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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Classic Motobricks => Topic started by: riots100 on July 23, 2018, 01:43:23 AM

Title: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 01:43:23 AM
Found this 1991 K100RS 4V in southern Utah with only 7200 miles.  It is probably the closest that I'll ever be to getting a new K-bike. 


(http://www.motobrick.com/gallery/1/3537-230718003812-15051523.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003820-15081197.jpeg)


It looks practically brand new.  So we made a deal for the bike and picked her up this weekend and drove back to LA

(http://www.motobrick.com/gallery/1/3537-230718003817-1507246.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003844-1519726.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003821-1508232.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718005833-1532434.jpeg)


It looks great in the right kind of light

(http://www.motobrick.com/gallery/1/3537-230718003845-15201632.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003848-15211102.jpeg)


It is a very clean bike down to the smallest of items

(http://www.motobrick.com/gallery/1/3537-230718003841-15171729.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003824-15101465.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003829-15122328.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003828-1512865.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718003834-1514507.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718005832-1531116.jpeg)

(http://www.motobrick.com/gallery/1/3537-230718005830-15302057.jpeg)


It even came with the original dealer Standup plaque

(http://www.motobrick.com/gallery/1/3537-230718005633-15291087.jpeg)


The tires are almost brand new, all the rubbery components look and feel nearly new and the fuel pump/tank is in great condition.  The pre-purchase shakedown ride was uneventful and the cooling fan kicked on right when is should according to the temperature gauge.  Brake lines are flexible and crack free.

There are only two known issues with the bike:  the ABS doesn't work (ABS light is on) and there is leaky left fork seal.  Right above the leaky fork seal, there is a black smudge on the fork tube that will not clean off.

(http://www.motobrick.com/gallery/1/3537-230718005833-1533509.jpeg)


I want to fix the known issues, perform preventive maintenance for issues that this bike is known to have and then ride the heck out of it.

Known Issues:
ABS I fault light is on and ABS is non-functional - I will want to restore full ABS functionality on this bike.  I need to read up on ABS reset and fault codes to narrow down the likely culprit.
Leaky left fork seal - not bad, but it is there.

Preventative Maintenance:
Oil change - I was thinking of putting in 20W-50 Synthetic
Brake fluid flush and bleed - after the ABS fix
Large hose clamp near exhaust collector to prevent the known issue of cracking welds
Check air filter and if needed, replace
Change fork oil - after fork seal fix
Add Headlight relay harness from Eastern Beaver
Rear view mirror leashes
Side cover leashes

I would be interested in hearing thoughts about checking the splines on the drive shaft and final drive given the low milage and age of the bike.



Title: Re: New old 1991 K100RS 4V
Post by: Martin on July 23, 2018, 02:59:47 AM
Excellent pickup. :clap: Before you replace the fork seal try using a Seal Mate. They can be bought or made from a soft drink bottle. If the seals are hard try Jo's method, soak a rag in ATF and wrap it around the seal and let it soak.

Regards Martin.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on July 23, 2018, 03:23:19 AM
Brake fluid flush and bleed - after the ABS fix
Consider doing the flush, bleed and sensor gap check first. That might fix it.
Title: Re: New old 1991 K100RS 4V
Post by: Scott_ on July 23, 2018, 07:03:18 AM
Congrats on the bike, it sure does look pristine.

At that age, I personally would consider replacing ALL of the rubber bits, fuel lines, brake hoses, vacuum lines, etc......
As far as the splines go, being a paralever bike the FD splines and transmission output shaft splines don't wear much if at all. The wear points will the the drive shaft intermediate spline(middle of shaft) and the clutch splines.
If you pull the transmission to check the clutch splines I would plan on replacing the clutch nut o-ring. If it isn't leaking now, it will shortly. Death of this o-ring is more related to age, not mileage.
Check the heatsink paste on the ignition amplifier, most likely dried up.
Not sure you may find 20-50 synthetic, but I've been using 15-50 and not had any issues.
As far as the ABS, it's possible that the motors and relief pistons/valve could be stuck from sitting for years.
Title: Re: New old 1991 K100RS 4V
Post by: rbm on July 23, 2018, 07:10:07 AM
Congratulations of finding a good specimen of a K100-4V.  Please please please resist the temptation to strip the poor girl bare and go at her with a cutoff tool.

