Author Topic: Awakening 1987 K100RS from 10 year slumber.  (Read 8041 times)

Offline SpecialK

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #125 on: August 04, 2019, 06:20:21 PM »
With a 50:50 coolant mixture in hot weather like we've been having, the fan should activate intermittently in slow or stopped traffic. The overheat indicator should not light up. If you just let it idle in your driveway, the fan—if not seized—should turn on in 10–15 minutes or so. It will run briefly but intermittently until the moto is in motion.

First time I am testing the radiator, pump, thermostat, and fan after filling it with 50:50 Prestone coolant. I have not let the bike run more that a minute or two until now.
Started the bike and let it run on idle until the fan came on. It came on after about 20 minutes and the temp. gauge was around 3/4. The fan would stay on for about 40 seconds until the gauge went down between 1/2 and 3/4 and then it would shut off. Everything seems to be working correctly and no leaks anywhere, Now that it's warm I will change the oil.



Changed the oil. Looks like all the previous servicing was at BMW or the guy bought OEM parts. Filter was BMW. I went to Advance Auto and they cross referenced the filter and wrench, 76mm. Total was around $12. Has the same rubber washer as the OEM.

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  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline SpecialK

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  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #126 on: August 05, 2019, 06:37:05 PM »
Tested the bike around the block today. Shifted well and felt smooth but the speedometer is not working. I did a search and saw Frankenduck's solution to pull off the cluster, remove the 9 screws and pull the pin connector off then clean the pins, deoxit, and put back.
Hope that works.

 :bmwspinn

Forgot to mention; the rear brake is not working. There is fluid in the reservoir but the shoes aren't grabbing. Could be a frozen caliper? Open to suggestions.
Thanks.
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline SpecialK

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  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #127 on: August 06, 2019, 05:51:16 PM »
Hoping to get some answers here for some items that need attention.

-I need to remove the instrument cluster (K100RS). Speedo is not working. Do I need to remove the entire fairing or just the black panel behind the cluster, or the windscreen?
-The right mirror casing has some scratches and when I removed it, there was a white wire and plug, and another brown wire that was just hanging there with a bare end. The front signals are not working.
-Foot brake not working. Frozen caliper piston?

Thanks!

 :johnny I have to admit, I am very nervous about riding this bike. I got my motorcycle license about 40 years ago and had a CB360 and a Kawasaki SR650 for just a year or two so I didn't put a lot of street miles on and have not ridden much since except about 8 years ago when the bike bug got me and I restored a GPZ750 and then a R75/5. I only rode those around for a few miles and had to get used to the feel and weight. So I do not consider myself an experienced rider.
Now I have the K100RS that is 558lbs and seat height of 32" so I can't touch the ground flat footed and am having some trouble pushing the bike around when seated. This is not a machine to be taken lightly. I don't think it wise for me to go out on a "highway" and intend on staying on smaller local roads for now.
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline TommyT

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #128 on: August 06, 2019, 06:22:15 PM »
Forgot to mention; the rear brake is not working. There is fluid in the reservoir but the shoes aren't grabbing. Could be a frozen caliper? Open to suggestions.
Thanks.
I would bet it is frozen, after 10 years of no use and old brake fuild likes moisture, there is probably a little rust on the puck.
  • Olive NY
  • 1990 K75s, 1990 K75RT

Offline SpecialK

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #129 on: August 06, 2019, 06:26:29 PM »
I would bet it is frozen, after 10 years of no use and old brake fuild likes moisture, there is probably a little rust on the puck.

Thanks for the reply. Would you suggest bleeding the line then removing the caliper and try to get the puck to move?
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline TommyT

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #130 on: August 06, 2019, 07:32:15 PM »
Thanks for the reply. Would you suggest bleeding the line then removing the caliper and try to get the puck to move?
Well, I have not done this to a K bike, but I used to a long time ago buy old 911 Porsches that usually sat a long time. I would take the caliper off, lock down one side of the caliper with small clamp or large stainless hose clamp and apply a little air pressure into the caliper until the unlocked puck/piston would pop out. I would gently clean rust off the piston and the bore in the caliper. I would put in new seals and dust boots on before I would repeat this on the other piston. Be very careful with the air pressure, the first time I did it in over did it and the piston come out a lot faster then I wanted.

