Need spiritual help on resurrecting my old lady...

Discussion in 'Airheads' started by Barbadi, Apr 19, 2012.

  1. Barbadi

    Barbadi Been here awhile

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    My R 80 g/s died suddenly while running perfectly. We went over a big speed bump and the engine just died. The battery is fine, the starter motor turns fine, the lights, horn etc come on but the lady stands as still as Greek economy. I yanked and spray cleaned every cable and cable port I could reach, still nothing.

    Ignition coils (latest bmw version) I measured gave a reading of 0,96 ohm for primary coil and 12,68 Kohm for the secondary coil. I 'm not really good with the multimeter and electronic stuff (I just tried to follow haynes guide lines as best as I could) so I don't trust my findings to indicate that I should fork the money for a new coil with any certainty. I just checked it cause adv wisdom states that when in bad weather or bumps airheads die of bad coils. Haynes states that the resistances should be between 1,15 -1,32 ohms for primary and 7,50 kohm -9,15 kohm.

    I also guess that it couldn't be any spark plug or spark plug caps or their leads as it would be rather unlikely that they both fail together so no sign of engine poping goes on. Once I had a cut spark plug cable and the machine started poping with the one of the two cylinders. My wiring loom is also fairly new, I changed it a few years back.

    Any ideas? Suggestions? Old airhead mandras?

    What should be the proper priority I give to start suspecting components?
    #1
  2. mykill

    mykill odd

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    From a bump to dead, there is a good chance it is a bad connection.
    Have you fiddled with the kill switch? A very likely culprit.
    Do you have power to the coils with the key on? if so, check connections to the ICU and bean can. If not, trace back to ignition switch.
    This will be simple.
    #2
  3. Barbadi

    Barbadi Been here awhile

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    Is there a possibility to have indicator lights on and starter motor working and at the same time the kill switch off?
    #3
  4. Solo Lobo

    Solo Lobo airhead or nothing

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    Do you have spark? I am going to guess no
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  5. hardwaregrrl

    hardwaregrrl ignore list

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    Certainly sounds like a bad connection. i just had this happen and it ended up being a broken wire to my igniton switch. I bet it's something real simple, and cheap to fix.
    #5
  6. Barbadi

    Barbadi Been here awhile

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    Well I tried to find any broken or loose wire by eye and hand inspection but zero effect. I also sprayed everything with electrical contact spray. Nothing. Now I need some advice on where to start looking first since my electrical power is there and my starter motor is turning. How do you recoment I check for spark? Should I just pul out the spark plug cable or the hole spurk plug with the cap and cable and press the button?
    #6
  7. LonerDave

    LonerDave Been here awhile

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    To check for spark: remove plug, reconnect wire, ground plug to engine (touch it to case), crank and see if spark jumps gap in plug. Of course, be careful not to make your self "part of the circuit".

    Or spark testers are available for $10 or so. I have one that is simply placed next to the wire and senses current through induction. Easy-peasy.
    #7
  8. Barbadi

    Barbadi Been here awhile

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    Thanks for the "how to". When I was young we did it this way on jap bikes but I 've heard that doing it to beamers causes it to fry some circuit or something. I 'll give it a go.
    #8
  9. Wirespokes

    Wirespokes Beemerholics Anonymous

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    You won't fry anything if the plug is grounded - touch the threads to the cylinder head.

    To check for voltage at the coil - connect the voltmeter with black lead to battery minus (ground), and red lead to coil terminal #15. With ignition turned on you should see 12.7 volts. Do this quickly because the ICU will turn off after a few seconds once it detects the engine isn't spinning.
    #9
  10. LonerDave

    LonerDave Been here awhile

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    I think the danger of frying something (the coil) comes when the impulse doesn't have a place to go. Grounding the plug allows it to go to ground.

    Also believe that high-energy ignitions are more susceptible to this type of damage, but don't know if your bike has one. 1980 G/S?
    #10
  11. Barbadi

    Barbadi Been here awhile

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    Although its not polite to speak of a lady's age, mine is a 1984 G/S. Its voltage regulator is the latest type, as is the ignition coils and diode board. I 've changed them through the 11 years I rode her.
    #11
  12. OZbeemer

    OZbeemer Been here awhile

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    I know it sounds too simple, but did you check how well the connectors at the battery are connected to the wires? I once stood on the side of the road for over an hour chasing a gremlin that turned out to be a bad connection between wire and terminal on a battery connection.
    #12
  13. Barbadi

    Barbadi Been here awhile

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    First think I checked as I had a visit from the same f@cken gremlin three years ago. :D
    #13
  14. Barbadi

    Barbadi Been here awhile

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    well remember that I had no spark?

    I performed all the tests in the Haynes manual and I could not point my finger to the guilty part. I had changed my ignition coils anyway -on the old airhead mandra "if your sparks are gone its the coils"- but stil no sparks.

    So I ordered a ignition control unit from motorworks and -drumroll- we got sparks! BUT!

    The old lady still is semidead cause as soon as I had sparks I tried to get her to work and the mfckn starter motor gave up on me draining all my current.

    In the process it killed my jumper battery kit also and did a trick on my cars -Citroen C3- battery.

    The starter demands over 3000 rpms on the car to start revolving pretty slow, the bike poped and banged a few times and it finelly worked -caughing huge clouds of black smoke- but it died after seconds and never had any electrical juice again to make roar again. I took the starter motor -Bosch 0.001.157.023- expecting to see the brushes minimized.

