Author Topic: Just bought a 1987 K75s and value your expertise  (Read 408 times)

Offline EspressoForyoU

  • Curious
  • Posts: 5
Just bought a 1987 K75s and value your expertise
« on: October 29, 2018, 11:57:12 PM »
I just bought a 1987 k75s and I am sure I will be searching the forum for information.  The bike runs and looks pretty good.  It has be repainted at some point. Showing 28,000 but odometer is not working. I will be doing some general maintenance on the bike and checking the final drive splines and changing fluids right away.  I would appreciate any suggestions on what I should look at before I start putting miles on the bike.  It starts, runs and stops except the rear brake is not working.

Thanks Randy in Memphis
  • Memphis
  • k75, g 650xcountry, f650gs, r100, 1972 Yamaha DT2

Offline blackie1

  • ^ Proficient Motobricker
  • Posts: 150
  • christchurch nz
Re: Just bought a 1987 K75s and value your expertise
« Reply #1 on: October 30, 2018, 02:24:11 AM »
  • new zealand , where else would u want to live, really
  • 1991 K75RT naked 40,000kms

Offline mlytle

  • ^ SuperNatural Motobricker
  • Posts: 891
Re: Just bought a 1987 K75s and value your expertise
« Reply #2 on: October 30, 2018, 09:05:22 AM »
Replace all the rubber hoses.  Fuel, brake, vacuum and coolant.  See the thread in my sig line.
  • alexandria, va
  • 92 K75s, 94 K75s, 96 K1100RS SE (custodian), 09 K1300s
Marshall
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline stokester

  • ^ Proficient Motobricker
  • Posts: 405
Re: Just bought a 1987 K75s and value your expertise
« Reply #3 on: October 30, 2018, 09:09:35 AM »
Welcome Randy.

Yes you will find information here on nearly everything you need to repair your brick.  Learn how to do a good site search and followup on solutions to add to the knowledge base.

As far as your odometer, it's a common problem, you may need to get some new gears from -> odometergears.com 
Jeff's got detailed instructions you may want to check out.
  • Yorktown, Virginia
  • '94 K75S - '93 K75S - '91 R100RT - '78 R100S

Offline The Mighty Gryphon

  • ^ Quintessential Motobricker
  • Posts: 3917
Re: Just bought a 1987 K75s and value your expertise
« Reply #4 on: October 30, 2018, 09:28:24 AM »
Welcome!  Read the article on what to do with a new brick.  Doing a thorough maintenance on the whole bike will reveal any additional work it may need. 

While the bike runs now, if it has sat idle for any length of time it may need some additional work to offset the effects of gummy, broken down fuel on the rubber bits in the tank and the injectors.  Remove the filler on the tank and have a good look around inside.  If it's clean and shiny you are probably in good shape as far as the rubber bits in there.  If not,  one of the first things you need to address is cleaning all that crap out and probably replacing the fuel pump vibration damper.  No matter what, replace all the fuel lines with the proper grade of ethanol resistant hose. 

Check for any bubbling paint on the low points of the tank.  That usually means corrosion that may cause fuel leaks. 

Get a can of DeOxit contact cleaner and go through the entire bike cleaning EVERY electrical connector and switch.  Be especially mindful of the four pin connector to the fuel tank.  That connector causes a lot of problems with fuel pump operation.  You might also want to clean the ignition switch which has also caused a lot of whack on these old bikes.
  • 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 natalena

  • ^ Motobrick Curious
  • Posts: 86
Re: Just bought a 1987 K75s and value your expertise
« Reply #5 on: October 30, 2018, 09:56:04 AM »
Welcome and congrats on the new brick. I can tell it's already getting special to you, as there's a cleared out area around the bike ;) This forum is like the Farmers Almanac of Bricks, whatever info you're looking for, it's probably here. Cheers
  • East of Joshua Tree
  • 1987 K75s #0919

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5724
Re: Just bought a 1987 K75s and value your expertise
« Reply #6 on: October 30, 2018, 01:20:26 PM »
Welcome, Randy. Thanks for the photos. Please learn how to post them in correct orientation.
  • 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.

Offline mlytle

  • ^ SuperNatural Motobricker
  • Posts: 891
Re: Just bought a 1987 K75s and value your expertise
« Reply #7 on: October 30, 2018, 04:55:49 PM »
Welcome, Randy. Thanks for the photos. Please learn how to post them in correct orientation.

i was thinking the bike traveled from down under in the first two, crossed equator in third and arrived in us with the last...:-)

and OP...check the date code on the tires.  more than 5 years old...toss them!
  • alexandria, va
  • 92 K75s, 94 K75s, 96 K1100RS SE (custodian), 09 K1300s
Marshall
Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Offline EspressoForyoU

