1983 BMW R100RS Rebuild: Project Index

Introduction

I retired at the end of January 2015, and in preparation, purchased a 1983 BMW R100RS motorcycle for my third rebuild/restoration project.  I figured I ought to have a motorcycle project out in “Brook’s Garage” to help orient me to my new life-style.

DISCLAIMER

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Please be advised that there is no representation of the accuracy of any of the information presented on these web pages relative to BMW motorcycle maintenance or modification and that the material is presented for information purposes only. In no case will I be held liable for injury or damage (consequential or otherwise) resulting from or arising out of alterations you make to your motorcycle. The reader should recognize that motorcycling is a dangerous activity that can result in injury or death, and that the alterations portrayed on these web pages can and will change the behavior and performance of your motorcycle, possibly with fatal results. You are encouraged to seek qualified assistance before undertaking any of the procedures outlined here, and are here by notified that, should you decide to proceed, you do so at your own risk.

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Background

The R100RS was an innovative motorcycle when BMW introduced it in 1977.  I loved it when I first saw one, and it’s been on my list of candidate project bikes since I finished the restoration of my wife’s 1973 R75/5 on July 4, 2014.

It was a snowy day in January when I first went to look at the bike with a fellow Airhead who owns a 1984 R100RS.  The Craig’s List photos showed it outside, but when I arrived it had been put in a garage. The owner said he bought it for his significant other, but she decided it was too much for her “first bike”, so it hadn’t been ridden and they decided to sell it.

Hidden in the Back

1983 R100RS Project Candidate

It came with saddle bags, some spare parts, a BMW tank cover, a Clymer manual, some parts catalogs, various registration certifications, the original owner’s manual and the original tool kit and tool box with the rubber cover.

Extras Included

Some Extras Included Plus the Side Panels in the Small Box

The bike had 83,382 miles and a BMW MOA sticker on the rear fender mud guard. I took that as a positive sign; at least one owner was vested enough in owning the bike to join one of the BMW motorcycle owners groups. I got the VIN number and did a search to see when it was built and found the date was February 9, 1983.

I mulled it over and a couple days later made an offer a bit below the listing price and arranged to pick up the bike on the following weekend.  I enlisted the aid another ABC member and we used his pickup truck to get the bike to my work shop.

Loading

Loading it Up On a Cold Morning

 

Unloading

Unloading at “Brook’s Garage”

 

Bike & Bags

Bike and Bags Ready for Project to Begin

Project Pictures

You can find the all the pictures for the project here on my Flickr account:
–> 1983 BMW R100RS Rebuild

I’ll add to this collection as I document the project.

Rebuild Procedures Index

This section provides links to write-ups about how I do the work on the project.  As in the previous R75/5 restoration project, procedures are organized by the parts fiche numbering system BMW uses. This helps organize the content so it’s pretty easy to find any procedure you are interested in.

00-General

11-Engine

12-Engine Electrics

13-Fuel Preparation

31-Front Suspension

32-Steering

46-Frame, Fairing, Cases

61-Electrical

62-Instruments Dash

18 thoughts on “1983 BMW R100RS Rebuild: Project Index

  1. Awesome find, Brook! This is just the bike I’m looking for for my next rider, so as with your last restorations, I’m sure this will be very helpful once I do.

    Good luck with it –

    Shane

  2. Hello Brook, I have been following you from Madrid (Spain) for a long time. Your restorations are the best and have learned a lot… but now, I am the proud owner of a BMW R100RS ’81 so I am going to follow your steps very very close… Thank you for your fantastic job¡¡¡¡

    • Hi Sergio,

      Thank you for the kind words. I was in Malaga just a week ago where I started on a motorcycle tour of Morocco.

      I hope to post some more write-ups on work I’ve done on the R100RS soon. Stay tuned.

      Best.
      Brook.

  3. Hi Brook, my name is David, I live in Cape Town, South Africa. I came across your site while searching the internet for interesting articles on the R100RS. Your site is a goldmine and I have bookmarked it for future reference.
    I have been riding BMW air heads since 1974 and since then have owned numerous R models as well as the K, G, and C series. Currently I own a R1200GS, a R1200S and a R100RS.
    The RS has been one of the bikes that I have always wanted but strangely never owned until finally I bought an ’82 model with 60,000 miles on it. The bike was tired and in need of a refurbish. No time was wasted and the bike was stripped completely and re-painted, parts re-furbished and then reassembled with new parts where necessary.
    I have just bought a 1984 R100RS with only 5,000 miles on it. The bike rides like new and the overall condition is very good. As the bike spent most of it’s life in storage, it just needs a service and a good clean. I am in the process of getting it road legal and hope to be riding it regularly.
    Unfortunately the ’82 has to go as there is not enough room in my garage for 4 bikes.
    I look forward to new posts on your site.
    Regards
    David

    • HI David,

      Thanks for stopping by and the kind words. My wife and I have good friends in Cape Town. We’ve also done a motorcycle tour from Cape Town along the Garden Route to Port Elizabeth and then returned through the Karoo via Stellenbosch back to Cape Town. We enjoyed the country, people and food.

      Yes, I understand your “addiction”, as my wife and I currently have six BMW at our place. Four are airheads and I have both a 1977 and 1983 R100RS. I just started a rebuild/restore of the 77 R100RS so I’m learning more about the first year RS.

      And, with spring coming round, I’m sure you are looking forward to summer riding weather. 🙂

      Best.
      Brook.