The tires may look pristine however the rubber compounds used in their construction may have deteriorated and hardened.  Check the date code on the tires and, if they are greater than 5 years old, consider replacing the tires.  Bridgestone T30 Battlax 110/80ZR-18 front and 150/70ZR-17 rear are good choices for that bike.
Title: Re: New old 1991 K100RS 4V
Post by: The Mighty Gryphon on July 23, 2018, 08:20:19 AM
Boy, that's a really nice bike.  Are you going to build a cafe or a scrambler?  How much do you want for the fairing and belly pan when you strip it?

I'm with the other posters regarding the tires.  Hoses and other bits could wait until you have some miles on it, depending on how it was stored they may still have a fair bit of life left in them.  Definitely change all the fluids, especially the brake fluid.  It may be necessary to run a couple quarts of DOT 4 through the system to completely clear out the old crystallized fluid.  With any luck, sitting in dry Utah will have prevented any corrosion in the rear master cylinder.  Just be gentle when bleeding to avoid damaging the rubber seals in the brake system.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on July 23, 2018, 08:51:45 AM
Your moto has a Euro headlight switch on the right side, too. You might some German spec model components, based on this video from Chris Harris.
https://www.youtube.com/watch?v=MA6G3vISetI (https://www.youtube.com/watch?v=MA6G3vISetI)
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 09:56:14 AM
Boy, that's a really nice bike.  Are you going to build a cafe or a scrambler?

I am not going to turn this machine into anything other what she already is.  It will remain a stock BMW K100RS 4V.  To do anything else to this pristine specimen would be an aesthetic travesty.  The only thing that I would consider doing would be to replace the fairing with one from an 1100RS.  I do like the look of that bike quite a bit.  Spec wise, the two bikes seem to be almost identical.  I also may replace the seat with an aftermarket one.

Although the Metzlers look in excellent condition, the date code is 3412.  So they look to be just over 5yrs. old.


Your moto has a Euro headlight switch on the right side, too. You might some German spec model components, based on this video from Chris Harris.

Yea I saw this video as well.  According to the video, the items on my bike that match the German spec are:
- headlight switch
- motronic connector color (white)
- power outlet plate (single outlet, aluminum)
- Bilstein rear shock

The video also indicates that the 1100RS fairing was an option for the K100RS.  So fitting the 1100RS fairing would keep the bike on the stock side of the equation.

If the seals are hard try Jo's method, soak a rag in ATF and wrap it around the seal and let it soak.

Where would I find Jo's fork seal restoration method in more detail?  It's worth a shot.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on July 23, 2018, 10:28:50 AM
Where would I find Jo's fork seal restoration method in more detail?  It's worth a shot.
Read this (http://www.motobrick.com/index.php/topic,2098.msg11129.html#msg11129) and the entertaining and informative posts attached to it.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 11:35:37 AM
Read this (http://www.motobrick.com/index.php/topic,2098.msg11129.html#msg11129) and the entertaining and informative posts attached to it.

Entertaining and informative, I may have compromised the seal due to fork compression while trailering the bike. Rats.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on July 23, 2018, 11:47:04 AM
Entertaining and informative, I may have compromised the seal due to fork compression while trailering the bike. Rats.
You might have, but the treatment johnny describes is possibly an antidote. Give it a try. It's next to effortless.
Title: Re: New old 1991 K100RS 4V
Post by: Chaos on July 23, 2018, 11:58:42 AM
Love the bike.  And it's a survivor, K1 in RS clothing. 
Title: Re: New old 1991 K100RS 4V
Post by: Filmcamera on July 23, 2018, 12:36:28 PM
Great looking bike, congratulations.


As well as the other things mentioned above I would fit mirror tethers to the mirror pods and another set to the glass.  Both these parts are now very hard to find and the mirrors have been known to pop off quite easily, my tethers have saved me at least four or five times.


I fitted a K110 RS faring and it is a pretty straight forward job.  I like the look of it as well but have to say now that I have owned the bike a while I am actually considering going back to the standard fairing, the look of the engine is growing on me I guess.
Title: Re: New old 1991 K100RS 4V
Post by: Skunky on July 23, 2018, 03:21:50 PM
Very Nice  :2thumbup:
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 06:46:25 PM
Ordered the braided stainless steel brake line kit. 

measured front ABS sensor gap: 0.48mm (0.35mm - 0.55mm spec.) measurement falls within spec.
measured rear ABS sensor gap: 0.70mm (0.35mm - 0.65mm spec.)  seems to be a little loose, measurement falls outside spec.