You could try taking the wheel and disk off the bike and put a thin screw driver in between the pads and use the brake lever to push the pads out some and then push them back all the way and then pump them back out with the screw driver in between the pads again.  If the pads do not move then go try the method above to do a full clean up of the brake pistons.
  • Olive NY
  • 1990 K75s, 1990 K75RT

Offline The Mighty Gryphon

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #131 on: August 06, 2019, 07:38:14 PM »
I would try to bleed the rear brake.  That would tell you if the master cylinder is bad(from my experience that is probably the problem).  If that is the case, you can replace it with a $12 Chicom master cylinder.  There are instructions on the retrofit here on the Motobrick site.
  • 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
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Offline SpecialK

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #132 on: August 07, 2019, 10:07:48 PM »
Tested the bike around the block today. Shifted well and felt smooth but the speedometer is not working. I did a search and saw Frankenduck's solution to pull off the cluster, remove the 9 screws and pull the pin connector off then clean the pins, deoxit, and put back.
Hope that works.

I took the instrument cluster out to clean the pins on the speedometer cable. I am assuming that the pins are the three on the ribbon cable in the photo. They looked clean but I cleaned them anyway.
Could there be other reasons the speedo is not working like the connection down at the rear wheel? I'm not sure where to go from here with the instrument cluster. Removing the speedo from the cluster starts getting tricky.
The trip counter does not zero out. The tens place number doesn't turn. That also looks tricky to get out and not sure if it can be fixed or if replacements are available.
The nob for the trip counter was not put in properly from a job by the PO. I have some service records that show the glass was defogged and a couple lights replaced in the early 90's. Anyway, there was a spring and a circlip off the nob but I figured out how it goes back together.

Any help for the speedometer issue would be appreciated before I put it back together.
Thanks.
Speedo 3 pin cable

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Main harness pins look clean

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Thumb wheel from inside with circlip back on

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  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline daveson

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #133 on: August 07, 2019, 10:43:46 PM »
Those three pins were rusty on my non working speedo when I got my brick. I cleaned them,  which fixed the problem, but only temporarily. I did it again, but also gave them a slight twist, to make for a tighter connection, which fixed the problem.
  • Victoria, Australia
  • Current;'86 K100RT Past; '97 Yamaha V Star 650 Yamaha V Star

Offline SpecialK

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #134 on: August 07, 2019, 10:50:09 PM »
Those three pins were rusty on my non working speedo when I got my brick. I cleaned them,  which fixed the problem, but only temporarily. I did it again, but also gave them a slight twist, to make for a tighter connection, which fixed the problem.
I may twist them a little too, just to make sure they are snug. Thanks
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline Laitch

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #135 on: August 08, 2019, 01:13:30 AM »
I am assuming that the pins are the three on the ribbon cable
What's to assume? You're working from a photo with good resolution and clear labeling.

Here are more photos and text, this time concerning the odometer—a part the gears of which seem subject to deterioration. As recommended by the text's author, don't be a nancy:laughing1: although, at the time of the post, he was a bit of a nancy when referring  to himself as a kid even though he was eligible for service in the armed forces, was gainfully employed and likely ready to attempt reproduction at the drop of a pint. Adulthood can be scary, I'll grant him that. Of course, we really will never know the gender behind that post.

Anyway, also remove the sensor from the rear drive and clean it, if you have a screwdriver of the right type.

There's always this outfit for resolution at the end of the day.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline billday

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #136 on: August 08, 2019, 06:52:25 AM »

Forgot to mention; the rear brake is not working. There is fluid in the reservoir but the shoes aren't grabbing. Could be a frozen caliper? Open to suggestions.
Thanks.

Caliper rebuild is not difficult to do.  Search my posts for a pretty recent write-up.

ETA:    http://www.motobrick.com/index.php/topic,12182.msg107307.html#msg107307
  • New York State, USA 10977
  • 1985 K100

Offline SpecialK

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  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #137 on: August 09, 2019, 07:37:42 PM »
Some good news about the nonworking speedometer. It works now! I opened the instrument cluster and cleaned and deoxited the pins, cleaned the pulse generator on the rear drive, and took apart the connector to the pulse generator and deoxited that.
After putting everything back together I tested it by putting it in 2nd gear on the center stand and turning the throttle. I got it up to 20mph and then backed off. The odometer also ticked to the next digit so all seems good for now. I got away easy on that one.

