The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: noah on August 30, 2008, 05:11:04 PM
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Hi everyone,
I once knew the solution to this problem, but its been a while so my brain is rusty. The bike starts fine with a jump, the battery is solid (I've had it tested several times) and it even idles well if the choke is on. But, as soon as it starts idling low enough for the red "laurelauf" or whatever that light says, to come on, the bike dies. It won't even start without a jump; if I try it almost immediately starts making that terrible clicking sound.
I have a feeling this has something to do with the alternator or rectifier but I forgot what exactly the procedures are for testing these things. It has something to do with a voltometer and testing one or other of those parts somehow when the bike is running.
Can anybody refresh my memory and/or offer other suggestions.
Thanks!
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Sounds like you may have several issues, a compound problem as it were. What year R65 are we dealing with here? Get a hold of a volt / ohm meter. Were going to go after the starting issue first. I want to see what the battery voltage is at rest and what the voltage at the battery terminals is when you push the start button. Others will chime in shortly to guide you on this and have you start checking coils, carbs and so on. Grill is hot, gotta run.
rich
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shoot. I forget to test when I press the start button. Here's this for now, then I'll run down and do that:
OFF: 12.1 v
ON: @ 1.5rpms -- between 8.5-8.7 v. Voltage dropped as rpms increased and visa versa.
When I turned it off after testing, the volts slowly climbed back up to 12.
Back in a sec.
Oh, and its a 79 R65 with 65,000 miles. It sat for a couple months because I couldn't figure out this problem but now it runs fine when it runs.
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Ok, here's the news:
OFF: the battery was about 11.8 volts.
On: with headlight on about 9 and change volts.
Starter depressed: 7.4 volts and dropping
When I pressed the starter, the bike made a very slow, gutteral, clicking/chugging sound and the volts dropped to 7.4. When I held down the starter for a couple of seconds the volts slowly dropped till I let go at 6.8 volts. When I tried to repeat the test, nothing happened when I pressed the starter. No sound, no drop in voltage, nothing. This is how it usually goes until I jump the battery again.
Help . . .
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Did you charge the battery before your tests? If so, it is definitely dead. If not, charge it up and repeat them. If it shows good with a full charge, then you need to test the bike's charging system to see why the battery runs down.
I killed my Triumph's battery the other day by leaving the key on. I hope I didn't cook a coil as well. :(
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Did you charge the battery before your tests? If so, it is definitely dead. If not, charge it up and repeat them. If it shows good with a full charge, then you need to test the bike's charging system to see why the battery runs down.
I did charge the battery and ran the bike before the tests. I've also taken it into to auto shops several times and had them trickle-charge it overnight and then test it on their machines. Every time they tell me the battery is fine, so I'm inclined to think that the battery is not the problem. Also, the bike will run fun when I ride it until I come to a complete stop or try to move out of first, when it dies if the rpms get too low. This also makes me think its the charging system and not the battery.
How exactly to I go about testing the charging system to isolate the problem?
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To check the charging system the method I know of is to have the bike running [you'll need to jump it again] and check the voltage once more at the battery terminals. Above idle at oh say 2000rpm you should see 13 volts or above. If its below 13v at running speed the regulator or generator may be faulty but first clean up all your electrical connections at the regulator. There is a simple way to jump the regulator with a short piece of wire but I can't recall which pins get jumped.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi101.photobucket.com%2Falbums%2Fm70%2Fmrridden%2FR65LSa.jpg&hash=9ebb9f784a404b3c58c4daffaaa8d8e2090b689a)
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If your "fully charged" batter reads only 11.8 volts then it is most likely bad or was not charged. A fully charged battery, at rest, should read over 12.5 volts. Also, as your voltage drops when the RPMs go up your charging system is not working and could be the root cause of your ailing battery. Batteries do not like sitting around in a less than charged state...
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but first clean up all your electrical connections at the regulator.