I'm going to check the ABS diagnostic codes to see if it correlates with my observations.
Title: Re: New old 1991 K100RS 4V
Post by: The Mighty Gryphon on July 23, 2018, 07:45:57 PM
I put the 1100RS fairing on my bike as well.  Was very straightforward.  I only needed the lower panels with the knee pads and the belly pan.  I kept the original battery covers.  No big deal if you can't get the rear bracket for the belly pan, I made my own from a chunk of stainless sheet.  The rest of the mounts are the same as the old fairing.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 08:24:44 PM
I only needed the lower panels with the knee pads and the belly pan.

The knee pads are the black inserts that fit between the tank and fairings?
Title: Re: New old 1991 K100RS 4V
Post by: The Mighty Gryphon on July 23, 2018, 08:29:48 PM
Yep, there are some subtle differences between them in the lower attachment point that prevents you from using the earlier version.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 23, 2018, 08:54:53 PM
Any one had any luck with Speed Bleeders (http://www.speedbleeder.com) as outlined here? (http://www.motobrick.com/index.php?topic=1135.0)
Title: Re: New old 1991 K100RS 4V
Post by: Skunky on July 23, 2018, 11:02:20 PM
What a speed bleeder does is stop the air from going back into the system when you release the brake. The same can be achieved by locking the bleeder before releasing the brake. The sequence should be as follows.

Loosen Bleed nipple a quarter turn - apply brake - tighten nipple - release brake - repeat until bubbles stop. You can do this on a bike because its all within reach.

However if you find it difficult to reach you could use a speed bleeder or an in line one way valve kit which are re-useable and half the cost of a Speed Bleed. Or less if you get one from China

https://www.ebay.com/itm/ONE-MAN-BRAKE-CLUTCH-BLEEDING-KIT-TOOL-BLEEDING-TUBE-ONE-WAY-VALVE-MLR-BME/123006758701?hash=item1ca3c62f2d%3Ag%3A8cAAAOSwm9JaoUWq&_sacat=0&_nkw=one+way+brake+bleed+&_from=R40&rt=nc&_trksid=m570.l1313

https://www.ebay.com/itm/Cars-Motorcycle-Brake-Bleeder-Clutch-Bleeding-Hose-Tool-Kit-One-Way-Valve-Tube/162890858838?hash=item25ed0d4156%3Ag%3AnYMAAOSwPkBaeroM&_sacat=0&_nkw=one+way+brake+bleed+&_from=R40&rt=nc&_trksid=m570.l1313



Title: Re: New old 1991 K100RS 4V
Post by: Skunky on July 23, 2018, 11:10:31 PM
I guess the advantage of the one way valve over the speed bleed is that you can see if there is still air in the tube before the valve where with the speed bleed its just guesswork.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on July 24, 2018, 05:33:07 AM
I guess the advantage of the one way valve over the speed bleed is that you can see if there is still air in the tube before the valve where with the speed bleed its just guesswork.
If air is present in the system, it can be seen in the stream of brake fluid using the speed bleeder when the brake lever or pedal is pressed, just like when a standard bleed valve is opened then closed. When air is no longer visible, the bleeder is tightened and the fluid topped up. If the lever pressure is good the job is finished, just like when using a standard bleed valve. I have them mounted fore and aft. The speed bleeders cost me around ten dollars each as part of an Aerostich order years ago.

So far so good.
Title: Re: New old 1991 K100RS 4V
Post by: Barry in IN on July 24, 2018, 02:30:53 PM
That is just beautiful.  A time capsule and extremely versatile and useful motorcycle. 
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 26, 2018, 12:27:07 PM
You might have, but the treatment johnny describes is possibly an antidote. Give it a try. It's next to effortless.

Cleaned up the forks and performed the Johnny treatment with ATF.  Rode the bike over the last couple of days and haven't observed any fork oil leakage.  Hopefully I dodged that bullet.
Title: Re: New old 1991 K100RS 4V
Post by: billday on July 26, 2018, 10:06:24 PM
Brother, we all look great in the right kind of light.

That is a beautiful motorcycle,  enjoy!
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on July 26, 2018, 11:27:48 PM
Shimmed up the rear ABS sensor, reset the ABS computer twice, ABS light extinguished.  Bike now has full functioning ABS I brakes.  (I didn't dare test the front though...)
Title: Re: New old 1991 K100RS 4V
Post by: mophead on August 05, 2018, 02:03:01 PM
Nice find.  The K1100RS bodywork will be hotter than the stock you have now.  Had one of these and it served me well.  Just service it and ride it.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 06, 2018, 12:07:23 AM

I added a mirror leash for the left side mirror.  The right side bracket had a missing mirror post, so I ordered a new one and am awaiting delivery.