  • Curious
  • Posts: 5
Re: Just bought a 1987 K75s and value your expertise
« Reply #8 on: October 30, 2018, 10:20:16 PM »
Thanks for the input everyone.  I don’t know why the images posted upside down.  Seems to be a common issue with the way many forums are built.  I tried to find a way to edit the post but I couldn’t figure it out.   I will get better. I rode the bike about 15 minutes today.  Bike ran fine in 1st and 2nd all the way to redline.  Seems like in 3rd and 4th the closer I get to red line that I detected a slight miss.  The PO said he replace the fuel pump, cleaned the tank, replace the fuel lines and injectors. I double check his work. 
  • Memphis
  • k75, g 650xcountry, f650gs, r100, 1972 Yamaha DT2

Offline The Mighty Gryphon

  • ^ Quintessential Motobricker
  • Posts: 3917
Re: Just bought a 1987 K75s and value your expertise
« Reply #9 on: October 30, 2018, 10:38:51 PM »
Have the valves been adjusted? 

Throttle bodies balanced? 

How is the Hall Effect Sensor plate at the front of the engine set? 

Has the bike sat for a year or so?  You might want to run a couple tanks of fresh fuel with Techron fuel system cleaner through the engine to clean out the injectors a bit more. 

Have the filter screens in the injectors been changed?

I have to admit that I almost never run at red line(more like 6000-6500) so I can't say if mine breaks up a bit at redline.  Never had to address a miss at redline.
  • 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 Laitch

  • ^ Quintessential Motobricker
  • Posts: 5724
Re: Just bought a 1987 K75s and value your expertise
« Reply #10 on: October 30, 2018, 10:56:26 PM »
Thanks for the input everyone.  I don’t know why the images posted upside down.  Seems to be a common issue with the way many forums are built.   
It's the way many forum users are built. When it happens, they can't be bothered to research why it happens. The information is out there though.

Run a newly-purchased used bike at redline after you've checked valve clearances and all the other items Gryph mentions—not before.
  • 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.

Offline Chaos

  • ^ Quintessential Motobricker
  • Posts: 2204
  • Mars needs women!
Re: Just bought a 1987 K75s and value your expertise
« Reply #11 on: October 30, 2018, 11:40:52 PM »
Nice looking survivor!  Newer style bags are nice, the dashboard and maybe the bars look like they might be from a K75C, pretty common conversion though I feel the original bars with risers work and look better.  Way back when I had my bike on a dynamometer it missed a bit at redline, you could see puffs of black come out the tailpipe as the carbon got cleaned out. After a minute or so it was flawless.  As others have said, get all the tune up bits in order before wailing on it too much.   
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
2012 Ural 2WD sidecar (BMW's bastard step child)

Offline caveman

  • ^ Motobrick Curious
  • Posts: 62
Re: Just bought a 1987 K75s and value your expertise
« Reply #12 on: October 31, 2018, 04:53:04 AM »
+1 on completing all the maintenance after that these bikes seem to have a self healing property.... the more you run them the better they run.
Good luck and enjoy!
  • Kennerdell, PA.
  • 87 K100RT, 88 K100LT

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 5724
Re: Just bought a 1987 K75s and value your expertise
« Reply #13 on: October 31, 2018, 07:08:45 PM »
Bike ran fine in 1st and 2nd all the way to redline.  Seems like in 3rd and 4th the closer I get to red line that I detected a slight miss. 
Stuttering and missing is a characteristic of the rev-limiter's effect on the engine at redline. It's to inhibit damage being done to the engine by those who don't pay attention to what's happening or choose to ignore it.
  • 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.

Offline billday

  • ^ SuperNatural Motobricker
  • Posts: 927
Re: Just bought a 1987 K75s and value your expertise
« Reply #14 on: October 31, 2018, 10:19:05 PM »
You're taking it to red line on public roads.  . . . with no rear brake?
  • New York State, USA 10977
  • 1985 K100

Offline Barry in IN

  • ^ Proficient Motobricker
  • Posts: 124
Re: Just bought a 1987 K75s and value your expertise
« Reply #15 on: November 08, 2018, 05:50:51 PM »
Nine days and nothing but crickets.  Maybe the front brakes gave up, too.   
  • Indiana
  • 1992 K75S Lili Von Shtuppe
A pox on cafe “builders”

Offline EspressoForyoU

  • Curious
  • Posts: 5
Re: Just bought a 1987 K75s and value your expertise
« Reply #16 on: November 08, 2018, 10:37:52 PM »
I am still alive, fortunately the front brakes work well enough.   Having a delay in getting the title from the seller.  Because of this I am not riding or doing anything to the bike until I get the title in hand.   I am researching a lot about the bike in the meantime. 
  • Memphis
  • k75, g 650xcountry, f650gs, r100, 1972 Yamaha DT2

Offline Barry in IN

  • ^ Proficient Motobricker
  • Posts: 124
Re: Just bought a 1987 K75s and value your expertise
« Reply #17 on: November 08, 2018, 10:52:43 PM »
Uh-oh.
  • Indiana
  • 1992 K75S Lili Von Shtuppe
A pox on cafe “builders”

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