Results 1 to 10 of 10

Thread: 1980 r100rt

  1. #1
    Registered User
    Join Date
    Mar 2012

    1980 r100rt

    Hello to all members i am new to the forum. I have just bought a high mileage 1980 R100RT, my first BMW. Has 85k on the clock
    I am told that the bike has a charging issue, that is inherent in these models.
    The final drive needs 're-conditioning'
    and the valves need to be adjusted.
    I imagine that there is a solid state, electronic upgrade I can buy to take care of the charging issue
    I would also think that with the manual I can adjust the valves, hopefully take care of the drive as well .
    Any advice at this stage would be greatly appreciated , thanks for any input and all the best , regards Steve Heaney

  2. #2
    Registered User
    Join Date
    May 2006
    Here is some reading to help you get started.

    As far as electrical, ditch the charging system for the Enduralast 350 Watt system. It is bulletproof as long as you solder the wires.

    With the stock system assuming all parts are in good condition use an adjustable regulator to set high RPM voltage at battery to 14.4 volts so the battery can charge.

    Use a sealed AGM battery to eliminate dealing with acid.

    Here's hoping you enjoy wrenching and riding your new bike.
    Last edited by 35303; 01-06-2013 at 04:53 AM.

  3. #3
    Registered User toooldtocare's Avatar
    Join Date
    Mar 2008
    DeLand Florida
    First, welcome Steve. 85K is not that many miles, although time to do a bit of TLC may be in order. No need to do anything other than troubleshoot/clean/repair the charging system. It puts out enough amps to satisfy most people, those that do not run a lot of powered clothes. There are upgrades, but in my nearly 30 years riding airheads I have not found the need to have one. As far as the rear end, also simple to work on, but you need a couple of special tools, and adjusting valves on an airhead is very easy.

    First thing to do is get a service manual. For you, I would recommend a Haynes because it is easier to understand than some of the other ones. It is not as detailed as a Clymer, but should get you started. Second, find someone that also owns an airhead, or get involved with the Airhead Club. They have tech days once or twice per year in various cities and the people there would love to help you out. Third, do not believe everything you hear about airheads. They do require maintenance, like everything else, but they are not money pits either just because they carry the BMW logo. And even though your bike is over 30 years old, parts are easy to get.

    Enjoy your bike. I sold my last airhead last summer, but I have another on the radar and hope to have by April.


  4. #4
    Registered User
    Join Date
    Mar 2012


    Thanks Wayne and 35303, the advice is much appreciated and will be followed.

  5. #5
    Registered User 88bmwjeff's Avatar
    Join Date
    Aug 2004
    Walnut Creek, CA
    Here's a couple other things to be aware of.

    Whether the repair manual is the BMW, Clymer or Haynes, there's errors in all. So, be careful, check online and ask. The four long bolts (on each side), which hold the cylinders and heads on, can be pulled from the case (bottom end) rather easily. So, when it comes to torquing the head bolts, the general consensus seems to be 25 ft-lbs.

    There are several (if not numerous sites) out there with advice. Here's Snowbum's site, who has lots of tech articles.

    With regards to the charging system, it's probably a good idea to purchase Motorrad Elektrik's Charging System Manual (see link below). It explains the charging system very well and provides some troubleshouting tips. At least so I've been told. This area is above my expertise and I've been lucky not to need to do any troubleshooting on it yet. I would do a search on charging systems, since there's always one or two a year needing help. You will need a special tool to remove the rotor.

    Best of luck and enjoy your RT.
    Jeff in W.C.
    1988 R100 RT (the other woman)
    "I got my motorcycle jacket but I'm walking all the time." Joe Strummer

  6. #6
    Registered User
    Join Date
    Dec 2007


    Join the Airheads. Find the Airmarshal in your state and attend a tech day.
    La. Airmarshal

  7. #7
    Registered User lkchris's Avatar
    Join Date
    Mar 2003
    Albuquerque, NM
    It's not so much an "issue" as it is a "feature," i.e. the charging capacity by today's standards is limited.

    Practically speaking, you'll likely have no problems, as the system is not going to self-destruct. Alternator may need brushes is about all.

    The bike was designed in the era prior to driving with headlight on all the time, and if it's legal where you are and you do lots of short trips, fitting a "european" headlight switch is a useful thing.

    I rode my '84 R100RS from new for 28 years and never felt the need to upgrade the charging system, and I'd fitted heated handgrips and often used heated clothing liners, etc. I even fitted auxiliary lighting, although I did it BMW's way, i.e. only one extra light working at one time. No problems ever.

    Like any motorcycle I think, but for sure BMWs, following the practice that if the bike's home the trickle charger is connected is a best practice. New alternators, zooty batteries, etc., don't change this.
    Kent Christensen
    '12 R1200RT, '02 R1100S, '84 R80G/S

  8. #8
    Registered User PAS's Avatar
    Join Date
    Jun 2011
    N.E. Ohio
    Can you give us more details about the statement "the final drive needs reconditioning" Hopefully it's not the wheel/drive splines.

  9. #9
    Hopelessly lost subagon's Avatar
    Join Date
    Apr 2008
    Plant City, FL

    If by chance you're located in Florida, there are 2 tech days this month, one next weekend.
    Mike Barfield - Plant City, FL
    '07 R1200 GS - '75 R90/6 - '93 R100GS PD - '71 R60/5 - 2 X '73 R75/5 LWB - '83 R80 ST

  10. #10
    Registered User
    Join Date
    Mar 2012


    I greatly appreciate this input. The bike has not arrived yet from Chicago, Shipper due in a week or so.
    To Subagon, thank you, I am indeed in Florida I live in Fort Lauderdale,
    I don't think I will be up and running for this first tech. day maybe the next.
    To PAS, the P.O. had a quote for the 're-conditioning' of the drive for $250 or thereabouts from classic BMW dealer Chicago. So it sounds like some grease and a couple of gaskets, as you say 'hopefully' . I picked up on that issue in the ad and asked him if he was having any clunks, he said no. We will see , thanks for your input.
    To lkchris, good to hear this I will keep the bike simple and original if that makes sense. Thank you.
    To edwarddieck I have joined the airheads, no idea at the moment who my florida airmarshall is , i think maybe subagon will know.
    To 88bmwJeff, yes I have ordered the Clymer and the Haynes manual. I am very impressed with snowbum what a wealth of information. Thanks for the heads up on the charging system manual I will investigate.
    best regards to you all , Steve

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts