Author Topic: 1985 K100 RS: practical rejuvenation  (Read 4637 times)

Offline uhoh7

  • Motobrick Curious
  • Posts: 16
1985 K100 RS: practical rejuvenation
« on: September 21, 2017, 01:56:53 PM »
By surprise, this 85 (made in late 84) K100 fell in my lap. I ride alot, but all backcountry. No road bike for many years. No previous "K Lust".


However, you know what they say about the gift horse......


First series of shots here show her as I got her:
https://www.flickr.com/photos/55299472@N07/albums/72157685583051894/with/36823874015/


And about 20 hours and $300 later.....
https://www.youtube.com/watch?v=Zm9xDNN4kuc&feature=youtu.be
  • Idaho
  • 1986 K100

Offline Martin

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  • Posts: 3566
Re: 1985 K100 RS: practical rejuvenation
« Reply #1 on: September 21, 2017, 08:26:00 PM »
Looks like an easy fix good find.  :2thumbup: :clap:
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Christopherguzzi

  • My first Beemer🏍.
  • ^ Proficient Motobricker
  • Posts: 126
  • It ran when it was parked........27 years ago😳.
Re: 1985 K100 RS: practical rejuvenation
« Reply #2 on: September 22, 2017, 02:53:45 AM »
There's no such this as a free puppy or old motorcycle.    :eek:   But it would seem that you are quite handy and have gotten her purring nicely for a minor investment.  Nice work, enjoy!
  • Little Canada, Minnesota
  • 1986 K75C
Christopherguzzi

Offline Laitch

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Re: 1985 K100 RS: practical rejuvenation
« Reply #3 on: September 22, 2017, 09:48:31 AM »
And about 20 hours and $300 later.....
https://www.youtube.com/watch?v=Zm9xDNN4kuc&feature=youtu.be
Is your fuel cap still mounted backwards? That might lead to water infiltrating the tank unless some accommodation was made for drainage.
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline uhoh7

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  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #4 on: September 23, 2017, 11:43:58 AM »
Is your fuel cap still mounted backwards? That might lead to water infiltrating the tank unless some accommodation was made for drainage.


It may well be backwards, TY. Somebody else mentioned this also.


I've now upgraded my starter switch:



Starter switch by unoh7, on Flickr



Starter switch by unoh7, on Flickr

Starter switch by unoh7, on Flickr


Starter switch by unoh7, on Flickr

There is a good spot on the coil cover, and last shot shows cable routing. Basically all you need: high amp switch, heavy gauge wire, two short lengths. If the bike will push start and runs fine, and the starter is clean and responds to a jump, then a new starter switch is pretty easy as you see.
  • Idaho
  • 1986 K100

Offline The Mighty Gryphon

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  • Posts: 4118
Re: 1985 K100 RS: practical rejuvenation
« Reply #5 on: September 23, 2017, 12:02:32 PM »
Wrapping the wires around the screws on the switch is the sign of poor workmanship.  Sooner or later the strands will get loose and cause problems.  Get some crimp on ring terminals and do the job right.  You might also want to invest a few extra dollars in tinned wire.  The best place to get it is a marine supply chandlery where it is sold for use on boats. 
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '92K100RS White, '94 K75S Dakar Yellow
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'94 K75S "Cheetos"
'91 K100RS "Moby Brick Too

Offline Blue

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  • Posts: 83
Re: 1985 K100 RS: practical rejuvenation
« Reply #6 on: September 23, 2017, 12:20:38 PM »
Speaker wire.  Nice.
  • Stovepipe Wells CA
  • 1995 K1100RS

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5940
Re: 1985 K100 RS: practical rejuvenation
« Reply #7 on: September 23, 2017, 01:59:15 PM »
  • Along the Ridley in Vermont.
  • 1995 K75T 68,000 miles
I wept because I had no radials until I met a man who had no splines.
http://www.motobrick.com/index.php/topic,296.msg53303.html#msg53303

Offline BrickMW

  • ^ Proficient Motobricker
  • Posts: 126
Re: 1985 K100 RS: practical rejuvenation
« Reply #8 on: September 23, 2017, 03:02:49 PM »
Speaker wire.  Nice.


