Author Topic: 1985 K100RS Renovation  (Read 4787 times)

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #75 on: December 12, 2017, 12:22:53 PM »
In case somebody doesn't know what the altitude plug looks like, here is an extract composed by frankenduck from the Repair Guidance section here.

*snip*


This is what mine looked like:

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

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 4405
Re: 1985 K100RS Renovation
« Reply #76 on: December 12, 2017, 12:25:53 PM »
This is what mine looked like: . . .
Somebody disrobed it. :mbird

It looks like this when it hasn't been stripped and flogged.

 
  • Along the Ridley in Vermont.
  • 1995 K75T 60,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #77 on: December 12, 2017, 12:33:11 PM »
Somebody disrobed it. :mbird


Lol


It was almost permanently installed too...I had to cut the cover off to get to it. It was glued on somehow. Very strange. The fellow I bought it from lives in Asheville, which is a shade over 2,000'. It would be hard to never dip below 4k' out here. I wonder if he realized he was running around running lean all the time...
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline The Mighty Gryphon

  • ^ Quintessential Motobricker
  • Posts: 3066
  • dyke chik wit attatood
Re: 1985 K100RS Renovation
« Reply #78 on: December 12, 2017, 01:43:15 PM »
I'll bet he was loving the gas mileage!
  • In my garage in Marilla, NY
  • '94 K75RT Mystic Red, '92K100RS White, '94 K75S Dakar Yellow
"Dohn f wit me, honkey, cuz I dindu nuffin'"

Current:
'94 K75RT "Ilsa, She Wolf of the SS"
'94 K75S "Cheetos"
'92 K100RS "Moby Brick"

Past:
'82 Honda FT500, '80 Honda XR185, '78 Honda XL125, '76 Honda XL125, '74 Honda XL125, '71 Ossa Pioneer, '68 Kawasaki 175

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #79 on: December 14, 2017, 11:17:55 AM »
I got my wheels back from powdercoat yesterday, along with the center and side stands. I took last night to install the bearings and rotors, and do some instrument cluster surgery.



Used the kerosene heater to warm the wheel, while I dropped the bearings in the deep freezer



A quick rap with the old bearing race drove it home.



The display for my gear indicator had never worked, but luckily, there is a guy in town who built a cafe bike out of his '85 K100RS and still had the cluster. I swapped the tach from his cluster to mine (discovering along the way that the cases changed, so I had to modify things a little bit), and I now have a working gear indicator.

My current frustration is that my 7L low fuel lamp does not work. Right now, the tank is bone dry. I get 683 ohms of resistance between both the 7L and 4L pins and the +12V pins on the bottom of the tank. Pins 7 and 8 on the green connector for the instrument cluster both show power with the key on. However, only the red 4L bulb will illuminate.

I have power on both sides of the 7L lamp, which leads me to believe that the circuit that turns that light on is not dropping to ground. I haven't decided how much time I'm going to waste chasing that down before I decide to just live with only the 4L warning light.

To add insult to injury, I accidentally caught the side of my starter button last night and broke it. So now I get to find that unobtanium part.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 2977
Re: 1985 K100RS Renovation
« Reply #80 on: December 14, 2017, 03:27:56 PM »
I have wracked my brain on the starter button. I believe someone in Spain is making them, and I think someone else has 3D printed them.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s, Lefaux, Vespa V twin

Online alabrew

  • Motobrick Curious
  • Posts: 31
Re: 1985 K100RS Renovation
« Reply #81 on: December 14, 2017, 03:48:25 PM »
I wouldn't worry too much about the 7L light not working. Very common to have it disconnected since you really don't need to know you are low on fuel that far to empty. I think they had not made a bike w/o a petcock before and wanted a little more insurance that you knew you were getting low on fuel
  • Alabama
  • 1985 K100, 1991 K100RS
Also:
2005 K1200LT
1979 R65
200,000 miles on BMW motorcycles

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #82 on: December 14, 2017, 05:52:23 PM »
I wouldn't worry too much about the 7L light not working. Very common to have it disconnected since you really don't need to know you are low on fuel that far to empty. I think they had not made a bike w/o a petcock before and wanted a little more insurance that you knew you were getting low on fuel


Yeah, I know they replaced the 7L light with the ABS light later on...I'm just kinda anal.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 4405
Re: 1985 K100RS Renovation
« Reply #83 on: December 14, 2017, 06:47:41 PM »
...I'm just kinda anal.
TMI!