How exactly do I do this? Assuming it is the charging system as Justin indicates, now what? What's the next move, in baby steps please.
Thanks
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Here's a set of articles on the electrical system. He's long on explaining how it works, but in fact, these bikes don't have a particularly simple charging system.
http://bmwmotorcycletech.info/boxerelectrics.htm
http://bmwmotorcycletech.info/electricalhints.htm
http://bmwmotorcycletech.info/trbleshootALT.htm
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Ed, do you really mean "do have..." ?
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Thanks for the crash course in electrical engineering, Ed. It was very informative.
I still need to know what the next step is to isolate my problem. The volts do indeed drop as the engine accelerates. This probably means there is a problem with the charging system. Good, got that covered. What I'm still not clear about is how to move forward in diagnosing specifically what part of the system is giving me static and how to fix it.
Does "clean up all your electrical connections at the regulator" mean remove them from the terminal and hit them with a brush? :-/
Should I test the resistance on these wires or is the problem something internal to the regulator? In which case then what? Replace? Jump using the unknown method that Mr. Riden suggested?
Help . . .
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OK I found it. Remove the Voltage Regulator from its socket. You should see 3 female connection points. If yer really lucky they will even have identifying letters [or look on the regulator itself for corresponding id letters] They will be marked f+, f- and Df. We want the f+ and Df connectors that are directly opposite each other. The wires will be Blue and Blue with a black tracer or even all black. We DO NOT want to use the brown wire. Make up a handy little jumper wire with a male spade connector on each end [you now have a new tool for your on board tool roll] insert the jumper to connect the f+ and DF wires to each other [blue & blue black] Get 'er started however ya need to and check the voltage at the battery terminals. Got 13-15 volts? Go to your local auto parts store and get a Borg-Warner R-588 or Neihoff WA 709.
A good parts counter person can cross reference against either the Borg-Warner R-588 or the Neihoff WA 709 numbers to find one that werks. I suggest these because they are half or less than the BMW part.
If however you jumper out the regulator and still do not see sufficient charging We're going to take off the front engine cover[ disconnect the battery first!] and begin by checking all the connections [clean / tight / connected] at the diode board. You may also have bad brushes on the alternator [not hard to change but fiddly] or the most expensive, open alternator windings. Lets go for the regulator first 'cuz it's cheap and easy.
rich
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Noah
Do Not Remove the engine front cover without disconnecting the negative battery cable.
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Don't forget to check the alternator. I had very similar problem with my R100M. I checked everything I could per the manuals, but could not isolate problem. Finally took it to dealer and found out the alternator rotor was bad. Rebuilt one fixed the problem.
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Here's the news: using the aforementioned method to jump the regulator by connecting the blue and black wires yielded the following results:
At ~ 1100rpm: 8.4v
At ~ 2000rpm: 12.0v
In general, between those two posts the volts went up with the rpms and visa versa. At NO time did the volts approach anywhere between 13 and 15. Then again, I didn't run it at anything higher than about 2100 rpms because I didn't want the engine to overheat.
I discovered a separate issue while running these tests. The left piston is running much hotter than the right one. I checked the plugs and the left one was jet black, while the right one looked fairly normal (white/brownish with some black spots). Is this problem related to the charging system or something totally different? Will a simple carb balance take care of this?
Thanks
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Ed, do you really mean "do have..." ?
I think it's complicated. Sometimes the phrase "simple by choice" seems really cynical to me.
Complicated doesn't mean it's not better than a permanent magnet alternator with a unit rectifyer/regulater, just that it's more complicated.
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Hmmm...
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Now that we have the issue of the intended simplicity/unintended design shortcoming no closer to being settled, can we get back to the issue at hand???!! Not to be pushy, and thanks everyone for the help, but its supposed to rain tomorrow so I'd like to get this fixed before I have to move the bike inside for winter.
The voltage reading at the terminals is waaay low, even with the regulator "jumped" by connecting the blue and black wires. Also, the left side of the engine is running significantly hotter than the left. Is this problem related or something different?
