r100 help!!

Discussion in 'Airheads' started by trodgers, Sep 25, 2012.

  1. trodgers

    trodgers Adventurer

    Joined:
    Jun 11, 2012
    Oddometer:
    35
    Location:
    Spokane, WA
    Hey guys,
    I recently have purchased a r100. To start things off wrong, the bike was titled as an 84 but it looks like it is a 79. I have a rear brembo and front dual disc. And my Clymer pointed me in the dirrection of a 79 from the vin number. This all being said, I have gotten the beast running and have taken it out a few times. Its a fun bike! Its also my first airhead. There are a few problems that I have though...

    #1: The rear brake light is always on. I have an electrical connector above the battery that has a burnt out prong on the male and female side. I think this is my brake light problem. BUT i cant find the part number for this connector.

    #2: The starter doesnt always turn over. It seems like its a ground issue, but I might be wrong. What happens is that it will turn over when its cool-er. On occasion though, I will try to start it when in neutral, and nothing will happen. I dont know what is wrong. Is there a way to test my starter relay to rule it out?

    #3 My neutral light is out. Not the biggest thing but BMWs are oddly wired and could affect something?

    PS this is going to be torn down in about a month for my cafe build...
    #1
  2. cb350nyc

    cb350nyc Adventurer

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    You in the right direction...

    Post some pics!!
    #2
  3. nhmaf

    nhmaf Been here awhile

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    Oddometer:
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    Location:
    Barnstead, New Hampshire USA
    There is a neutral switch on the bottom of the transmission, near the rear engine mount on the left side with 2 wires that go to it. If you have a break in the wire(s) or they are pulled off, your neutral indicator will not light (assuming neutral indicator bulb not burned out or miswired), These switches also can have a habit of breaking. There is also a diode (either hidden inside the headlight or else wrapped up in the wire harness) between the clutch engagement switch (at the clutch lever) and the neutral switch, so that either one going to ground will ground a pin on the starter relay and allow the starter to turn when the button is pressed.

    If you neutral light doesn't work, but you can start the bike with the clutch lever pulled in, at least part of the circuit is still working. You need to determine if it is a bad wire connection or bad neutral switch (and/or bad bulb) that is causing your neutral light not to work.

    I'd recommend getting a HAynes manual to further aid with your routine maintenance on this bikes. They aren't hard to work on, but they are different. Each manual has its strengths, and weaknesses. And both have some errors & omissions, too.

    The starter might be binding up when things get hot - no one bother to check on them and do the routine/periodic cleaning of the starter bendix gear assembly every 10-15 years or so. The grease hardens and with dirt and grime, can bind up. Or you might simple have a loose connection in the relay circuit, or down at the starter motor itself (under the top cover on the engine. The BOSCH starters also aren't the most efficient starter motors, but they are very rebuildable, and there are aftermarket replacements if it really needs to be replaced. Chances are that it just needs some attention/routine maintenance though.

    If the VIN/frame serial number indicates you have a 1979 bike, chances are that is what you have - many parts are interchangeable or retrofittable with no or slight modifications. Check for a serial number on the engine near the oil fill hole and tell us if it matches the digits on your frame serial number on the right side near the steering head.
    #3
  4. trodgers

    trodgers Adventurer

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    First off, i want to apologize for the frequency of my response.

    I took some time and tried to investigate on my issues with the bike. I took the cover off to access the starter. It had spider nests in it so I feel like this needs to be attended to. BUT the bolts that hold the wire brace seem to be inaccessible. The neutral switch has two wire that appear to mount under the transmission. are both of these grounds? One of them has come loose and I was wondering if it needs to go there or if I could ground it where ever. there is a lot of oil and grime on this part of the bike.

    The vin number matches the engine vin (YAY). In my Clymer it notes the VIN to be a 79-80. Since its in the earlier of the VIN numbers mentioned, I believe its truely a 79.