I wonder what amperage it's rated for?.?.. I wonder what temp it's rated for?.?.. I wonder if there's a fuse inline?.?.. I wonder if there's a fire extinguisher in one of those tragkorbs?.?.. :dunno


I'm the wonderer.. :hehehe
  • Huntsville, AL
  • 1986 K75c
Luft & Jager... My two favorite Meister's :bmwsmile

Offline jimboknowsit

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  • Posts: 15
Re: 1985 K100 RS: practical rejuvenation
« Reply #9 on: September 24, 2017, 08:44:00 AM »
That bike is ready to Jam


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Offline jimboknowsit

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Re: 1985 K100 RS: practical rejuvenation
« Reply #10 on: September 24, 2017, 08:45:04 AM »
Rock on


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Offline uhoh7

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  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #11 on: September 24, 2017, 01:19:52 PM »

Thanks for the input :)

Speaker wire.  Nice.
"Speaker Wire" LOL it's 12 gauge 100% copper heavily insulated with a very short distance. Insulation is flexible, and after 50 starts, 200 miles no sign of melting, but I will keep watching it. The wire seems better than the wire I found coming from the starter relay.

As to the "do it right" about using the screws to attach the wire: the switch is designed this way, and having seen soldered connections crack many a time, I considered various options and decided to go as you see. It's my ass.

What I should have done is post my proof of concept test setup so you guys could really have some kittens: I robbed a kill switch from my KTM and hooked it up. Wait here you go:



The little kill switch quietly failed on about the 20th start.

In my first post I sated clearly what is needed to do it safely: Hi amp switch, heavy gauge wire. Certainly connections should be made carefully. Many arguments about the best ways to do that. Solutions vary. I'm not hiding mine. :)

And lastly: I do not "advocate" anyone does this. Any DIY can go wrong. No promises from me about your situation. If you do, please choose auto wire if you feel safer. 12 Gauge minimum. The auto wire insulation is "supposed" to handle bends and heat better. I will keep an eye on the insulation. No signs of melting after many starts on a 200 mile ride yesterday. Also, be confident in your connections. You don't want them shaky or coming loose.

For me, it's fine. But I will post pictures of the fire ;)


Best to all :)




  • Idaho
  • 1986 K100

Offline Blue

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  • Posts: 83
Re: 1985 K100 RS: practical rejuvenation
« Reply #12 on: September 24, 2017, 01:26:23 PM »
I use electric fence wire.
  • Stovepipe Wells CA
  • 1995 K1100RS

Offline Scud

  • ^ Proficient Motobricker
  • Posts: 364
Re: 1985 K100 RS: practical rejuvenation
« Reply #13 on: September 26, 2017, 12:08:11 PM »

Some funny stuff up there about the electrics.

On a serious note regarding electrical connections:


I think the best for the post terminals pictured above would be crimp-on rings (not soldered). It's worth buying a box of high-quality crimp-connectors with heat-shrink ends. And for an even more secure and attractive finish, some heat-shrink tubing to wrap the ends and make it water-resistant.


Then you'll want to clean and lube the post terminals and rings to prevent corrosion where the metal is exposed to the elements. I use Dow-Corning, DC-4 electrical insulating compound. Some people just use Vaseline, but it can get runny at higher temperatures.
  • Carlsbad, CA
  • 1992 K75s. 2002 Moto Guzzi V11 Scura, 2003 Moto Guzzi V11 LeMans. 2007 Husqvarna TE450

Offline BrickMW

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  • Posts: 126
Re: 1985 K100 RS: practical rejuvenation
« Reply #14 on: September 26, 2017, 12:22:53 PM »

I think the best for the post terminals pictured above would be crimp-on rings (not soldered).



Looks like he used them on the other end... maybe.?.