  4. I’m preparing a rebuild of a 1980 RS, I live in Summit County but will be doing the work in a garage I rent in Denver. Would love to meet you and buy a coffee or a beer to pick your brain. Thanks.

  5. Hello, Brook!

    I find your articles very interesting! 🙂

    I too have a 1983 BMW R 100 RS. And I guess I’d have to do about the same jobs on my bike, sooner or later. I’ve had the bike for two years now, mileage is currently about 100 000 km, but I hope to be able to drive it for a long time. It is still in good condition, so it should be possible. Best bike I’ve ever driven, by far!

    Right now I’m struggling to change the fork oil and it seems I must remove the handlebars to get access to the filler-bolts …
    🙁

    And then the exhaust-pipes, in order to get access to the oil filter …
    :-p

    Anyways, nice website, and please keep up the good work!

    All the best,
    🙂
    Morten, Vestfold, Norway

    • Hi Morten,

      It’s nice to hear from you, and all the way from Norway.

      The oil cooler added some complexity to a routine maintenance chore; changing the oil & filer. While you are there, you will want to verify the space between the oil filter cover and the edge of the metal oil canister as I show in one of my documents, so you have the proper gap to compress the white o-ring correctly.

      Enjoy the bike and the ride.

      Best.
      Brook.

  6. Hi, Brooks!

    Sorry to bother you again.

    I checked the space between the oil filter canister and the cover as you said, and they were OK. However, the white O-ring was situated somewhere between the paper-part of the filter and the canister side, and, obviously, wasn’t doing much good there. 😉 There was also a small, slightly deformed, black, o-ring (round in profile) situated at the base of the long tube sticking out from the middle of the canister bottom.
    I removed that, as it appeared to be a left over from earlier times, and really shouldn’t be there at all (the square o-ring fastened to the 2-part, hinged filter really should be enough in there?).

    There was also a thin metal shim on the edge of the canister, and a square-profiled, black o-ring in the middle, between the filter itself and the cover. And then a black (paper?) gasket around the edges where the cover joins the engine casing. I just left that in place.

    I also checked the ball valve in the inside of the canister, it seemed OK, firmly seated in its place.

    I then replaced the old (hinged) filter with a new one (also hinged – part number ending with -575), and put the thin metal shim back in.

    Then I took the old white (round) o-ring, and a new black (square) o-ring that came with the new filter, and put put them both onto the face of the cover (the white o-ring with the rounded side towards me, i.e pointing away from the cover – the other side has two small grooves in it). I got this from:
    http://www.largiader.com/tech/filters/

    Then I put it all back together again. There was a small gap between the cover and the engine casing of 1-2 mm until I started tightening the three bolts. Then it closed up nicely all the way around.

    Does this seem correct to you?

    I have also read Snowbum’s (rather lengthy) article on this, as well as
    http://www.largiader.com/tech/filters/canister.html
    I think it should be right now. But I’m not sure.

    The info from the Clymer manual wasn’t very useful (I’d say confusing), and my own Owner’s manual proved to be absolutely useless on this subject.

    I wish there was somewhere I could turn to in order to get accurate information on how to do things on MY bike, as there are so many different models and variations out there. Like a forum for post 1981-82 R100RS, or something. Then I wouldn’t have to bother you about matters like this. 😉

    Sorry again, and thanks for your patience!
    🙂

    Best wishes,

    Morten, Norway

    • Hi Morten,

      There has been a lot written about the white o-ring and the problems getting it to seal correctly with the wide range of canister depths found right out of the factory. I spent a lot of time reading several discussions about how to properly measure the gap between the filter canister and the top of the engine block, figure out how many shims to use, and if I should use the cover gasket or not. Getting this right is CRITICAL to ensuring you get oil pressure at all times.

      I found Oak Okalsen’s formula the most straight forward procedure and I include his formula for deciding IF you should use a cover gasket and how many shims to use in the following document:

      11 BMW 1983 R100RS Diagnose Intermittent Low Oil Pressure Light

      From your description, I don’t know if you should use the cover gasket or not. It depends on how deep the oil filter canister is inside the engine block. If I recall correctly, you only add the gasket if the gap between the top edge of the canister and the top of the block is too shallow. It you add it without checking the canister depth using Oak’s formula, you can reduce the sealing force on the white o-ring enough that it will deform when it sees the high oil pressure created when you first start the bike and leak.

      I ALWAYS replace the white o-ring and the black square edge o-ring every time I remove the oil filter cover. They are cheap and the engine is not.

      As you note, there is no “one” source of reliable information, but there is a forum, the micapeak airheads forum, that several long time airhead mechanics monitor (Bob Fleischer, Tom Cutter, Bud Provin, Anton Largiader, in particular) as well as many very knowledgeable airhead owners, who freely provide their knowledge. It is a reliable source for good advice and if you haven’t subscribed to it, I highly recommend it.

      –> http://lists.micapeak.com/mailman/listinfo/airheads

      I hope this helps.

      Best.
      Brook.

      • OK, thanks a lot, Brook!

        Very helpful.
        🙂

        Well, it seems I’ll just have to take another and even closer look at this 😉

        Anyhow, I’m sure it will be better than it was before, when there was NO white o-ring there at all, as it was (dis)located and found INSIDE the canister, about in the middle of it, between the canister side and the oil filter itself, as I discovered when I took off the cover to change the filter …!
        And the bike has probably run for at least two seasons like this, and run very well too!

        Thanks also for the link to the forum; I’ll check it out and hopefully get some good help there in the future.

        I really appreciate your friendly and helpful attitude!
        🙂

        All the best,

        Morten

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