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dcbeemer
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I am newbie to the wonderful world of airheads, but am truly loving it! I have a gorgeous blue 1974 R75/6 with 38k miles (I will post pictures soon!) I bought the bike about 3 weeks ago it runs perfectly save one big issue... it isn't charging the battery. It died on me at a stop light today resulting in a tow (all lights began to fade during drive), which was less than great. The generator light comes on at start, goes off when I get it going (indicating that it should be charging) and usually stays off for my 15-20 minute commute through Washington, DC.

I know the battery is good because it died once before and I bought a charger and it charged all the way up and the held the charge, starting for me for 5 days of commutes. The battery is a Harley Davidson 12V 28ah battery.

My question for you amazing experts: What might be causing my problem? Is it a missing point or is my generator dead? How can I diagnose the issue? I will be charging the bike an hour or two at night on to keep it starting strong, but I really want to get this thing charging itself so it can be a reliable everyday rider.

Thanks so much for all your help and if I need to provide any other information, please let me know and I will. Thanks!

Dan

schrader7032
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Well, the first thing you

Well, the first thing you answered...the charge light appears to be working correctly.

My first check would be to put a known good voltmeter across the battery terminals, start the bike, rev to around 3K RPM, and see what the voltmeter reads. It should be 13.5v or greater.

My next thought is that you might not be riding the bike long enough each day to replenish what is lost during starting, especially if you have a lot of stop-n-go riding. A battery tender should help with that.

Try the voltmeter test and let us know what you find.

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dcbeemer
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Thanks

Thanks for the great response. I have ordered a voltmeter and my buddy in medschool said he'd test/calibrate it for me in the lab.

In the meantime, I've been taking the "scenic" route to work, which adds about 5-10 minutes, the white house and the national mall to my commute, and hopefully 5-10 minutes more of charging.

I'll give you guys an update as soon as I have one. Thanks again!

dcbeemer
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Ok, figured everything out

Ok, figured everything out with charging. Was getting good voltage, but just at higher RPM than I was keeping the bike. Bike likes to be around 2500RPM to charge, I was keeping her around 2000. So just need one gear lower in most situations and the bike charges like a champ.

A new problem has arisen. I went for an hour ride the other day, never above 60mph or 5000RPM. I came home and about 15 minutes later went out to run an errand and the bike wouldnt start. Lights were all on and strong. When i push the starter button, it will give me one loud click and then nothing. I took off the front cover and used an allen wrench to rotate the cam once and she fired right up. This morning, I came out to the bike and was back to the same one click, no start. Strangely, I turned the key to the first position (first click after insert where lights come on) and she started up from there. Is this merely a situation where I probably have some corrosion on the points and need to light sand it off? Or is it something else?

Thanks so much!

schrader7032
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Check your battery voltage

Check your battery voltage again, resting voltage and the voltage levels as you hit the start button. Could be your battery is not as fully charged aas you think.

I would also check the starter relay under the tank on the left side of the backbone. If the relay terminals are corroded, you could be not getting full voltage to the relay. By pulling the relay in and replugging a few times, you can get rid of some of the corrosion. Use a small wire brush on the terminals once removed.

The contacts inside the relay could be corroded and they don't always latch. Might be time to buy a new one and keep this old one as a spare.

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'78 R100/7 '69 R69S '52 R25/2

dcbeemer
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Will do. Thanks for the fast

Will do. Thanks for the fast response! Any idea why it might be willing to start from 1st position?

schrader7032
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Isn't the first position just

Isn't the first position just supposed to be parking lights, etc.? If it starts in that position, maybe that indicates that something's wrong with the ignition switch. That could be where all the trouble is.

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dcbeemer
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You are right about the first

You are right about the first position just being parking lights. That said, I am getting clicks with both parking lights and headlights, just more so with the parking lights. Having read your comments and done some research, I am starting to think it must be the starter relay having corrosion. I was able to get the bike started once tonight and rode it for an hour (on a last ditch try after I walked it behind my house to check the battery), it ran great and fully charged the battery.

So I guess my next move will be to follow the steps in my Clymer's to remove tank and clean the connections for the relay. Any tips?

schrader7032
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The starter relay is a 1in x

The starter relay is a 1in x 1in black cube on the left side...don't really have any pictures of the location. It may take a bit to pull up, but once out, you can see the male terminals which can be cleaned. RatShack sells some contact cleaner which I've used before. Others mention a dielectric fluid/grease which helps prevent future corrosion.

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dcbeemer
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Ok, removed tank, removed

Ok, removed tank, removed connectors one by one and using very fine sandpaper, sanded the connections on the starter relay (only 2 of them looked to have a good amount of corrosion). Put it all back together and same issue: Few clicks on first try at parking lights position followed by single clicks and then single clicks with full headlight on. (Lights are very bright on guage and front lamp) I removed the front plate to see and the cam shaft is turning a single click when I push down the starter switch. No start.

I am now at a loss. Ideas?

schrader7032
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Where does the click sound

Where does the click sound come from? It's got to be either the starter relay or the starter solenoid at the starter. At this stage, you would need to follow the voltage from the battery to the relay then on to the starter and find out where the voltage is not getting through.

I would say you should read these articles:

http://bmwmotorcycletech.info/startingprobs.htm

http://bmwmotorcycletech.info/boschvaleostarter.htm

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'78 R100/7 '69 R69S '52 R25/2

dcbeemer
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Ok, so in the last 20 minutes

Ok, so in the last 20 minutes I was able to get the bike started from the parking light position but it basically took me hitting the ignition button 15 times to get it going and it wouldnt work every time I did that (ie I pushed/held it a number of times until it started, let it run for a few minutes, turned it off, tried again, it wouldnt work the first time but would work 10 minutes later). The lights are all still bright and it idles/revs very well.

This is a bike that started on the first push of the button for the first 30 days I owned it. Thoughts?

schrader7032
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Loose connection

Loose connection somewhere...I'd open up the headlight and look at the ignition switch. It might need to be replaced. I wonder if the PO did something to it. It shouldn't start from the 1st or Park position.

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dcbeemer
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Its a new-ish Bosch H4

Its a new-ish Bosch H4 halogen, opened it up last night, all connections looked clean, ignition switch looks almost new (PO upgraded to the halogen). I replaced the points under the front cover, just to see if that would help. Same situation: bright lights, push the start button and get a click from cam shaft, which turns a click or two, but no start)

Will take another crack at the starter relay tonight/tomorrow, actually remove it to give it a good dusting off (although it looked pretty clean compared to the spare old one that the PO gave me).

Waiting on voltmeter in the mail, but am really getting depressed that I cant figure this thing out, other than the charging issue that I thought I had worked out with higher RPMs, this bike started like a dream for the first 30 days I owned her and I would love to avoid the cost of taking it to Bob's BMW.

JD
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Having read through this

Having read through this entire post, it almost sounds like the battery isn't holding a charge and/or can't handle a load. This is reaffirmed, at least in my mind, by the fact you said the battery died. If it went to 0, it's shot.

Even if a battery is new, you can't assume that it's good. You can do a simple load test to at least get a preliminary result, or take it to an auto parts place and have them load test it.

If you want to test it yourself, make sure the battery is fully charged. Attach a voltmeter to the battery terminals and take a reading. Turn on the low beam on your headlamp and take another reading. Wait at least two minutes (I usually wait about 5 to get rid of the surface charge) and take another reading. Your voltage should read around 12 volts. I'm not sure which voltage will cause the ignition to drop out, but a starter puts a heck of a load on a battery. It's simple and time efficient to test the battery, and if it's not the cause of your problem, at least you'll have peace of mind knowing you have a good battery.

Darryl.Richman
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The way to tackle any

The way to tackle any electric gremlin is to divide and conquer.

Definitely do the battery load test above. A bad battery will waste a lot of your time.

When you press the starter button, you should be able to hear and feel the starter relay click. If it doesn't click every time, then the relay or the wiring to it is suspect.

If it clicks every time, then the red wire from it to the starter solenoid, the power lead from the battery, the solenoid itself, or the starter are suspect.

If the solenoid clicks every time you hit the starter button, then it's either the big power wire from the battery, it's connection at either end, or the starter itself -- either the motor is stuck (the permanent magnets in some of these can come unglued) or the "bendix" needs cleaning. You can try tapping the starter with a rubber mallet (don't wail on it, just a "love tap") to see if it jars the motor free.