Now on to the rear brakes.
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline SpecialK

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  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #138 on: August 10, 2019, 12:15:57 PM »
This morning I removed the right side footpeg plate and rear brake master cylinder. I have some questions below and labeled photos if you guys could help it would be appreciated.

I believe the MC is shot due to the fact I could not pump any fluid out the rear hose and the corrosion in the photo. I was able to blow air through the rubber brake hose but that will probably need replacement too. There is some corrosion from brake fluid on the inside of the footrest bracket.
MAX BMW has the 13mm master cylinder for about $150. EME has a rebuild kit for $65 https://www.euromotoelectrics.com/product-p/bmckit438.htm
Has anybody tried the rebuild kit? Is it a PITA and do you need any special tools (and patience)? Maybe better to buy the new one?

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Is there any way to remove the BMW crimp on hose clamps without destroying hoses? How does one loosen them to get over the nipple?


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Another unrelated question. I see many hex bolts with a dab of green paint. Is that from the dealer from previous work or maybe it has anti-seize?


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Oh by the way, I can't get any emoticons to insert. I was able at first but now I get a popup window and everything is ?.
Thanks for your help


  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline Laitch

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #139 on: August 10, 2019, 12:56:35 PM »
I can't get any emoticons to insert. I was able at first but now I get a popup window and everything is ?.
We had emoticarnage here through July—emoticons disappearing then reappearing for some members but not for others. Some of the images have been relabeled so if they were in a previous post before their relabeling, now only the text of the image's former label appears. Like with global warming, we'll just need to adapt then die.

Concerning the rear brake cylinder, TMG and Martin have installed inexpensive brake cylinders made in the PRC. They seem to be having excellent results with them. You could join the ranks. Here is the original post describing the adaptation made by Young Engineer. Read through it. Since then, TMG and Martin have added more information in other posts, too.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Laitch

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #140 on: August 10, 2019, 02:18:44 PM »
Is there any way to remove the BMW crimp on hose clamps without destroying hoses? How does one loosen them to get over the nipple?
I see many hex bolts with a dab of green paint. Is that from the dealer from previous work or maybe it has anti-seize?
Those clamps are called Oetiker clamps. They are considered one-time use only. I used side cutters on the pinched tab to cut them loose and didn't damage the hose to which they were attached. I replaced mine with lined nut-and-bolt style but lined worm-drive clamps will work, and many just use plain old hose clamps. The drawback with common perforated clamps is their perforations might damage hoses but you shouldn't be tightening those clamps  with a vein-popping strain anyway. :laughing4-giggles:

The green paint might have been part of a St. Patrick's Day motif but more likely it was somebody's way of keeping track of something. We'll never know. My moto has no green dabs.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline volador

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  • Posts: 300
  • NEEDS MORE CHROME
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #141 on: August 10, 2019, 02:24:39 PM »
Oh by the way, I can't get any emoticons to insert.

We're not missing anything, man. Those bloody emoticons are overrated.
Some hipster probably invented those things and we need to embrace, adapt and use or it's seen as something lacking to get your thought or remark across.

You have a low mileage MC which will easily clean up with some degreaser or whatever your preferred environmentally friendly cleaner.
Use some fine grade Scotchguard to clean cylinder bore if need be.

The kit is a simple fix. One 3mm retaining screw and the piston literally pops right out.
Pre-soak the kit piston in brake fluid to get the rubber pliable.
Pack the replacement accordion cup/rubber boot with some grease to prevent future crud intrusion.
I use standard plumbers high temp grease found at the local plumbing supply or Home Depot, etc..

More MC info
http://www.motobrick.com/index.php?topic=291.0

Oetiker clamp are usually 1 and done use. You may try using needlenose pliers, O-ring remover, a pick or scriber to loosen but its difficult.
A sharp pair of cutters is best for removal



BMW recommended oetiker clamp replacement  17111460862

  • NYC
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY "When Life Throws You A Curve... Lean Into It"

Offline volador

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  • Posts: 300
  • NEEDS MORE CHROME
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #142 on: August 10, 2019, 02:39:34 PM »
Concerning the master cylinder, TMG and Martin have installed inexpensive master cylinders made in the PRC.