But first, what the hell does it mean when the battery is running low on voltage???? Is this a problem with the alternator rather than the regulator?? Bad brushes, as someone earlier suggested??
Please, throw me a bone here . . .
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I discovered a separate issue while running these tests. The left piston is running much hotter than the right one. I checked the plugs and the left one was jet black, while the right one looked fairly normal (white/brownish with some black spots). Is this problem related to the charging system or something totally different? Will a simple carb balance take care of this?
Thanks
Do a thorough check of the fuel lines, they must not be frayed at any points, check for airleaks. Check the plug cable connection, clean the plugs and change them. Check that the throttle cables have the same play at each side (appr. 1/20 to 1/15 inch when idling). Check that the choke is not hanging on either side. Take the bike for a ride and do at least 10 miles at 5000 rpm, stop and check the color of both plugs. If you still get a black plug on the left side you have a problem with your left carb running on a too rich micture. Begin with checking the airscrew at the bottom of the carb: turn it to full stop and the 3/4 turn back. If you do this with the engine running you will hear the engines rpm change from slow - higher - slower. Stop at the highest rpm. Clean the plugs again, go for a new ride, check the color of the plugs and if the left still is black you will have to dismantle the carb, cleanse and adjust it.
Other causes for malfunction may be the ignition coil(s) or very rarely the connections from the "bean" can, but try the easy measures first.
greetings from a partly sunny north
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I've also heard that side stand parking can cause oil to be trapped in the left cylinder head on bikes with a lot of miles on them. Seems a bit "hokey", but who knows. I usually park on the center stand so can't speak from experience.. :-/
Ed
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Noah, does your charge light stay on when the bike is running, especially at the higher rpms? If not, is it burned out? It should always come on when you turn on the ignition switch before starting the bike. I have read that if that bulb is burned out, the system won't charge. That, too, I find ironic.
Here's another article I found:
http://www.buchanan1.net/charge.shtml
I have never found a simple, step by step electrical trouble shooting chart for these bikes. I want one but am not qualified to make one myself.
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Yes, the "GEN" light should be on when the ignition is turned on, prior to starting the engine. do verify that it does this so that we know the bulb isn't burned out or broken.
As Ed mentioned, if the bulb never lights, you'll never get the proper charging behavior with the regulator and the alternator, particularly at low RPMs.
If the bubl does light brightly with the key just turned on, then we can look elsewhere.
Usually if a plug/cylinder has alot of oil in it, one will get heavy, ash like deposits on the plug, but if it is simply just black, thin deposits it is simply running (much) too rich.
Possibly the other cylinder is running much too lean - usually the leaner running cylinders run the hottest, unless things are so bad that you're literally still pumping unburnt gas into the header pipes...
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This is beginning to sound like hell in a handbasket . . . the charge light works fine. It comes on with the key in and stays lit when the bike is at low rpms and then goes out past around 1800 rpms, as it should.
As far as the cylinder goes, the one that appears to be running richer is definitely the hotter one. I still don't know what that's all about. I prefer to fix the charging system first, and then mess with the carbs and everything else.
Since no one seems to have any more advice regarding the electrics, does anyone know of a shop or mechanic in the Twin Cities that works on old beemers?
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This is beginning to sound like hell in a handbasket
Nah, not even! ;D based on the result of your test I'm gonna tell ya to slap the Voltage Regulator back in. You should have higher voltage readings [duh] next [step by step via internets is a sloooow process ya only completed one so far] is to isolate the trouble to either the Diode board or the Alternator Brushes. for this I'm gonna refer ya to the Haynes Manual Section 10.6 [see Haynes is good fer sumptin'] You either have a fried Diode or bad brushes. Thats it! one or the other [or dirty connections] but not an open rotor. Ya gots some other stuff goin' on there too but stick to the charging problem for now. If you decide to hand it off I'm afraid I'm not familiar with BMW shops in Minnesota [want some walleye with that?] BUT I do know of an excellent Britt Bike place that could and would point ya in the right Direction for a reputable BMW mechanic
http://www.britishbikerepair.com/
rich
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Ok, here's an update. I pulled the diode board off and it looks ok to me. Then again, I don't really know what I'm looking for so that might not mean anything. I've attached a picture. There was some rainbow-ish discoloration on the board at 2 of the contact points, but I don't know if this is extreme or just normal wear and tear. I've attached a picture.