(http://www.motobrick.com/gallery/1/3537-050818233205-16292231.jpeg)
(I hope to never see this while I am riding)

I flushed the rear brakes, added new stainless steel rear brakes lines and then bled the rear brakes.  The fluid in the rear reservoir was light colored and clean.  I flushed it anyway and you can see the debris that came out.

(http://www.motobrick.com/gallery/1/3537-050818233203-16271950.jpeg)

(http://www.motobrick.com/gallery/1/3537-050818233204-162825.jpeg)

I pulled the tank back to get at the front brake line that goes from the front master cylinder to the hard line junction going back to the modulator in anticipation of installing the front stainless steel brake lines.  I noticed a few things about what's under this tank that I didn't have on my K75.

There are two overflow lines coming from the bottom of the tank.  One line just slips on a tube spigot coming from the bottom of the tank and goes drains to the rear master cylinder area. I assume that this is the line that drains fuel and water from the tank cap area.  The other line is held onto the tube spigot on the tank with a hose clamp.  That line then runs down to a one-way valve, then down to the same area near the rear master cylinder.  What is the purpose of this second drain line from the tank?

(http://www.motobrick.com/gallery/1/3537-050818233207-16301782.jpeg)

On pulling the tank back, I saw that there is large rubber grommet that goes between the tank and frame, and that the bottom of the tank had some thick, heat reflecting material glued on.  It looks like it came from the factory. (a factory Johnny blanket perhaps?)  There is also an empty plug that is circled, what purpose does this serve?

(http://www.motobrick.com/gallery/1/3537-050818233209-16321608.jpeg)

And now for the main issue.  The aforementioned brake line from the front master cylinder terminates at a junction into a hard line going to the modulator.  That junction is buried very deep in the wiring loom below the tank, and sits under the tank mounting brackets/grommets on the frame. It is very hard to get to with a wrench and can anticipate many difficulties in removing the old line and installing the new one.

(http://www.motobrick.com/gallery/1/3537-050818233208-16311906.jpeg)

Is there a better/easier method to get to this brake line junction?

As I am getting deeper into this bike, I am more amazed at how clean everything is and the "like new" condition of all the parts.  I am beginning to doubt that I am needing to even replace the brake lines. (despite the gunk that came out from the flushing of the rear lines)


Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 09, 2018, 12:41:18 AM
I finished up all the brake work.  I got the stainless steel lines on the front.  I put about 4-5 reservoir's worth of brake fluid through each system.  Hopefully that should be enough to have flushed the system. 

(http://www.motobrick.com/gallery/1/3537-090818003025-16351472.jpeg)

(http://www.motobrick.com/gallery/1/3537-090818003025-16341486.jpeg)

To get at the brake line junction under the tank, I had to remove the white retaining clamp that held down the two rigid lines to go to/from the modulator.  Then the line had enough play in it that I could get a wrench around each end.

(http://www.motobrick.com/gallery/1/3537-090818003027-16361749.jpeg)

Changed the oil with synthetic 20W-50. I'm going wait for the Eastern Beaver Headlight relay to come from Japan before I put the tank back in place.

(http://www.motobrick.com/gallery/1/3537-090818003029-16371536.jpeg)
Title: Re: New old 1991 K100RS 4V
Post by: The Mighty Gryphon on August 09, 2018, 10:18:48 AM
While the tank is off and you're waiting for the headlight relays you can wile away some time by adding a manual fan switch and maybe some LED driving lights to help the cagers see you.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 16, 2018, 12:02:05 AM
Got the bike back together.  I plan on installing aux driving lights, but I haven't decided where I want to mount them yet.  The common places seem to be on the lower forks, near the brake calipers or under the front fairing.  I will want to make any mounting look like it came from the factory.  The headlight relays are in and working.  The headlight seems a tad brighter.

The brakes feel the same but at least there is fresh fluid and new lines.  All the other rubber hoses look new and the bike runs like a champ.  Although, while riding around last night, I noticed that the instrument light for the fuel gauge is not working.  I assume that there is one, since I see the fuel temp gauge all lit up.