    The brushes seem fine and they are over 12,5 mm in length BUT the commutator that the brushes are rolling on is on a diameter of 32,8 mm. The Haynes manual says the minimum diameter should be over 33mm.
    Is the armature junk material?
    Has anyone measured his armature?
    Should I buy a single armature, or a hole starter motor? (its a 1984 item after all). But I 'm in Greece and the postal fees of a 6 kilos item are pretty bitter on my limited budget. Any cheap euro sources?

    Please don't turn this post in a Bosch vs Valeo stand-off, (not to mention the Denso saga) IF I have to go to a new starter altogether I ll go with the cheapest I can get, Valeo probably.

    BUT I need info on a possible starter motor rebuild.

    I am unemployed and Greek. Cheapest alternatives will be appreciated. Thanks!
    #14
  15. Barbadi

    Barbadi Been here awhile

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    I, ve done every check in the Haynes manual. No go and no spark until I changed the ignition control unit, -as haynes suggested when something goes to the grey area- and the sparks where back. :deal

    I supposed that it would be clear and profound that since I did all the haynes tests I did it with a multimeter. What else would I checked electrical components and circuits with? My dick and a small 9V battery up my butt?:norton

    Plaka I appreciate your time and effort but if I had no idea of all the thinks you wrote, the only think you should have said should be "keep away from the bike, call the truck and take it to the shop". But you seem to enjoy the old preacher style so I won't spoil it for you. I just wish you also knew what is the proper commutator diameter, instead of the military vehicle's voltage. I'm not trying to fix a Hammer here. And yes I 've concluded my army service.

    Of course I 've tested the starter motor on the bench. It doesn't do shit. Not even with the car's battery. The solenoid works ok alone and unpluged from the starter, but the starter motor works only with the battery on the car and the rpms up, so I guess it needs too much current.

    I 've checked also that there is no continuity between armature and commutator.

    So to my simple knowledge the question is why and how to fix the current consumption. Cheap. If I am about to give a 100 bucks for an item I might as well go hunting for either a used secondhand starter motor or a chinese/french knock off.

    But first thing first. So I 'm going down to the shed and dremmel down these commutator lines deeper and see what happens. Thanks anyway. Anybody else has any other idea?
    #15
  16. Barbadi

    Barbadi Been here awhile

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    anyone else has any other suggestions?
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  17. AlpineRAM

    AlpineRAM PartsChaser

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    My take on it- Unemployed in Greece means you have much more time than money on hand. So use the time you have to avoid spending the money you don't have.

    I would split the problem in 2 separate parts- Starter and Not running right.

    Since you already have removed the starter you could put the bike together and try to push start it. (Take care about the big + cable for the starter not making contact with anything that it should not contact, it is unfused and can incinerate your bike and make the battery explode and spill acid over your private parts)
    If it runs OK you know that you have your ignition sorted, if not you know that you will have more work.

    I do not concur with Plaka's theories on DC motors, but he is nevertheless right in telling you to take a look at the contacts of the solenoid (or Bendix), all the copper contacts in there should be really nice and both contacts should be the same thickness. (Usually just one gets burnt off)
    The armature diameter can become critical because the brush contacts more "fields" on the armature at the same time than it was designed for. As a quick and dirty test you can file off a little bit from each brush so that only a smaller section contacts the armature. (That is not intended as a permanent fix!)
    If this helps it looks like time for a new armature. If not, your problem is somewhere else.

    Since your tests point to a lot of energy going into the starter and not much coming out as mechanical energy, there must have been a lot of heat. Try to find out where it gets hot first and investigate.


    HTH

    AlpineRAM

    PS: If you need some Bosch parts let me know, I might have them around.
    #17
  18. Barbadi

    Barbadi Been here awhile

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    Thanks, I was suspecting it has to do with the armature's "d", since it turns but after sucking all the juice out of the car system, and its under proper specs.

    Problem is that the bike has been sitting for 3 years now, and from my first attempts the lady made clear that she won't start that easy. Especially without the starter motors help.

    Anyway I will see if I can jump start it with help from friends, and thin a little the brushes. And spot the hot points. You were very helpfull.
    #18
  19. Barbadi

    Barbadi Been here awhile

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    Alpine you were dead on the subject!

    Most of the commutator segments were around 4,5 mm wide, but the brushes were almost 7mm. I dremmeled the brushes to a thinner 4,2 mm and put the starter motor together and it works fine!

    But the lady still has no pulse! Now the spark is gone from the plugs, although after changing the ignition control unit I had sparks. Now the starter turns but in vain.

    Do I have a circuit gremlin or I fried the second icu?
    #19
  20. AlpineRAM

    AlpineRAM PartsChaser

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    Thanks for the update!
    I would not continue running the starter like this if you can afford either a new one or a new armature...

    Since you did a lot of different things on the bike already I would suggest that you start over with the basics. Since the starter works we know you have juice in the battery, you have an at least partially working ignition switch and you have engine ground.

    My next step would be to check all the suspect connections again, especially coming from the ignition switch to the ICU. (And the test for voltage on pin 15 of the coil)

    I don't know how you would have killed another ICU since you were advised on grounding the spark plugs... so let's hope that it's just a lose cable or something trivial like that.
    Maybe you can retrace the steps that led you to determining the ICU before your starter gave up...

    Cheers!
    #20