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Bruce Frey
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Another quick way to tell if

Another quick way to tell if the problem is with the starter motor is to turn the headlight on and try to start it (with a charged battery). If the headlight goes out, the problem is usually the starter motor. If the headlight does not go out, the problem is upstream of the starter motor.

Bruce

dcbeemer
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Thank you guys so much. I

Thank you guys so much. I just got the voltmeter, so I will try all of these when I get home today and report back.

dcbeemer
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Ok. Get home, charge battery

Ok. Get home, charge battery on 10 amp charger for 2+ hours. Instrument reads 12.7V when off, 100% for my battery. Turn it on, 12.4V. Let it sit for a few minutes with lights on, 12.3V. Hit starter button, I'm getting good sounds, sounds like engine is turning... but it won't start. It will turn over for as long as I hold the start button but wont start. Tried a few time but stopped, didnt want to do too long for fear of flooding the engine. After trying a number of times, with same results, checked V with keys out, 12V.

Thoughts?

dcbeemer
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When you press the starter

When you press the starter button, you should be able to hear and feel the starter relay click. If it doesn't click every time, then the relay or the wiring to it is suspect. Yes, clicks everytime

If it clicks every time, then the red wire from it to the starter solenoid, the power lead from the battery, the solenoid itself, or the starter are suspect. How should I go about checking these?

Also, headlight does not go out when I push start button

schrader7032
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So, if the starter turns

So, if the starter turns over, then we have different problems. It's down to spark, fuel, compression, timing. Probably not compression. What about fuel? Properly choked? Spark? Pull a plug and put it back in the plug holder and ground the plug threads to the engine. Probably should do both plugs so as to ensure that it doesn't start...also get the plug somewhat away from the open plug hole. Retry the starter...nice fat blue spark or weak yellow spark. Timing? The spark needs to jump when the S-mark is in the window. You could hook up an induction timing light to your plug leads/grounded plugs and see what the timing is.

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dcbeemer
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Removed plugs. Heads were

Removed plugs. Heads were totally dark grey/, no gunk or buildup. Key in, press start button, engine tries to turn over, so some air comes out of spark holes...NO SPARK on either plug. Switched one out for a clean one just to see if that was issue, NO SPARK.

dcbeemer
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Maybe install old points to

Maybe install old points to see if that helps? If its no spark, is it down to point, condenser and coil?

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Do the points open or close

Do the points open or close at all? If not, you would get no spark. I'd be checking the static timing...

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dcbeemer
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I will install the old points

I will install the old points unit tomorrow morning. Why would my static timing have changed? This bike was running really well (when the battery was charging)

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Sometimes that thought can

Sometimes that thought can lead in wrong directions. The timing probably hasn't changed but it would be best and easy to eliminate. But it's possible...the rubbing block could have worn considerably with no grease, the screws holding the points plate might not have been tight resulting in a change, the large bolt holding the advance unit in place could also have been loose leading to a change. I believe the /6 is like my /2 in that the advance unit is keyed onto the end of the camshaft. It's important to find that key each time and to hold the advance unit up against the side of the key while the bolt is tightened. That way, you get consistent timing if the advance unit is taken off for some reason.

I think the point is to begin eliminating the easiest things first and usually the things you last worked on. But if this happened all of a sudden, then you have to wonder about everything until you rule it out.

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dcbeemer
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Finally gave in and took it

Finally gave in and took it to Bob's BMW in Maryland. They just called me and told me that the starter motor was drawing too much power and needed a rebuild (at a cost of $450). Can this solve my problem completely?

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Starter drawing too much

Starter drawing too much power creating a non-charging issue? Sounds like they're fishing to me. Is the issue still non-charging or is it non-starting or no spark?

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dcbeemer
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Issue is non-starting due to

Issue is non-starting due to no spark. And if starter was drawing too much power, couldnt that be the reason the battery was dying on me?

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Seems to me that if it was

Seems to me that if it was drawing enough power to provide no spark, it would also not even turn the engine over. The starter's job is to turn the engine over so that the points open and close enough times to saturate the coils and break the saturation to create the spark.

To test their theory, jump start the bike with a car battery. Don't turn the car engine on, just make the battery connection. Then try and start the bike. If you still get no spark, then I'd say that the starter motor theory doesn't hold water.