I'm going to do another shakedown ride along Mulholland Highway on Saturday.  I'm thinking that she is good to go and that I'll tackle other issues as they come up.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 21, 2018, 12:31:21 PM
Weekend shakedown ride complete.  The bike is in perfect working order. 

We went through a tank of gas in the Santa Monica Mountains and along the beach.

(http://www.motobrick.com/gallery/1/3537-210818122856-16381546.jpeg)
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on September 19, 2018, 01:06:49 AM
After some normal freeway riding, I'm getting some fuel weep-age from the top of the fuel tank around the filler cap.  The days have been warm but not excessively hot.

telltale fuel trails emanating from the fuel cap.
(http://www.motobrick.com/gallery/1/3537-190918005033-16791361.jpeg)

The fuel would run down tank to the knee pads
(http://www.motobrick.com/gallery/1/3537-190918005031-16781506.jpeg)

Nothing like this has occurred with my K75.  I took off the filler cap and examined the area around the filler hole and the inside of the tank.  All the plumbing is correct and in good shape.  I did notice some powdery deposit deterioration between the fuel cap and the tank itself.  I wonder what could be causing this mild fuel leak?

My best guess at the moment is that the fuel vapor is making it past the gaskets in the filler cap and condensing back to a liquid state and running down the outside of the fuel tank and down the side of the bike.  Any other thoughts?

When I popped of the cap and looked inside, I did notice some corrosion of the metal on the inside of the tank.

(http://www.motobrick.com/gallery/1/3537-190918005033-1680870.jpeg)

(http://www.motobrick.com/gallery/1/3537-190918005029-167372.jpeg)

corrosion around the sending unit
(http://www.motobrick.com/gallery/1/3537-190918005034-16802031.jpeg)

Are these areas of corrosion something that I should address?  And if so, what would be the best practice to remove this corrosion?
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on September 19, 2018, 06:28:34 PM
. . . My best guess at the moment is that the fuel vapor is making it past the gaskets in the filler cap and condensing back to a liquid state and running down the outside of the fuel tank and down the side of the bike.  Any other thoughts? . . .
When I popped of the cap and looked inside, I did notice some corrosion of the metal on the inside of the tank.
Are these areas of corrosion something that I should address?  And if so, what would be the best practice to remove this corrosion?
Purchase a fuel cap gasket kit (16119062461] from BMW and replace the cap's internal gaskets. The gasket (16111453690) around the fuel tank cap opening is a separate component. Replace that after you've cleaned off the rim where it is mounted.

You could remove and clean the sender per robmack's technique. (http://www.k100-forum.com/t9265-messing-with-the-in-tank-fuel-sender)
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on October 01, 2018, 12:05:23 AM
Finally received the fuel filler gasket set. The original parts had deteriorated with age and proximity to noxious fumes. This Video from Chris Harris helped quite a bit in getting the spring preload and positioning correct for assembly.
This Video from Chris Harris (https://www.youtube.com/watch?v=Mwpt9IumBCc)

(http://www.motobrick.com/gallery/1/3537-300918235237-1739596.jpeg)

(http://www.motobrick.com/gallery/1/3537-300918235236-17391388.jpeg)

We'll see how well it works in fixing the fuel seepage problem with a full tank of fuel on a moderately warm day.  We should have plenty of those left here in SoCal!
Title: Re: New old 1991 K100RS 4V
Post by: natalena on October 01, 2018, 11:16:50 AM
Needed to mow the lawn ... so skipped that, and made a heat shield from a Domino's Pizza box and 3M 3350 aluminum tape. Rode around a bit, and by "the seat of the pants" measurements, it looks like the tadpoles are still swimming. Best part is, the board is covered on both sides with tape, so there's plenty to make a hat in case Chaos Inc. is trying to read my mind.

opps, sorry, meant for this to be under "what I did with my brick..." Damn interweb computee stuff.

*just reported myself to the moderators. Awaiting FBI investigation.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on October 01, 2018, 12:22:30 PM
No worries, I don't mind the thread hijack!

I'm guessing that this was to mitigate heat transmission through the seat?
Title: Re: New old 1991 K100RS 4V
Post by: natalena on October 01, 2018, 08:31:05 PM
No worries, I don't mind the thread hijack!

I'm guessing that this was to mitigate heat transmission through the seat?