Anyway, back to the starter button. ˇOlé!
  • Along the Ridley in Vermont.
  • 1995 K75T 60,000 miles
I wept because I had no radials until I met a man who had no splines.

Offline billday

  • ^ Quintessential Motobricker
  • Posts: 849
Re: 1985 K100RS Renovation
« Reply #84 on: December 14, 2017, 09:41:22 PM »
Euromotoelectrics sells the right hand control (includes starter button, turn signal etc.) for not a bad price.
  • New York State, USA 10977
  • 1985 K100

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #85 on: December 15, 2017, 01:13:48 PM »
Euromotoelectrics sells the right hand control (includes starter button, turn signal etc.) for not a bad price.


Yeah, eventually I'll drop the $300 for new left and right controls, but for now, what I have will work.


I did come up with a temporary solution to my starter button problem last night...


Started with a hunk of walnut and began whittling away...




Got it about where I wanted it



Carefully drilled the bottom



Pressed the contact post in with a dab of wood glue and...



I made a backup out of an old screwdriver handle





Should work fine until my replacement from hardtoptire arrives.



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

Offline rbm

  • ^ Quintessential Motobricker
  • Posts: 1494
Re: 1985 K100RS Renovation
« Reply #86 on: December 15, 2017, 09:25:52 PM »
My current frustration is that my 7L low fuel lamp does not work. Right now, the tank is bone dry. I get 683 ohms of resistance between both the 7L and 4L pins and the +12V pins on the bottom of the tank. Pins 7 and 8 on the green connector for the instrument cluster both show power with the key on. However, only the red 4L bulb will illuminate.

I have power on both sides of the 7L lamp, which leads me to believe that the circuit that turns that light on is not dropping to ground. I haven't decided how much time I'm going to waste chasing that down before I decide to just live with only the 4L warning light.
I reverse engineered some OEM circuits and posted the schematics, including the schematic for the low fuel indicator.  Luckily, the 4L comparator circuitry is the same as the 7L comparator circuitry so, if you have electronics skills, you can compare measurements in the 4L circuit to the same points on the 7L circuit to find the failing component.

When you disconnect the low fuel sensor from the harness, can you measure the resistance of each of the NCT resistors?  They should be the same and around 600 Ohms at 25 degrees C.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/
2011 Moto Guzzi V7 Racer

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #87 on: December 18, 2017, 10:32:31 AM »
I reverse engineered some OEM circuits and posted the schematics, including the schematic for the low fuel indicator.  Luckily, the 4L comparator circuitry is the same as the 7L comparator circuitry so, if you have electronics skills, you can compare measurements in the 4L circuit to the same points on the 7L circuit to find the failing component.

When you disconnect the low fuel sensor from the harness, can you measure the resistance of each of the NCT resistors?  They should be the same and around 600 Ohms at 25 degrees C.


Yeah, both sensors are good. I've got the cluster pulled out now to troubleshoot an inoperable speedometer today. I *think* the sensor is bad. It didn't respond to the soldering iron test, and it's extremely corroded. It gives a fluctuating resistance when tested...I'm going to try to get the Karamba utility installed today, and bench test the speedo.


Also, hey, it runs!


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

Offline rbm

  • ^ Quintessential Motobricker
  • Posts: 1494
Re: 1985 K100RS Renovation
« Reply #88 on: December 18, 2017, 12:38:58 PM »
Two tests to perform before you go down the route of assuming the rear sender is bad.  First, before you start, remove the sender from the final drive and wash it clean, then replace it back into the final drive.  The sender can collect metal particles from the final drive oil which will interrupt its operation.

To get a good connection, first clean the electrical connections on the harness with Deoxit or similar contact cleaner.  Make a couple of jumpers from some solid 18GA wire and insert those jumpers into the cable terminals.  Then clamp your meter leads to the jumpers using alligator clips.  Don't depend on you applying enough finger pressure on both test leads to get a reliable connection.  Can't be done and besides, you'll start measuring the electrical characteristics of your skin and not the sender.

(1) Measure the resistance across the Yellow and Brown wire right at the connector (under the right hand battery cover). You should measure 280 Ohms.