  • Huntsville, AL
  • 1986 K75c
Luft & Jager... My two favorite Meister's :bmwsmile

Offline uhoh7

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  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #15 on: September 30, 2017, 01:47:05 PM »
I sued crimps for battery and started connection. I decided not to use them at switch. Jus my call. :)
  • Idaho
  • 1986 K100

Offline Martin

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  • Posts: 3566
Re: 1985 K100 RS: practical rejuvenation
« Reply #16 on: September 30, 2017, 03:28:01 PM »
Some people just use Vaseline, but it can get runny at higher temperatures.
I use the Dow Corning heavy high vacuum silicon grease that I bought for the K75 steering damper. I also use it under the brake master cylinder boots, under the fork dust boots, around electrical connectors.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline billday

  • ^ SuperNatural Motobricker
  • Posts: 951
Re: 1985 K100 RS: practical rejuvenation
« Reply #17 on: September 30, 2017, 05:49:04 PM »
Starter buttons whose little green cap has broken off are known to cause big problems. I forget the ins and outs but Snowbum from one of those other K-bike tribes once went on at length about it.

That bike looks like it's led a rough life.
  • New York State, USA 10977
  • 1985 K100

Offline uhoh7

  • Motobrick Curious
  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #18 on: October 01, 2017, 12:15:27 PM »
Starter buttons whose little green cap has broken off are known to cause big problems. I forget the ins and outs but Snowbum from one of those other K-bike tribes once went on at length about it.

That bike looks like it's led a rough life.


TY for that and all the comments, appreciate them.


Based on the switch condition and coloring, the bike has spent alot of time outside, probably more than one Idaho winter in the snow. If I end up keeping the stock configuration with fairing, I should just find some good controls, which the cafe guys toss all the time.


She is cosmetically beat, and had a terrible white paint job over the factory silver. Nevertheless I'm surprised at how the bike turns heads. I caused a small sensation just with a stop at the local post office.


I'm riding her every day at the moment. I'm a computer consultant in a resort town, so I have to run around alot. I have various ways to do so, and I find this new option is pretty fun. At first look at the battered saddlebags, I was thinking...do I even want to use them? Now I don't think twice but just strap them down.


"That is a very sexy bike", said one of my high-toned clients, to my surprise. In truth, it's a sexy bike to ride. There is a rawness to the whole thing. Opposite of a gold wing. There is seldom the "quiet rail" feel, since by 3K, the engine is pulsing through your body, enhanced by the laid out RS posture. Left peg leads the way into a world of buzz. I just embrace it. LOL I love the fairing, and handling seems frankly excellent. I think the fastest I have had her going is a bit over 90. Very stable, and smooth in the sense of wheel to road.


I feel like Daenerys Targaryen on one of her dragons ;)


This late 84 build is a imperfect motorcycle, even if fresh, I suspect. For one thing, the head is on the wrong side! The big sealed-looking power plant has you expecting serene delivery, but while the power band is very even and predictable, the ever increasing buzz says: yes you are sitting over 4 flying pistons. It begs to be ridden hard. I like it more every day :)



DSC06520 by unoh7, on Flickr


Rear Spline lube (how are the splines?) and tranny oil change next on my list. I did drop some seafoam in the tank and crankcase a week ago. Oil is getting cloudy fast after that, which is good. I will swap it and the filter again in not to long.


Cold starts: I tried a bunch of methods, but now I just get her firing without touching the throttle (that can take 5 short attempts in the cold), then I push up the "choke". Warm, starts are instant.


Scariest thing is getting on and off. So crazy top heavy compared to all my other bikes. Stepping off without side stand down does focus the mind. Once she got away from me and the poor left bag had to catch her. LOL. Then I got to see what it takes to raise the dragon. ;)







  • Idaho
  • 1986 K100

Offline uhoh7

  • Motobrick Curious
  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #19 on: October 01, 2017, 12:22:37 PM »
Fuel Pump.


I have a very loud one. Too loud, long term.


What are my options?


TY so much guys :)


EDIT:



Go by unoh7, on Flickr


This came with the bike :)


I wish my fuel was lower, I should do the filter and lines etc. asap


I'll need special lines, no swell, source?


How should I treat those electrical connections? Special grease?


TY sirs


also: I can put the gas cap on facing correct direction.



