Author Topic: 1985 K100RS Renovation  (Read 24557 times)

Offline propav8r

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1985 K100RS Renovation
« on: July 31, 2017, 04:28:27 PM »
Hey all, after several weeks of trolling Craigslist and motorcycle classifieds, I just purchased my second motorcycle and first BMW, a 1985 K100RS.


I saw it listed on Craigslist and started trying to get ahold of the guy early last week. Finally, he returned my email and I arranged to meet him this past Friday.


The ad said that the bike had been dropped and had a photo of the right side. The lower fairing is all busted, but the upper fairing is only scraped and is salvageable/repairable. The mirror is mismatched, but hey, at least it's there.


The long and short of it was that the owner had traded a friend a truck for this bike about 5 years ago, not long after the accident. The bike had always had electrical issues, and he had been unable to get it running. In addition, he reported that the brakes were inop, and he had to drag the clutch while pushing it around to stop.


"Well, at least the clutch works." I thought to myself.


I asked him to put the battery on the charger before I got there so I could at least hear it crank over. When I got there, he hadn't done that, which was okay with me...I just used it as a bargaining chip.


A quick once-over didn't reveal any obvious issues I was unprepared for. The included hard bags and trunk (not pictured) were a welcome addition.


His asking price was $800. I had convinced myself that I wasn't going to may more than $650 on the way over there, so that's all the cash I took with me.


After about 5 minutes of poking and prodding, I told him I didn't want to offend, but with the body damage, brakes, and questionable state of the motor, I was only prepared to offer $350. He himmed and hawed a bit, counteroffered $450, and we met in the middle at $400. It even came with a couple uncut folding keys and a Clymer manual, both nice touches.


I figured that even if the motor turned out to be junk, the titled frame and a number of decent parts would be enough to make my money back.


I loaded the bike up in the trailer, strapped it down, and headed home.





When I got home and unloaded it, I popped the trans into 5th gear and pushed the bike around a bit...cool, the motor isn't locked up.


I pulled it in the shop and pulled the fairings and bodywork off while gritting my teeth and preparing for the worst wiring hackjob possible and...nothing. Everything, save for a heated vest connection off the front light, was OEM and uncut. Hmm.


Hooked up the battery charger and flipped the key on...the dash lit up and no magic smoke escaped. After letting the charger sit for a bit, I hit the start button and was greeted by a buzz from the starter relay. I popped the cover off that and hit the button again and saw it arcing between the relay contacts. When I pushed the relay closed manually, I would sometimes get a little bit of a revolution from starter.


I pulled the battery off the bike and let it charge overnight. In the morning, it was only holding 6v. Well that's no good. Even with the charger hooked up, there just weren't enough amps to turn the motor over.


I grabbed a new battery since I was going to need one anyway and hooked it up. There were some dead bugs and such in the fuel tank (it had been stored dry), so I blew those out, hooked up the tank, threw some gas in it, and...



So that's where we're at...Front master cylinder needs a rebuild or replacement. Still undecided on which I'll do. I need to track down those couple panels, but overall, it's a pretty great starting point for a nice bike.

I'll keep y'all appraised of progress and probably flood the thread with questions and advice requests too.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #1 on: July 31, 2017, 04:31:37 PM »
A couple quick photos here that I forgot to add to the OP:





  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline psykologik

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Re: 1985 K100RS Renovation
« Reply #2 on: July 31, 2017, 05:20:08 PM »
 Nice score! I love my RT, but if I could find a little RS fixer-upper like this, I'd snap it up in a heartbeat. Have fun...


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Offline The Mighty Gryphon

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Re: 1985 K100RS Renovation
« Reply #3 on: July 31, 2017, 05:31:37 PM »
Sweet!  Hope the guy who sold it doesn't see this thread!  I know it would ruin my day.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue, '89 K100RS Special edition White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too
'89 K100RS SE

Offline MIbrick

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Re: 1985 K100RS Renovation
« Reply #4 on: July 31, 2017, 05:36:27 PM »
Nice looking RS. Watched your YT vid; yours sounds just like mine. :)  I wonder if the light blue rides any cooler than schwarz. Nice grab!
  • Michigan
  • 1986 K100RS (ohne Tragkorb)

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #5 on: July 31, 2017, 05:39:02 PM »
Nice looking RS. Watched your YT vid; yours sounds just like mine. :)  I wonder if the light blue rides any cooler than schwarz. Nice grab!