(2) if that succeeds, set your multimeter to AC milliVolts and set the range to about 100 mV.  While spinning the rear wheel at hand speed or engaging the drive in 2st gear while the engine idles, measure the output from the sender.  It should fluctuate around 30-50 milliVolts AC RMS.


If these tests succeed, your sender is in good working order.




P.S. I doubt it's the sender gone bad.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/
2011 Moto Guzzi V7 Racer

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #89 on: December 18, 2017, 01:31:34 PM »
Two tests to perform before you go down the route of assuming the rear sender is bad.  First, before you start, remove the sender from the final drive and wash it clean, then replace it back into the final drive.  The sender can collect metal particles from the final drive oil which will interrupt its operation.

To get a good connection, first clean the electrical connections on the harness with Deoxit or similar contact cleaner.  Make a couple of jumpers from some solid 18GA wire and insert those jumpers into the cable terminals.  Then clamp your meter leads to the jumpers using alligator clips.  Don't depend on you applying enough finger pressure on both test leads to get a reliable connection.  Can't be done and besides, you'll start measuring the electrical characteristics of your skin and not the sender.

(1) Measure the resistance across the Yellow and Brown wire right at the connector (under the right hand battery cover). You should measure 280 Ohms.


(2) if that succeeds, set your multimeter to AC milliVolts and set the range to about 100 mV.  While spinning the rear wheel at hand speed or engaging the drive in 2st gear while the engine idles, measure the output from the sender.  It should fluctuate around 30-50 milliVolts AC RMS.


If these tests succeed, your sender is in good working order.




P.S. I doubt it's the sender gone bad.


So I noticed weird resistance behavior last night with an old Fluke at the house. Figured I'd bring it into work and confirm it with a known good calibrated meter.


When I first touch the leads to the sensor wires, I get a reading of about 250 Megaohms. Over a period of about a minute, this reading will drop to as low as 100 megaohms, but never gets out of that range. Sometimes, if I move the sensor, the circuit goes open.


I think I've found the problem.

I'm still a noob on electronics though...learning as I go. Basic wiring is no problem, but troubleshooting components is still a learning experience.

Follow-up question, quoted from K100-forum:
Quote
Hi all, just getting ready to test my inop K100 speedo with Karamba, and wanted a little clarification...

This thread: http://www.k100-forum.com/t2038-karamba-speedometer-calibration-program-tutorial

Says you should connect power to pin 6, speedo signal to pin 22, and ground to 23.

Now, I'm a little confused here...power is 12v from a benchtop transformer to pin 6. That's easy enough.

Signal to pin 22...is this the tip/ring of the special cable? (yellow wire in image)

Ground to pin 23...surely this goes to the ground of my benchtop transformer, yes? Where should I connect the ground pin of the audio plug? Also to pin 23? (black wire in image)


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

Offline rbm

  • ^ Quintessential Motobricker
  • Posts: 1494
Re: 1985 K100RS Renovation
« Reply #90 on: December 18, 2017, 01:46:05 PM »
The text you referenced is in connection with bench testing the cluster while it is removed from the bike.  If you are planning on testing the cluster while it is installed on the bike, then all you need concentrate on is the sender connections to Pins 22 & 23;  the battery will be supplying the correct power to the cluster to power it on.


Irrespective of whether you will bench test the cluster or test it in-situ on the bike, then Pin 22 & 23 are from the sender, Yellow and Brown respectively.  The sender is not referenced to frame ground inside the instrument cluster, thus you need to connect both pins to the PC.  in the picture you referenced, the Yellow wire would go to Pin 22 and the Black wire to Pin 23, and the phono plug would go to the headphone output on the PC.


Assuming that you are bench testing the cluster, to supply power to the cluster from a DC power supply on the bench, hook up +ve to Pin 6 and -ve to Pin 13.  That tidbit is missing from the description.  Unfortunately the thread is locked so I can't go in to correct the text.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/
2011 Moto Guzzi V7 Racer

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #91 on: December 18, 2017, 02:01:25 PM »
The text you referenced is in connection with bench testing the cluster while it is removed from the bike.  If you are planning on testing the cluster while it is installed on the bike, then all you need concentrate on is the sender connections to Pins 22 & 23;  the battery will be supplying the correct power to the cluster to power it on.