L1059554 by unoh7, on Flickr


I hope this means the screws are not seized. Where do you guys go for new bolts and screws?
  • Idaho
  • 1986 K100

Offline billday

  • ^ SuperNatural Motobricker
  • Posts: 951
Re: 1985 K100 RS: practical rejuvenation
« Reply #20 on: October 01, 2017, 03:37:29 PM »
For parts and refurb kits, your new friends at Beemer Boneyard and Euro Moto Electrics are waiting to hear from you. Beemer Boneyard gives you 10% off if you type "BMWMOA" in the discount code field. Also check out MaxBMW's online parts fiche.

If you're replacing the fuel pump, look also at the holder and the fuel lines. Also study up on the Motobrick thread about alternative replacement fuel pumps.

  • New York State, USA 10977
  • 1985 K100

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 3566
Re: 1985 K100 RS: practical rejuvenation
« Reply #21 on: October 01, 2017, 06:27:13 PM »
For alternative pumps see here, some are a direct swap some require additional packing. http://www.motobrick.com/index.php/topic,5019.msg31050.html#msg31050
I've now got 1500 k's on my Chinese copy, extremely quiet and so far so good, but if you go Chinese be careful, the quality varies heaps and there are dodgy ones out there. I did a lot of research and went with a manufacturer, and I carry my old one as a spare.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline uhoh7

  • Motobrick Curious
  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #22 on: October 01, 2017, 07:16:10 PM »
Thanks guys,
I saw there is good looking kit on eBay for only 13 bucks, but
the pump I show, I actually have. The non-riders from whom I acquired the bike told me it was a oil pump, and I had not taken a close look. So I have a new pump.


I ordered a in tank fuel line kit and and new filter. Hopefully I burn a couple gallons before they arrive.


More on the Buzz (which u guys must know all about):


This is an early one, and as I noted it has it. I saw the various ways the buzz can be addressed, which I may try, but it's still novel, so I'm trying to "get it" before I do anything.


I was testing today at 4k or so. Amazing how much vibration changes with throttle. Most under decell. Steady speed almost as bad. Least with a smooth acceleration. At 7 or 8K I'm not thinking about it LOL. Bike is pretty smooth under hard acceralation, 0-70 buzz not really even apparent. But let off.......BUZZZZZZZ.


Not at all any deal breaker, but it's interesting. :)
  • Idaho
  • 1986 K100

Offline billday

  • ^ SuperNatural Motobricker
  • Posts: 951
Re: 1985 K100 RS: practical rejuvenation
« Reply #23 on: October 02, 2017, 08:05:46 AM »
Hey you really have to get that fuel filler turned around.

The steel screws do tend to fuse with the aluminum tank over time. Find a screwdriver that _exactly_ fits the screws. Bear down hard when you try to turn them. If they won't budge, try a smart rap on the screwdriver with a mallet. Another trick is to give it some clockwise energy, then try turning counterclockwise. Be firm but patient and they will budge eventually.

MaxBMW sells a nice refurb kit for the fuel filler, look up the "Gasket Set" on this page:

http://www.maxbmwmotorcycles.com/fiche/DiagramsMain.aspx?vid=51752&rnd=07242017
  • New York State, USA 10977
  • 1985 K100

Offline uhoh7

  • Motobrick Curious
  • Posts: 16
Re: 1985 K100 RS: practical rejuvenation
« Reply #24 on: October 08, 2017, 01:51:57 AM »
TY for the info.


My motive on the fuel pump has been a loud buzz coming from the tank. I stumbled on this post:
http://www.k100-forum.com/t11425-a-mod-for-early-petrol-tanks


I think my noise may be the same, as my bike is 85 with early tank. So before I swap the fuel pump, which may be fine, I thought I would address the return line fitting.


EDIT: I pulled my cap for inspection. Pretty clean in the tank. Most noise coming from fuel pump. The soft material around the pump does seem to have degraded, and fuel sort of rises around the pump body itself--I had just a bit left in the tank. I put the cap back on the right way, noting the drain which others have mentioned.


I think I will wait for winter and do the pump then :)
  • Idaho
  • 1986 K100

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