If your hanging at the yacht club or lounging in a hammock sipping cool drinks with plenty of spare time on your hands and feeling extra mechanical
 that Chi-com MC could be your next project.  :laughing4-giggles:
  • NYC
  • 1991 K100RS 1993 K75S ABS
5 BOROUGHS SISYPHEAN SOCIETY "When Life Throws You A Curve... Lean Into It"

Offline Martin

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #143 on: August 10, 2019, 04:13:36 PM »
Over 2 years now running the Chicom master cylinder with no problems. As per Volador I pack silicone grease under the master cylinder boot and have done so for over thirty years. I still have my OEM one which I had just re-kitted before the Chicom experiment. Due to it having been packed with grease it has no corrosion. It is important to thoroughly clean out any old brake fluid and coat with a smear of rubber grease internally, before putting into storage. Old brake fluid will eventually crystallize.

Another couple of uses for silicone grease is to smear it around electrical connectors to stop the ingress of water air and road crud. And I am still on my 21 year old fork seals which has had silicone grease packed under the dust covers. Every couple of years I clean out the grease and renew it, if you are riding in dusty conditions I would do it more frequently.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline The Mighty Gryphon

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #144 on: August 10, 2019, 05:31:52 PM »
My advice is to avoid taking a chance on pissing away $65 on a rebuild kit like I did(twice) and just get a $12 Chicom master cylinder and spend an hour or so putting it on your ride.  Then you can spend the rest of your money on fuel to go someplace.
  • 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 SpecialK

  • ^ Motobrick Curious
  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #145 on: August 12, 2019, 02:23:01 PM »
At least I am going to try this: http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/master.leak/master.leak.htm I think this article has been referenced in some other threads. Makes sense to see if I can resurrect the old MC before doing anything else.

Will try this afternoon when I get home.


6:45PM----Ok, took the 3mm screw out but nothing is coming out of the cylinder.  Is the piston and spring supposed to pop out easily? I tried gently tapping, pulling etc. but nothing coming out. I set it in some cleaner for now to see if things loosen up. I don't want to start grabbing things with the needle nose for fear of marring.
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline Laitch

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #146 on: August 12, 2019, 09:18:37 PM »
Ok, took the 3mm screw out but nothing is coming out of the cylinder.  Is the piston and spring supposed to pop out easily?
The piston of a brake cylinder manifesting the condition you have described is unlikely to "pop out". If you're using a brake cleaning compound as a soak, you're on the right track but it might take soaking in Liquid Wrench, PB Blaster or some other elixir to work through the corrosion. Judicious use of compressed air into its inlet might move it out after its soak. A bicycle pump might generate enough pressure if attached well-sealed. Point the cylinder at something that will cushion the piston, absorb its impact, and keep it in the neighborhood when it releases. Remember to use eye protection—perhaps fabricating something out of leather seat covers. Safety glasses and patience should be enough though.

  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline SpecialK

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  • Posts: 99
Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #147 on: August 12, 2019, 10:02:29 PM »
Remember to use eye protection—perhaps fabricating something out of leather seat covers. Safety glasses and patience should be enough though.


They sell those at AutoZone.
  • Wappingers Falls, New York
  • 1987 K100RS
"The first to present his case seems right, till another comes forward and questions him". Proverbs 18:17

Offline The Mighty Gryphon

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #148 on: August 13, 2019, 12:18:06 AM »
If the master cylinder is off of the bike and disconnected from the brake line, you can dissolve the crystallized brake fluid by a short soak in hot water.  After the parts separate, dry them off and blow any remaining water off with compressed air.
  • 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 Laitch

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Re: Awakening 1987 K100RS from 10 year slumber.
« Reply #149 on: August 13, 2019, 08:40:31 AM »
. . . you can dissolve the crystallized brake fluid . . .
Things are looking up, SpecialK! You might have this sorted one way or the other soon.
  • Along the Ridley in Vermont.
  • 1995 K75 72,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Tags: speedometer