Thanks for the forgiveness. Yep, it was very toasty this past summer with the engine heat funneling straight to the seat pan. Concept tested some R30 insulation which worked great (like the Johnny blanket), but was cumbersome to deal with. I'd guess the cardboard heat shield drops the "real feel" on the seat by at least 20f, enough where the heat isn't noticed at all.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 08, 2020, 11:32:40 PM
I finally finished doing some update work to my K100RS.  A while ago I purchased an RS fairing kit from TMG.  Not only did he send the fairings, but all the other parts and bits that would be needed, so much appreciated!

It has taken a while because the fairings would need to be painted to match the color of the bike.  I decided to take on the painting task by myself.  I wanted the paint work to be good and cheap. (so it wasn't obviously going to be fast)  A buddy from work who had some auto body painting experience, would be my mentor and helped out when things got more complex. (like the clear coat) 

I wanted the paint and body work to look good from 12 inches, and the color to be an exact match.  This meant that we would have to lay down a gray prime coat since the final color is affected by the prime layers. (we learned this the hard way)

The fairing panels were in good shape and only required some fill in where there some deep pebble and rock hits. (mostly in the belly pan) I learned that the way to get good paint is in the prep.  The painting is easy, the prep is hard.  I wet sanded again and again.  A few times I messed up on a paint layer and had to wait for it to dry and then sand it all down again.  My hands were wrinkled and sore from all the wet sanding.

This process dragged on for months and months, but we finally finished and I installed the newly painted fairings.

The Primer layer
(http://www.motobrick.com/gallery/3/3537-080820225032-3347851.jpeg)

Factory match paint from the local Auto Body Paint Supply
(http://www.motobrick.com/gallery/3/3537-080820225036-3349128.jpeg)

(http://www.motobrick.com/gallery/3/3537-080820225036-33492081.jpeg)(http://www.motobrick.com/gallery/3/3537-080820225038-3351454.jpeg)
(http://www.motobrick.com/gallery/3/3537-080820225039-3352387.jpeg)
The Install
(http://www.motobrick.com/gallery/3/3537-080820231434-3357502.jpeg) (http://www.motobrick.com/gallery/3/3537-080820225042-33541250.jpeg)

I also figured out a way to discreetly install a pair if high intensity LED driving lights just under the front cowling:
(http://www.motobrick.com/gallery/3/3537-080820225039-3352250.jpeg)
(http://www.motobrick.com/gallery/3/3537-080820225042-33542028.jpeg)

The finished look
(http://www.motobrick.com/gallery/3/3537-080820225044-33551404.jpeg)
(http://www.motobrick.com/gallery/3/3537-080820225032-33472360.jpeg) (photo by Victory Jon)

I really like the look of these fairings, the bike has a clean, aggressive look that I prefer.  I am proud to say that this paint job will stand the 12 inch inspection and is a dead nuts color match.

It was a long, laborious process.  We got side tracked quite a bit with Covid19 lockdown.  It hit us hard and we had to think fast to keep the shop open and people working. We also lost a couple of elder statesmen of our business to the virus.

I would like to thank TMG for providing me the fairings and all the other bits and pieces and my work buddy/mentor for his time in teaching me.  I'm pretty pleased with the result.
Title: Re: New old 1991 K100RS 4V
Post by: volador on August 09, 2020, 01:00:42 AM
Outstanding work. Moto looks stunning!

Whose SS brake line kit did you install?
Title: Re: New old 1991 K100RS 4V
Post by: Barry in IN on August 09, 2020, 01:02:22 AM
That is beautiful. 
Title: Re: New old 1991 K100RS 4V
Post by: The Mighty Gryphon on August 09, 2020, 12:49:18 PM
Very glad I could help you out.  You have done an absolutely stunning job on your bike.

Well done!
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 09, 2020, 12:52:53 PM
Whose SS brake line kit did you install?

I installed the stainless steel brake lines from Spiegler. (https://spieglerusa.com)
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 09, 2020, 09:17:25 PM
While I have some of your attention, I'm having trouble figuring out how to mount the new Battery Covers.  I've searched the forum and the manual and can find precious little on battery cover mounting.

The old style, triangular covers attached at the cowl, on the tank with a rubber grommet and a soft frame mount at the bottom.

(http://www.motobrick.com/gallery/3/3537-090820211336-33651320.jpeg)(http://www.motobrick.com/gallery/3/3537-090820211342-33691547.jpeg)


The larger RS style battery cover seems to mount in three places as well, at the cowl, the soft frame mount in the middle, and on a peg protruding from the knee panel.