I also pulled off the alternator stator (don't have the tool to pull the other part off) and checked the brushes. They are not shorted than the wear limits in the Clymer manual. They don't look terrible to me, but see above. I've also attached pictures. Could it be that the alternator itself is shot?? It looks a little banged up, but what the hell do I know. Is there a way to tell?
Feedback from everybody please, then, if we ever get this part fixed we can work on the lopsided engine.
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here are the alternator brushes. Sorry for the crappy photo quality (the camera sucks) and the huge picture size (I'm as good with computers as I am with charging systems).
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Apparently you may also have a VCR that is still blinking "12:00", but that's OK, we'll help you get through it ;)
(Couldn't resist the jab at the date/time stamp of pics)
Unfortunately, those pictures are pretty fuzzy _ I have a hard time trying to see any relevant details.
Can you try to get one of the OTHER side of the diode board ? Maybe try moving back just a bit further with the camera and it might be in better focus.
Things can get hot on that diode board, and sometimes a little discoloration is just that and nothing else, but from that side and the fuzziness of the picture it is hard to tell.
The earlier (pre-79) diode boards were more prone to sometimes "unsoldering" themselves due to heat, than the later ones.If it comes down to replacing the diode board,
one can obtain a unit that is considered better than the OEM unit AND for less money (how 'bout that !?!?) from several sources - the manufacturer is called "Thunderchild"
and will set you back about $95 or so. But, we haven't reached that point inthe diagnosis yet.
Do you have a multimeter or Volt-Ohm meter handy ? There are some resistance checks that you can do with the alternator & brushes but you'll have to put them back together somewhat to do this... I am trying to locate the info on how many ohms you should see measuring at different points of the alternator, but the bookshelf is not giving it up easy today.. before you removed the brushes, where the springs pushing them to make good contact with the slip rings, or could you see gaps ? I think that anything less than 8mm or so on the brush length is too short/worn out, though the spring might be able to still keep things close, but not quite touching, at that length.
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No, strangely, the clock on the stove has the correct time and date. It's just a single dial, which makes things much easier. In any case, here is a probably useless picture of the other side of the diode board. I'll also post a useless pick of the inside of the alternator, for whatever that's worth.
I do have a multimeter handy, but you'll have to hold my hand through setting it to read Ohms. Tell the library I greatly appreciate the help, so take his or time with coughing up the info.
The springs were on there pretty tight. I think I accidentally "unsprung" one of them when I was pulling the brush out because I had to pull so hard. I'm hoping the resistance will rebuild over time when I but the brushes back. There didn't seem to be a gap, but I wasn't specifically looking for one either.
The brushes measure 1.5 cm (I'll ask the blinking vcr how many mm that is), which seems plenty good to me. Google says that's 15 mm, which suggests brushes are not the problem.
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in case you still don't have a headache, here's the alternator:
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OK ! I've got a head-ache now ! ;)
The discoloration you see on the diode board might be simply some corrosion, or could be the result of overheating. Things do get pretty hot there anyways, but if a diode has gone bad usually the back metal surface (the 2nd photo) will show a little "bronze" coloring of the normally silvery diode backing. We probably ought not to try to get into testing the individual diodes, but here is some more info for you.
