'm convinced the battery is strong enough to start the bike. I don't believe this is an insufficient power issue. There's something else going on here. The moment I connect the - lead to ground, the lights come on (instruments, headlight) yet the bike's starter will not operate. I suspect the ignition switch. How can I test it?
I'm hoping there's a simple (read: stupid) mistake I made while learning to lube the splines and not some exotic and expensive component failure at the bottom of this problem.
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Edit 2: BrickFlyer has a great link with excellent info in the following post. i have swiped part of Bert's troubleshooting image and added it here to my message.
Edit 1:The load-shedding relay contacts have to be closed for power to reach the headlight. That could happen for two reasons: [1] the relay contacts are welded together, or [2] the ignition switch contacts are shorted, thereby sending power to the relay control coil which is grounded thru the starter motor and pulls the relay contacts closed.
The most likely candidate is [2] due to a dirty or broken ignition switch, but to determine which it is
i would remove the negative ground wire at the battery, and then remove the fuel tank. Trace the wiring harness from the ignition switch down to the right side of the frame to where it enters the electrical box--there will be a four pin connector in that harness. Disconnect the 4-pin inline connector and reconnect the ground wire to the battery. If the headlight comes on then the relay contacts are welded together. If not then the ignition switch is the culprit.
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<<I suspect the ignition switch. How can I test it? >>
Here's a link that I found helpful when troubleshooting the electrical system on my 85 K100RS.
http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm (http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm)
Inspecting and cleaning the ignition switch is not that tough. I was glad I did it on my bike since I found that several wires were down to a few strands and most of the insulation had rotted.
To remove the switch you just remove the fasteners holding the rubber housing that the ignition switch sits in, then take off the bezel ring around the ignition switch which will expose I think three little slots around the circumference of the switch. These slots let you access some little plastic tabs that lock the switch into the hole. Once the tabs are pried back you push the switch out the bottom if I recall correctly. Don't overdo it as you could break the tabs entirely if you are too aggressive. The article below will give you a feel for what I am talking about.
Then you can inspect the wires and use an ohmmeter to check the contacts. You can also disassemble and clean the ignition switch even though BMW says there are no user serviceable parts inside. That task is documented here:
http://ibmwr.org/ktech/ign-switch-disassemble.shtml (http://ibmwr.org/ktech/ign-switch-disassemble.shtml)
I cleaned all the contacts with CRC, lubed it with dielectric grease and it popped back together.
Your problem and symptoms are different than the issue I was chasing, but if your 26 yr old wiring is as bad as mine was it may prevent a future issue.
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+1 BrickFlyer
Edit: wrong thread, but sound sound advice from BrickFlyer
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Just read this over. You may be hearing the fuel pump running, rather than a starter. Kind of a whir/buzz.
What you should do is take jumper cables from the positive terminal and touch them to the starter terminal. You may have a dirty or worn starter. If it doesn't crank the starter with a know good battery hooked to the terminal (Behind coils), that is the answer.
You can also try putting it into 5th, and backing the bike up to turn the starter to a different place on the commutator. Or try bump starting it.
The starter stuff can cause other weird things. The load shed relay is grounded through the starter motor. If the commutator or brushes are worn or dirty, it can cause all sorts of problems.
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(http://img.photobucket.com/albums/v377/Nightwing749/6icZ3.png)
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Quote from: johnny on October 29, 2011, 05:36:04 PM
(http://img.photobucket.com/albums/v377/Nightwing749/6icZ3.png)
ROFL ... perfect.
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Curious minds want to know why you felt the need to quote the image?
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That diary story is a hoot -- and comes so close to reality its scary. Plus, there's the bonus of a pix of a lovely lady. Thanks!
I've invested another entire weekend in the RS. However, I'm going to sleep happy this time. In the course of fitting some of the Euromotoelectric high quality electric cables to the bike I discovered my wiring error. It's such a stupid mistake its not only an embarrassment, but it has me thinking I should restrict my personally-done maintenance to adding air to tires. I am fully capable of doing more harm than good in any given situation. :-\
On the bright side, I've learned a lot. Thanks for the many helpful hints and suggestions. This is a valuable resource for a new flying brick owner. Crawling up the steep learning curve has also given me a warm and fuzzy feeling to balance the frustration I've brought on myself because I'm now pretty sure that the 25 K miles on my 1985 K100RS is pretty close to reality. The splines are virtually new; when I stripped the ignition switch for cleaning and inspection I found very little wear there too. The only weak point on the entire motorcycle seems to be the rust and corrosion on the frame and alloy surfaces.
Looking to the near future, I would like to fit heated grips and a headlight relay. Then ride her til I can't throw a leg over her any more. Do I dare tempt fate again...?
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Curious minds want to know why you felt the need to quote the image?
Same reason I quoted this ... so the clueless masses will know what I am responding too.
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the clueless masses
Didn't realise that any of our august group fell into that category ::)
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the clueless masses
Didn't realise that any of our august group fell into that category ::)
Nor did I realize it would be necessary to explain why one quotes a post to this intrepid group of anti-pirates. Apparently the answer is yes on both counts.
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time. In the course of fitting some of the Euromotoelectric high quality electric cables to the bike I discovered my wiring error.
Share the discovery please... it helps to know what not to do. Everyone that put time in trying to help deserves at least that much.
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Okay, okay I'll come clean. I was trying hard to avoid being the goof-up poster boy but if you insist (and promise to keep this under your hat). There are two spots on the left side of the engine where an electrical wire can be connected. I managed to put the ground wire on the wrong one.
Okay, now I have to go under deep cover....
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the clueless masses
Didn't realise that any of our august group fell into that category ::)
Nor did I realize it would be necessary to explain why one quotes a post to this intrepid group of anti-pirates. Apparently the answer is yes on both counts.
Well, not to drag this out but there are times here when people quote a post with one or seven images in it which seems overkill to me; and tends to give my older machine/browser a hard time. I do understand quoting, I just don't understand over-quoting. Whatever, I'll not say any more on the topic lest it be misinterpreted.
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the new forum software that we are upgrading to has a feature where only text will be quoted... not images... yeeeeehaaaaaaaaa...
and for you photo conscience attachers... 1024px × 768px should be max size... this system will not limit the height width... the new system will...
so until we upgrade please keep images to 1024 x 768 or less...
j o
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Halloween is behind us. Please retire those pix :(
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Halloween is behind us. Please retire those pix :(
Thank you.
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You guys crack me up! ;D
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This is too much like 2nd grade.
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i skipped 2nd grade...
j o
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i skipped 2nd grade...
j o
No, it skipped you. 8)
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Nancy is scary enough w/o the makeup.