Someone on FB pointed out the Luftmeister exhaust which is a nice touch. It does have a hole in it (crash damage? rust? dunno yet) that you can hear ticking.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline Martin

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Re: 1985 K100RS Renovation
« Reply #6 on: July 31, 2017, 05:39:34 PM »

Welcome through the portals to K-Pox madness. they are highly addictive. Bricks do not like inactivity and benefit from going over all the electrical connectors. Go buy a can of Deoxit the Brick riders best friend, clean all connectors. Optional is to smear dielectric or heavy silicone grease lichtly around the connectors. Some inmates believe this can cause conductivity problems, I believe it keeps out air and moisture which leads to corrosion and problems. Check to see if your fuel pump is going when you hit the starter button, there is a 4 pin connector under the RH side of the tank that can cause problems. Failure to have a fully charged battery can caused the starter relay contacts to weld close. If this happens sometimes the stater will keep on going, overheating the battery. A battery isolator switch can be installed to overcome this if and when it happens.  Rubber parts deteriorate especially the ones in the tank replace all the hoses in the tank with submersible graded hose. Replace the fuel filter. Replace all other fluids and filters.
Good luck regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Christopherguzzi

  • My first Beemer🏍.
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  • Posts: 129
  • It ran when it was parked........27 years ago😳.
Re: 1985 K100RS Renovation
« Reply #7 on: July 31, 2017, 06:52:42 PM »
Nice find!  You did good to bargain for as low a price as you did.  Will allow for whatever parts and work you'll need to do in order to get the bike in tip top shape.  Have fun!
  • Little Canada, Minnesota
  • 1986 K75C
Christopherguzzi

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #8 on: August 01, 2017, 12:00:12 PM »
Could anyone tell me what color this bike is? It looks a bit like Tundra Green 412, but I'm not positive.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #9 on: August 01, 2017, 03:51:43 PM »
Just ordered a master cylinder rebuild kit...hopefully that'll be here by the end of the week. I'm going to try and straighten the bent brake lever in my vise without cracking it.

I'll pull the rear brakes apart tonight and figure out why they're not working. With any luck, it'll be rideable by the weekend.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #10 on: August 01, 2017, 03:53:07 PM »
Sorry for the multiple posts...trying to get to that "edit" button (seems silly that's locked out for newbies...)

Kicking around the idea of a repaint since whatever panels I wind up with won't match my current color. I'd love to do a brilliant white or pearl white. Still undecided. Can I get the "Motorsport" decal kits anywhere?
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline Filmcamera

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Re: 1985 K100RS Renovation
« Reply #11 on: August 01, 2017, 04:35:18 PM »
With any luck there is a colour code under the seat.  Also there is a list of what the codes are here

http://www.bmbikes.co.uk/paintcodes/greens.htm

  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2018 Triumph Street Triple RS 765
Poserbricker

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #12 on: August 01, 2017, 04:48:48 PM »
With any luck there is a colour code under the seat.  Also there is a list of what the codes are here

http://www.bmbikes.co.uk/paintcodes/greens.htm


Gotcha, thanks!
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline The Mighty Gryphon

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Re: 1985 K100RS Renovation
« Reply #13 on: August 01, 2017, 06:23:44 PM »
The color codes are a bitch to find places that can mix them here in the States.  The BMW paints are made by BASF, and nobody has the formulas in their data bases.  Best way to match is to take a panel to an automotive paint supplier and have them match it with their computer.  I was able to get a perfect match for Mystic Red that way.  I would guess the part of the rear cowl that is under the seat will give the best rendition of the unfaded color.
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '91K100RS White/Blue, '89 K100RS Special edition White/Blue
Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'91 K100RS "Moby Brick Too
'89 K100RS SE

Offline rbm

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Re: 1985 K100RS Renovation
« Reply #14 on: August 01, 2017, 07:33:15 PM »
Can I get the "Motorsport" decal kits anywhere?
Heritage Stickers at http://www.heritagestickers.eu/cat/
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #15 on: August 01, 2017, 10:13:44 PM »
I spent some time this evening messing with the rear brakes. There was some water in there, but once I got that flushed out, it's back to working again.



Found the source of my exhaust leak too... I'll pull that off tomorrow and get started on the patching.