BMW did issue a service bulletin for pre-81 bikes on Sept, 1988 (#12-012-99 (2323) according to my Clymer manual) for warranty replacement of the diode board if the
model had a black electrostatic dip paint finish on the timing cover. The symptoms identified were melted solder joints on the board, low battery charge rate and/or partially glowing GEN light. But, we may as well check that perhaps we can "fix" the problem (if it isn't bad solder joints and is simply bad grounding at the diode board) by cleaning up any corrosion that you see on all the mounting/grounding points and tabs where the wire plug onto the diode board. Check that all wires that plug into the board are not pinched/kinked or have worn-through insulation, loose fitting contacts etc. Clean all these contacts with some emery cloth or electronics contact cleaner and an old toothbrush. Make sure things are dry before you reconnect and try to fire the ol bike up.
As for the alternator parts - yes indeed, those brushes should be fine at that length. If your volt/ohmmeter has a low resistance scale, switch it to that scale (it might say something like "200 Ohms Max" or similar, or maybe not. In any case, we are going to be measuring some very low (small) resistances when checking the alternator, and we want to make as accurate a measurement as we can. More expensive meters will simply autorange/select the lowest/best display range - not sure what you have for a meter, but anyways....
The resistance measured on the rotor between the slip rings (brushes not touching rings) should be between about 3.0 and 3.8 ohms. If you measure more than 4 or 5 ohms, or less than 2.5 ohms, then there may be a problem with the rotor.
The resistance of the stator windings should be more than 0.5 ohm and less than about 1 ohm if your bike is at least a 1977 model (which it is). This is measured at the multi blade electrical connector that is wired to the stator coil windings.
If these resistances all check out OK, I'd clean up any/all terminals that wires plug into, clean the slip rings with emery cloth and electronic contact cleaner or isopropyl alcohol, dry and reassemble. If after doing this and cleaning up any corrosion, etc on the diode board, put all the electrical system back in place and start the engine.
If you still aren't getting proper charging voltage, there is either a bad wire connection somewhere or the diode board is indeed in need of replacing, I think. It seems
that we'd already eliminated the voltage regulator from the list of problem suspects, and we know that your GEN light bulb is working... others may have other opinions/input to help you out..
Best of luck ! Don't despair - you can very likely fix this, and you'll be very proud when you do !
Also, if you are not already familiar with the internet-wide famous "snowbum", he has a website with very good tech info on all things about these bikes, though his writing style is quite wordy and rambling, there are some 'gems' in there.. Here is a link to alternator/charging system troubleshooting on his site:
http://bmwmotorcycletech.info/trbleshootALT.htm
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Some of the wires coming out of the engine case that plug into the diode board were pretty chewed up. How do I replace these? Do I have to (gulp) crack the engine??
I tried picking at the obviously corroded wire heads on the diode board and female receivers coming from the engine with a set of those sharp pointy pics that look like they belong in the dentist's office. I thought that would do it but maybe not. I will try with the emory board and electrical cleaner. I think I lost my metal toothbrushes when I moved.
Also, some of the wires on outside of the alternator itself were pretty chewed up. How do I replace them? Just tear and re-soder? Is it that brute??
I'm determined to fix this bike if its the last thing I do, dammit. At this rate it will be the last thing I do before winter, anyway. Maybe I'll get to ride once before it starts snowing. :-[
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No sir, i don't like it, but it still needs to be tested per procedure in the manual.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi101.photobucket.com%2Falbums%2Fm70%2Fmrridden%2FDiode_Board-1.jpg&hash=78f805c95ee6de76e908c3bfd3482c81c4379074)
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Do you think the wires are actually bad enough to be shorting out? I wonder what chewed them up. If I remember right, the other (engine) side of the diode board is under the starter cover, which is held on by only two bolts. You can remove that and see the inner side of those wires. That's not the inside of the engine, which would be a very bad place for wires. Replacing them would probably be a pain though.
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If you choose to remove the front engine/starter cover, BE SURE TO DETACH THE NEGATIVE BATTERY CABLE FIRST! A misstep with a wrench or screwdriver can generate lightning bolts. :'(