Author Topic: '85 K100RT Build - "TT" Endurance Racer  (Read 11522 times)

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
'85 K100RT Build - "TT" Endurance Racer
« on: June 04, 2016, 12:25:05 PM »
Hello all!

This is the start of my K100 "TT" build thread on the Motobrick forum. :)

Austin has been the host to two great events for the past several years: MotoGP at Circuit of the Americas and the Handbuilt show. After going to this year's show, I felt inspired to build a bike. In the past I've dabbled with cafe-racering my old Street Triple and built a race bike out of my Daytona 675R. For this project I wanted to start with something older, simpler, and less expensive. A bike that I could tear down, put back together, and modify to my hearts content. I thought about R-bikes and old Hondas, but they are getting harder to come by unmodified and/or for a reasonable price.

A little over a month ago, I found a 1985 K100RT with 77k miles for a very reasonable price to use a the basis of my build. This bike had obviously been dropped on the right side, was missing some fairing pieces, no radio, etc. -- perfect for my purposes. I handed over the cash, and rode it home in a light rain, fairings shaking all the way home. I believe I'm the 5th owner (the 4th bought it to fix and flip it).

  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #1 on: June 04, 2016, 12:44:00 PM »
Here's the progress on the tear down so far. At this point, everything is disconnected and ready for me to remove the frame. Before I do that, I'm going to test fit the fairings that are arriving today. :clap:
  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #2 on: June 04, 2016, 01:22:28 PM »
There have been a few small issues along the way.
  • The tank was missing its bracket - ordered a replacement from eBay
  • The oil pan looks like someone tried to pry out the filter with a screwdriver - ground the spots flat to 600 grit
  • Rear disc was thinner than .14" and was cracked. Rear pads completely worn down. - ordered a replacement rotor and pads from EBC
  • The drive splines were completely dry when checked. The female side looks completely ok, and the male side has a slight hook to it - moly'd both sides back up and reinstalled. Though I can't figure out how to torque those :nono bolts since the head of my wrench is too big. Likely I need hinged driver.

  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline The Dude

  • ^ SuperNatural Motobricker
  • Posts: 509
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #3 on: June 04, 2016, 04:26:53 PM »
"Rear disc was thinner than .14" and was cracked. Rear pads completely worn down."

Thanks for reminding me to have a good look at mine....
  • Auckland, New Zealand
  • K75s
Current.
TR6R 1973 from new.
Moto guzzi 850 III .1983 from,almost, new.
K75S 1986 from new.vin-0103141
On my second millionth km.give or take a hundred k Kay's.
"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there."
All the best!

Offline TimTyler

  • Adrninistrator
  • ^ Quintessential Motobricker
  • Posts: 1884
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #4 on: June 04, 2016, 06:32:15 PM »
Might as well take off the front master cylinder and brake lines, and reinstall with new lines when you put everything back together.

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #5 on: June 04, 2016, 06:49:38 PM »
Might as well take off the front master cylinder and brake lines, and reinstall with new lines when you put everything back together.

I'm planning on it. Hadn't gotten around to it quite yet. I'll definitely need new lines as I'm planning to have a fairing stay come up and out of the triple tree nut where the current brake line is. Weird that they routed it that way. Is that common on BMWs?
  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #6 on: June 07, 2016, 07:27:24 PM »
The frame is off. :)

  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #7 on: June 07, 2016, 07:29:22 PM »
And the fairings are in... :)

  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline jjs1234

  • ^ Proficient Motobricker
  • Posts: 409
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #8 on: June 07, 2016, 07:41:05 PM »
ooh! Mind if I ask where the front came from?
  • Northern California
  • 1984 K100
Check out my build! Complete tear-down!
Mr. Creative

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #9 on: June 07, 2016, 07:48:33 PM »
Fairings and headlight are from Airtech Streamlining - F1F (XR69) + MORI2 tail + some handcuffs.
  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline jjs1234

  • ^ Proficient Motobricker
  • Posts: 409
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #10 on: June 07, 2016, 07:59:22 PM »
So your planning to mod it? I didnt see a k100/1100 fairing on there. But it looks fierce!!
  • Northern California
  • 1984 K100
Check out my build! Complete tear-down!
Mr. Creative

Offline zroadhouse

  • Motobrick Curious
  • Posts: 12
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #11 on: June 07, 2016, 09:15:49 PM »
Yes. This is a mod build. I'll be making fairing brackets, stay, etc. I picked this fairing based on style and size.


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  • Austin, TX
  • 1985 K100RT
1985 K100RT

Offline Elipten

  • ^ SuperNatural Motobricker
  • Posts: 715
Re: '85 K100RT Build - "TT" Endurance Racer
« Reply #12 on: June 07, 2016, 10:55:05 PM »
Now this is looking interesting and has my attention.
  • San Antonio, TX
  • 1990 K75RT

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