(http://www.motobrick.com/gallery/3/3537-090820211341-33672233.jpeg)(http://www.motobrick.com/gallery/3/3537-090820211336-336551.jpeg)(http://www.motobrick.com/gallery/3/3537-090820211339-33671083.jpeg)


Am I correct in assuming that those are the only three mounting points?  That these larger battery covers do not have a mount point in the grommet on the tank?

Also, I seem to not understand how the cover mounts to the rear cowl.  In looking at the cover, it seems that it mounts in a similar fashion to the front mount on the knee pad, but I cannot find any such hardware on the various parts fisches.  How does the cover mount to the rear cowl?
Title: Re: New old 1991 K100RS 4V
Post by: volador on August 10, 2020, 03:41:35 AM
K1100 rear tail cowl has right & left mounting pins for battery cover rear channel/hole slides on to

(http://www.motobrick.com/gallery/3/5332-100820033821-3372336.jpeg)
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 10, 2020, 11:23:09 AM
This is what I was afraid of.  On my K100RS, the rear pins are moulded into the battery cover, not the cowl.  My cowl just has a hole for the pins to slide into.

Are the pins moulded into the cowl itself, or are they a separate part?
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 10, 2020, 12:44:26 PM
On Max's K1100RS parts fiche diagram it looks like a stud is screwed onto the rear of the cover, a short length of vacuum hose covers it then it is friction fit into the tail. Maybe Filmcamera will post up some photos and an explanation.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 10, 2020, 10:00:09 PM
On Max's K1100RS parts fiche diagram it looks like a stud is screwed onto the rear of the cover...

Yes, I saw that too, so ordered two, one for each side.

(http://www.motobrick.com/gallery/3/3537-100820215305-33732106.jpeg)

They are brass and look like it should work, but the place in the cowl where these brass studs would fasten to are not compatible.  The hole in the cowl is about 8mm in diameter and there isn't any surface on the backside of the hole where a backing nut would get any purchase to firmly hold the stud. (and the hole is larger in diameter than the backing nut that came with the stud)  These studs are the same as the ones that are mounting in the knee pads.

I called the Max parts counter to see if they could offer any additional insights.  They came up empty as well.

There is clearly something else missing from this assembly.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 10, 2020, 10:52:57 PM
(and the hole is larger in diameter than the backing nut that came with the stud)  These studs are the same as the ones that are mounting in the knee pads.
There is clearly something else missing from this assembly.
I think that's where the short lengths of vacuum hose that I listed previously come in. I guess they slide over the post to increase its diameter and grip the hole's perimeter to prevent rattling.There's a washer in that assembly, too.
Does your cover look like this one? The post lug on the aft end of yours looks like it's missing half of its surface.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 10, 2020, 11:09:17 PM
I think that's where the short lengths of vacuum hose that I listed previously come in. I guess they slide over the post to increase its diameter and grip the hole's perimeter to prevent rattling.There's a washer in that assembly, too.
Does your cover look like this one? The post lug on the left end of your looks like it's missing half of its surface.

Agreed.  The vacuum hose slide over the smooth part of the stud and fits nicely in the mating "clip" of the battery cover.  It's the same mounting concept on the front end of the cover where it "clip" to a rubber stud that is mounted in the knee pad.

The issue is that I don't see how the brass stud mounts into the rear cowl.  I don't think that a washer is the answer because there is no room on the rear side for even the nut to screw onto the shaft.

My panels look like this:
(http://www.motobrick.com/gallery/3/3537-100820230100-3374847.jpeg)

Similar, but mine seems to be missing a squarish stand-off where there is a square chunk of insulation missing on mine.

I wonder if there was some type of press-fit peg that goes into the cowl.

Clearly I'm not connecting all the dots...
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 10, 2020, 11:20:09 PM
Is that U-shaped molding at the aft end intact? It's indicated by the arrow in the attached image.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 10, 2020, 11:37:11 PM
. . . but mine seems to be missing a squarish stand-off where there is a square chunk of insulation missing on mine.

I wonder if there was some type of press-fit peg that goes into the cowl.
It's missing that stand-off because the stand-off was broken off before you received it. Max indicates a rubber peg somehow mating with that missing element.
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 11, 2020, 12:10:50 AM
It's missing that stand-off because the stand-off was broken off before you received it. Max indicates a rubber peg somehow mating with that missing element.