  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline F14CRAZY

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Re: 1985 K100RS Renovation
« Reply #16 on: August 01, 2017, 10:59:44 PM »
That's the problem with aftermarket K exhausts...they ain't stainless like the OEM ones
  • Grand Rapids, MI
  • '87 K75C
'87 K75C w/ Pichler V1 fairing. LED's, CATZ driving lights, Audiovox cruise, LT top case, tons of other mods by Drake...


Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #17 on: August 03, 2017, 11:56:51 AM »
I have sourced my needed fairing and panel, plus spares for the other side. The front master rebuild kit should be in today. Depending on the needs of the wee babe this evening, I might be able to squeeze in a ride tonight or tomorrow.

I now have a set of spare fairings...guess I'll repaint the two I don't need and save them for a potential left side drop.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #18 on: August 04, 2017, 09:51:11 AM »
Got the master cylinder rebuild and the front brakes returned to operation last night. It was too late to ride without a headlight, but I should be able to get it around the block tonight.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #19 on: August 07, 2017, 10:12:38 AM »
Well, it runs good enough that I was able to ride it around the block.



Pulled the exhaust off last night...the header will need some weld repairs, but nothing too crazy.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline mufflerbearing

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Re: 1985 K100RS Renovation
« Reply #20 on: August 07, 2017, 04:10:26 PM »
Nice work propav8r!
Good advice from everyone so far.
I like you got into my first K about 2 years ago and am really liking it (K100 RT)
Had to inspect/fix many components as you have done.  Clymer Manual is invaluable.  Many good how-to's on YouTube, particularly the Chris Harris ones.  Keep up the good work!

  • Holly Springs NC
  • 1985 K100RT

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #21 on: August 07, 2017, 05:08:12 PM »
Nice work propav8r!
Good advice from everyone so far.
I like you got into my first K about 2 years ago and am really liking it (K100 RT)
Had to inspect/fix many components as you have done.  Clymer Manual is invaluable.  Many good how-to's on YouTube, particularly the Chris Harris ones.  Keep up the good work!


Yep, this one came with a Clymer, so that's been a big help. A few bits from Max BMW are waiting for me at the house now. I guess the next step is to order tires and change the fluids. I should probably do a spline lube too. The bike has 37K on it and sat for a long time, so even if it was done at 20k, the service interval is coming up soon, and grease tends to dry out after sitting for a long while. Apart from the $45 (gag) clutch rod boot, there don't seem to be any other parts that need to be replaced while everything is apart except for the clutch if it's worn.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #22 on: August 08, 2017, 10:15:09 AM »
Spent last night trying to get my ignition switch working right. It had been rekeyed at some point and couldn't turn all the way to the "run" position. A few minutes with some files on the wafers let everything rotate like it should again.

I then realized that the actual switch is so biodegraded that the tab for the set screw is missing. That means the switch can't stay in the housing, and the switch and rear cap just fall out.

This is what mine looks like:



And what it should look like:



I guess I need another switch. Kinda chaps me to pay $80 for a new one. If anyone has a decent used one, let me know. I also might try to adapt a '68-'72 VW ignition switch. The attachment looks the same, but I think the actuator starts and ends at a different angle relative to the locating pins.



I'll figure something out, and probably spend $100 to save $20 along the way.

I also got my exhaust disassembled after much cussing and bashing. I could hear something rattling around inside...turns out the packing had disintegrated/vanished after all this time.







I'm taking the exhaust for sandblasting today. I want to make sure there arent' any more rust holes about to poke through that I can head off at the pass.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline alabrew

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Re: 1985 K100RS Renovation
« Reply #23 on: August 08, 2017, 07:09:04 PM »
Kind of getto, but I broke my switch while repacking the steering head bearings. Rather than buy the part, wait the weeks it would take to get, and run down the wires, I just wired in a flip switch, kind of hidden under the steering pad. No key needed.
  • Alabama
  • 1985 K100, 1991 K100RS
Also:
2005 K1200LT
1979 R65
200,000 miles on BMW motorcycles

Offline propav8r

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Re: 1985 K100RS Renovation
« Reply #24 on: August 09, 2017, 09:50:24 AM »
Kind of getto, but I broke my switch while repacking the steering head bearings. Rather than buy the part, wait the weeks it would take to get, and run down the wires, I just wired in a flip switch, kind of hidden under the steering pad. No key needed.


Yeah, given that this switch works, I think I'm just going to hold it in the housing with a little dab of adhesive to get me on the road. The $80 can be spent somewhere else for the time being.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

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