Irrespective of whether you will bench test the cluster or test is in-situ on the bike, then Pin 22 & 23 are from the sender, Yellow and Brown respectively.  The sender is not reference to frame ground inside the instrument cluster, thus you need to connect both pins to the PC.  in the picture you referenced, the Yellow wire would go to Pin 22 and the Black wire to Pin 23, and the phono plug would go to the headphone output on the PC.


Assuming that you are bench testing the cluster, to supply power to the cluster from a DC power supply on the bench, hook up +ve to Pin 6 and -ve to Pin 13.  That tidbit is missing from the description.  Unfortunately the thread is locked so I can't go in to correct the text.


Thanks, that's exactly what I was after. I'll be bench testing it shortly then.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #92 on: December 18, 2017, 02:30:47 PM »
The speedometer works perfectly with the Karamba utility, however the odometer and trip meter do not. Guess that's next on the list.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline Martin

  • ^ Quintessential Motobricker
  • Posts: 2977
Re: 1985 K100RS Renovation
« Reply #93 on: December 18, 2017, 02:37:01 PM »
Gears turn into cheese. On replacing them I was told not to lubricate them as greasing speeds up the process.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s, Lefaux, Vespa V twin

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #94 on: December 19, 2017, 12:05:36 PM »
Gears turn into cheese. On replacing them I was told not to lubricate them as greasing speeds up the process.
Regards Martin.


Yeah, I noticed the green and orange gears are toast too. I'll probably live without the odometer for awhile.


I got a lot of piddly stuff accomplished last night, and finally got it off the stands/box. If everything goes to plan, I'll be able to take it on a first ride tonight.


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

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #95 on: December 19, 2017, 02:05:10 PM »
Side note...I let the bike idle for 15 minutes or so to get up to temp and check proper operation of the fan. Imagine my surprise when I heard a hissing and popping from the fuel tank, only to discover my fuel boiling!

After looking around a bit, boiling fuel seems to just be a Kwirk and nothing to worry about. Still a bit surprising and disconcerting if you don't expect it though.


A follow-up question...I hear pressure hissing out around my fuel cap, and when I release it, there is a "woosh" of pressure. Is there some pressure relief somewhere that's not functioning or is this just normal behavior?

The fan cycles as it should...comes on around 215*, goes off around 190*. I think I'll be fitting an aux switch for the fan before summertime hits.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Online alabrew

  • Motobrick Curious
  • Posts: 31
Re: 1985 K100RS Renovation
« Reply #96 on: December 19, 2017, 03:57:52 PM »
There is a vent for the tank. On my early '85, it exits, along with the fuel cap drain line, under the tank on the right rear into a drain cup fashioned to the frame.
  • Alabama
  • 1985 K100, 1991 K100RS
Also:
2005 K1200LT
1979 R65
200,000 miles on BMW motorcycles

Offline propav8r

  • ^ Motobrick Curious
  • Posts: 95
Re: 1985 K100RS Renovation
« Reply #97 on: December 19, 2017, 04:01:24 PM »
There is a vent for the tank. On my early '85, it exits, along with the fuel cap drain line, under the tank on the right rear into a drain cup fashioned to the frame.


Hmm. I'll have to check. I did ensure the water drain line was clear, but didn't know about the vent. Thanks.
  • Franklin, NC
  • 1985 K100RS, 1978 GL1000, 1972 Kawasaki H2 750

Offline billday

  • ^ Quintessential Motobricker
  • Posts: 849
Re: 1985 K100RS Renovation
« Reply #98 on: December 19, 2017, 05:04:35 PM »
Make sure your fuel filler is oriented correctly. The hinge should be toward the back of the bike. If it's the other way around it blocks the vent.

What looks like fuel boiling can be just the splashing of fuel returning to the tank.

Your FYK (Finest Year K) looks great, keep those pictures coming.
  • New York State, USA 10977
  • 1985 K100

Offline Laitch

  • ^ Quintessential Motobricker
  • Posts: 4405
Re: 1985 K100RS Renovation
« Reply #99 on: December 19, 2017, 05:26:42 PM »
A follow-up question...I hear pressure hissing out around my fuel cap, and when I release it, there is a "woosh" of pressure. Is there some pressure relief somewhere that's not functioning or is this just normal behavior?
My guess is that you don't have much fuel in the tank. I hear the whoosh when I open the cap for a low tank fill up.
  • Along the Ridley in Vermont.
  • 1995 K75T 60,000 miles
I wept because I had no radials until I met a man who had no splines.