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BrianR100RS
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firing issues

danshott wrote:

Its a new-ish Bosch H4 halogen, opened it up last night, all connections looked clean, ignition switch looks almost new (PO upgraded to the halogen). I replaced the points under the front cover, just to see if that would help. Same situation: bright lights, push the start button and get a click from cam shaft, which turns a click or two, but no start)

Will take another crack at the starter relay tonight/tomorrow, actually remove it to give it a good dusting off (although it looked pretty clean compared to the spare old one that the PO gave me).

Waiting on voltmeter in the mail, but am really getting depressed that I cant figure this thing out, other than the charging issue that I thought I had worked out with higher RPMs, this bike started like a dream for the first 30 days I owned her and I would love to avoid the cost of taking it to Bob's BMW.

Did you set the points to the right gap and check the static timing with a 12volt test light?
If you were getting spark and it started before you changed the points sounds to me that the points are not set.

sounds that it was firing before the points change, (just a charging, or connection problem) is what you were having.
Did you check the contacts on the push button start, or the connections on the solenoid at the starter?

A short, or loose connection will cause a voltage drop while also raising the load amount, I don't see how a bad starter will keep it from firing. (I am no BMW expert but i have had my fun with points, timing and electrical issues on older bikes. this is just my 2cents)

It is not a fuel injected engine, or electronic ignition, so if everything was in time and set right you should be able to push start it in gear with out a battery and it would start. So I don't see how a starter would keep it from firing, "As I Said I don't know much on BMW's" but when building my Honda I started the engine without the rectifier, regulator, or battery, just kick started it.

If the winding in the starter is shorted to ground or weak it would increase the load, does it have safety switches on it where it won't start if the clutch isn't pulled in, or in natural? maybe a short on one of them, keeping it from firing, or the kill switch?

When you pressed the start button, you said you heard the relay click, do you know if the solenoid, was clicking also?

These are all just things that I would check and go over as a process of elimination.

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BrianR100RS
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one more thing

One other thought on the firing issue, the wire that comes off your points isn't grounding out is it?

I was browsing ebay, came across a starter that has 1 day left on the auction and is at $15 right now.
bmw starter

Just thought I would pass it along man, cheaper than $450. I am not in anyway affiliated with this auction, and if posting ebay items here is prohibited I Apologize, not trying to go against the rules, just trying to help out.

Brian

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Dave Reina
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Battery charge and turning engine over

Hi Dan,

Sorry to hear your are having these problems with the bike. I wonder if the starter was drawing too much current and then the voltage to the coil was too diminished and not enough to give a good spark? Does Bob's offer a rebuilding service for your starter rather than a new one? It should be half the price of a new one.

Two other thoughts as I read your notes to the forum. One is that I think a 10 amp charger may be too strong for a motorcycle battery and can overheat the battery and warp the case. Generally bike chargers are 1 1/2 to 2 amp units. You said you had a HD battery and thats fairly large which may be able to take a bigger charger, but you might check with the battery supplier to verify.

Second is that you say you turned the cam. Best to turn the engine from the crank allen screw rather than the cam.

And last, it is important to disconnect a battery lead when taking off the front cover to avoid shorting something on the charging circuit.

I hope you are back riding soon.

Dave Reina

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schrader7032
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Cam or Crank?

Dave Reina wrote:

Second is that you say you turned the cam. Best to turn the engine from the crank allen screw rather than the cam.

I noticed that he said he turned the cam with an allen wrench...there's no allen bolt on the camshaft tip, so likely he just meant the crankshaft at the front of the alternator. I used to do that to turn the engine, but it can be difficult turning against the engine's compression...a possibility of stipping out the allen socket. Suggest removing the spark plugs in this instance, or what I've been doing for years, put the bike in 4th or 5th gear and turn the rear wheel.

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'78 R100/7 '69 R69S '52 R25/2

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Argh! I sat here reading all

Argh! I sat here reading all 33 posts - so what happened? What was the issue? I am dealing with something similar, and it would have been helpful (and a nice way to pay back those who spent time helping) to have posted a follow up! Was it the starter? Wiring? Solinoid? Switch? This is like reading a nail biter mystery novel only to turn to the last page and find it missing.

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