There is something missing for sure, but I don't think anything was broken.  The battery covers that TMG sent are well intact at the suspect end:

(http://www.motobrick.com/gallery/3/3537-100820234448-3375131.jpeg)

The bike was basically new when I purchased it and the hole in the cowl where the peg should go seems factory fresh, i.e. nothing looks to have been broken:

(http://www.motobrick.com/gallery/3/3537-100820234447-33751118.jpeg)

The missing piece probably wasn't included with the bike when sold because because of the trim package that it included. The smaller triangular covers of the original trim have a peg at the suspect end that inserts into the hole in the cowl with a plastic bushing.

  I am guessing that there was some plastic insert that went into that hole that either had a peg molded onto it or was threaded to allow those brass studs to be screwed in.  Then the rubber vacuum hose was slipped over to receive the cover clip.  The parts fiche seem to be silent on the issue.


Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 11, 2020, 12:32:08 AM
There is something missing for sure, but I don't think anything was broken. 

The missing piece probably wasn't included with the bike when sold because because of the trim package that it included. The parts fiche seem to be silent on the issue.
The fiche seems to be screaming up here. The hose-covered peg goes in that hole.To which missing piece are you referring—the one that seems broken off to me or a different one?

Here's how I see it. The threaded portion of the stud you bought is inserted into the horseshoe molding on the rear of the cover. The stud's smooth part faces to the rear. A washer is placed on the threaded part then the nut is tightened onto the washer. An imprint of a washer is visible on the interior face of the horseshoe. A piece of hose of the type indicated in the fiche is slipped over the smooth length of stud then the assembly is inserted into the hole. I don't how you'll deal with the missing piece.
If I stare at it long enough I can almost see my description working, but not quite.   :laughing4-giggles: The contour of the cover's aft mount seems designed to snap the cover post into place. If the part were a couple of thousand miles closer, I'd be interested to take a whack at fitting it. Speaking of whack, the fiche is selling a meter of submersible petrol hose for the application.  :thisplacewhack At least that gives hint of the finished post's diameter, and extra fuel hose is always useful.
Title: Re: New old 1991 K100RS 4V
Post by: volador on August 11, 2020, 03:42:10 AM
Your 1991 K100RS 4V rear tail cowl is not missing anything, it is not-compatible with K1100 battery covers unless you retro-fit as you have indicated by adding a mounting stud or pin to existing tail cowl side arm holes
or
purchase the K1100 tail cowl which are pretty cheap on Ebay currently
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 11, 2020, 01:02:10 PM
Your 1991 K100RS 4V rear tail cowl is not missing anything, it is not-compatible with K1100 battery covers unless you retro-fit as you have indicated by adding a mounting stud or pin to existing tail cowl side arm holes

This is what I was expecting.  Since I have no desire to paint a rear cowl, it's off to the shop as see what I can fabricate for a retro-fit.

Thanks!
Title: Re: New old 1991 K100RS 4V
Post by: riots100 on August 12, 2020, 10:13:18 PM
Got an 8mm black Delrin Rod from McMaster-Carr for $4.00 for 48", cut it down, drilled and tapped a center hole to accept the brass studs from MaxBMW.  The Delrin block inserted nice and tight into the cowl.  Cut the vacuum tube to fit over the studs and mounted the new battery covers.  The retro fit turned out well, and is reversible in case I want to go back to the old style.

(http://www.motobrick.com/gallery/3/3537-120820220002-33771191.jpeg) (http://www.motobrick.com/gallery/3/3537-120820220002-33772128.jpeg)
(http://www.motobrick.com/gallery/3/3537-120820220004-33791861.jpeg) (http://www.motobrick.com/gallery/3/3537-120820220005-33801114.jpeg)
(http://www.motobrick.com/gallery/3/3537-120820220007-3381873.jpeg) (http://www.motobrick.com/gallery/3/3537-120820220008-33831265.jpeg)
(http://www.motobrick.com/gallery/3/3537-120820220008-33832169.jpeg)

Time to stand down and move on to other things.
Title: Re: New old 1991 K100RS 4V
Post by: Laitch on August 12, 2020, 11:05:22 PM
Got an 8mm black Delrin Rod from McMaster-Carr for $4.00 for 48", cut it down, drilled and tapped a center hole to accept the brass studs from MaxBMW.  The Delrin block inserted nice and tight into the cowl.  Cut the vacuum tube to fit over the studs and mounted the new battery covers.  The retro fit turned out well, and is reversible in case I want to go back to the old style.
Necessity is a mother. Good work!  icon_cheers