    Does the Hayes do a better job than Clymer? I would hate to waste my money on another manual if its not of much help
    -Tom
    #4
  5. R100RT Mark

    R100RT Mark Been here awhile

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    Feb 19, 2011
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    Location:
    Georgia, USA
    Quickest/simplest way to cross check VIN model/year etc. is to plug it into one of the online parts fiche. MAX BMW gets a lot of credit for having a comprehensive system: http://www.maxbmwmotorcycles.com/fiche/fiche.aspx


    Haynes better job? NO. Different and oftentimes a highly valuable different perspective. YES. Buy both.
    #5
  6. disston

    disston ShadeTreeExpert

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    It's recommended to have both manuals. Some things covered in one not covered in other. Some things covered in both are worth having two perspectives on.
    #6
  7. DaveBall

    DaveBall Long timer

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    Vancouver Island
    Definitely remove the spider's nest carefully. You may have to coax the daddy spider out, he is usually named Herman. :rofl

    As to the Neutral switch. You need to attach both wires to the switch. If one of the tabs is broken off, then you will need a new switch. The first time trying to attach those wires can be a pain, due t there not being a whol elot of room to work in. I usually use a tool that I got from somewhere a long time ago. I don't know what it is called, but it works like a reverse pair of tweezers. Basically you squeeze at one end to open the other end, place the connector in the end and unsqueeze. Holds it nice andtight and can then wiggle and prod to get the connector onto the switch, then squeeze to release it.
    #7
  8. trodgers

    trodgers Adventurer

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    I believe the switch is located near the left foot peg on the side. It has a few wires connecting to it. Some of the wires come underneath the the motor and transmission and connect to someting(??) on the bottom. Does this make sense? I can take pictures when I get home tonight to help better explain this. Unless the switch is on the bottom of the motor?
    #8
  9. Rob Farmer

    Rob Farmer Long timer

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    Location:
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    The wires for the Neutral switch run behind the left side panel, down the frame tube and then under the gearbox, the switch is earthed using the brown wire that bolts to the gearbox bolt near the gear change. it's always wirth pulling the connector under the side panel apart a few times to make sure the connection is made but I suspect your neutral switch is scrap.

    The rear brake light switch is behind the passenger foot peg mounting plate on the right side of the bike. If you peer down from the top you should see the rubber cap for the switch. There's an adjustable locknut that needs tweaking to get the switch to work correctly - the fact that it's on is a good sign.
    #9
  10. trodgers

    trodgers Adventurer

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    Thanks Rob! Awesome info!
    #10
  11. trodgers

    trodgers Adventurer

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    nooB question... How do I post pictures? I thought the insert image icon with a Flickr account would work, but its not :cry
    #11
  12. Hedge36

    Hedge36 My e-penis is huge.

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    Drag the bike up to Anacortes for a weekend. We can go through yours using mine as a reference.
    #12
  13. disston

    disston ShadeTreeExpert

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    #13
  14. patanga

    patanga BMWAirheadsDownunder

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    Australia
    Welcome to Airheads 'trodgers'.. You'll grow to love them I can assure you. To post pictures you will need a cloud account of sorts, (e.g. photobucket). Upload the pictures there first and then copy the relevant link and embed it into your post using the global attachment (i.e. world globe and horizontal paperclip image) option in the selection line at the top of your new or edited post. Look forward to seeing the pics. Cheers.

    ____________________
    "The only reason people get lost in thought is because it's unfamiliar territory" (Joe Garcia)

    "BMW Airheads Downunder", (The Australia and New Zealand Airhead Community). "B.A.D"
    :wink:
    http://www.facebook.com/groups/anzairheads/
    #14
  15. trodgers

    trodgers Adventurer

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    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
    #15
  16. trodgers

    trodgers Adventurer

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    Above are some pictures. Now that I look at them, they are out of order, sorry about that. But there are some with the bike and some of my neutral switch.
    #16
  17. trodgers

    trodgers Adventurer

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    If I could make the bike to Antacortes, I would!
    #17
  18. DoktorT

    DoktorT BigBrowedNeandereer

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    Apr 8, 2009
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    Location:
    Chewelah, WA
    A little practice and you should be able to get some better focus, but I see a different paint scheme on the seat cowling than my 79RS. The seat itself is a custom of some type.

    Are you a rear drum or disc brake?? The T model that year was drum. The RS RT's were disc. Oak likes the 79T as the best base Airhead ever produced.

    Data plate on steering head should show month and year of production, and should also identify original spec, T/RS/RT.

    But the dark blue/light silver was only used on the RS that year.

    Looks like a 79 RS with the fairing deleted to me.
    #18
  19. trodgers

    trodgers Adventurer

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    it has disc break in the rear. I have noticed a reference to 1980 on the rear wheel well
    #19
  20. trodgers

    trodgers Adventurer

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    Location:
    Spokane, WA
    Been thinking about how to do the bike. I have short legs (30" inseam), Currently the only way I can ride the bike is with boots on. Can anyone recommend a shock(s) that allows me to lower the bike a bit? I currently have old(er) shocks that have some rust on the springs. Its possible that they are old and wont lower to where I want them.
    #20