Author Topic: 1991 K75S - 30 year major service  (Read 11778 times)

Offline kurtk75s

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1991 K75S - 30 year major service
« on: September 28, 2020, 10:50:50 AM »
I am new here - don't even have enough posts to edit - but I'm starting a project thread to provide motivation to get this thing done. 

A rehash of my 'new member' post:  I've owned this 1991 K75S since 1995 when I picked it up at the local dealer with 2500 miles on the clock.  I put the bags and tank bag on it.  Also added the Fox TC in about 1996.  The bike has 75000 miles on it now. 

My plan is to go through it pretty completely.  New SS brake lines, rotors and pads, splines lubed, probably a new drive shaft - DS splines are worn but the final drive splines looked OK last time I was in there.  I've already done some stuff like new spark plugs and air filter.  I plan on replacing coolant and fuel lines.  Rear master cylinder is leaking.  Small drip from tranny.  And a bunch of things need to be improved:  rattles, non-solid fairing mounting, saddlebag mounts are worn, leans over too far on side stand, add conspicuity lights like Skene, etc.

I'm not a mechanic by any means but I've done a bunch of stuff on bikes - like clutch spline lubes, valve check/adjustment, fork seals, suspension setup and regular maintenance stuff.  We don't have a dealer close to central New York so I've had to learn to be self sufficient since we own 5 BMWs. 

Pictures below are the bike ready for a cross country trip starting in San Diego in 2017, at about 70000 miles.  Then a couple of the bike as it sits this morning.  I staged the wheels and some of the stuff I'm painting.  The black parts are getting shot with appliance enamel.  I like how the forks came out.  The exhaust shield is glossy but better than rust.  I'm not happy with the wheels - but they are just going to get covered with brake dust anyway.

Oh, I want to do something with the seat.  I have always loved that BMW by Corbin saddle.  I've been using RTV to keep it together for about 10 years now.  I know others hate that seat but it works for me. 

  • Syracuse, NY
  • 1991 K75S

Offline Laitch

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Re: 1991 K75S - 30 year major service
« Reply #1 on: September 28, 2020, 10:59:00 AM »
Thanks for the photos.  112350


Are you indicating that the side stand bushing is worn to an extent that the moto is leaning farther than it should, or that the angle of lean is disconcerting?
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Rcgreaves

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Re: 1991 K75S - 30 year major service
« Reply #2 on: September 28, 2020, 01:06:45 PM »
Welcome Kurt:

Given your resume above- you are now a mechanic. To own a Brick it’s virtually a prerequisite 44271

At first glance my recommendation is you review/ study some of the sticky Rebuild thread posts in the classic motobrick forum. If you haven’t already.  One by mlytle was compressive.

 EG from where I sit- the stuff you reference is fine too,but the rubber bits , case breather, fuel pumps damper, master cylinder seals And the lot ..are generally the top line troubleshooting items.... though from the way you phrased it the splines should be a known not an “ok last time I looked”

I drive a 94 abs same color and mileage you lucky dog.. Call/email if I can help/empathize.🙃
  • Livingston in Southwest WI. USA-"With the good earth all around."
  • 94' K75S, 85' GL1200 Aspencade, 96' VFR750F, 01' GL1800. Restoring: 95' K1100RS, 83' R80RT NEW: Motorvation Formula II
Doing “better than I deserve"

Offline kurtk75s

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Re: 1991 K75S - 30 year major service
« Reply #3 on: September 28, 2020, 03:17:47 PM »
Laitch:

I think both.  This bike has always had a lot of lean while on the side stand.  The bushing is definitely worn - or the ears have widened.  I've never done any maintenance to the side stand.  Also, my side stand/clutch lever safety mechanism has been disconnected for a lot of years.  Probably 10 or so.  The nut that connects the side stand rod to the clutch lever disappeared and I never replaced it.

Are you a member of the MOV?  My wife and I have been since about 2016 and we've been to the Goshen rally a number of times.

Rcgreaves: 

There are a lot of things I left out of my original post.  I rebuilt the front MC about 11 years ago and it has been inside under cover all the time except for 2 weeks each year since then.  The K75 was kept in San Diego from 2010 to 2017.  That is why I qualified 'last time I looked'.   About 5000 miles ago I was going to replace the driveshaft with one off of my buddies bike - he carried it in his luggage out to Cali for me.  Turns out my existing driveshaft splines were in a little better shape than his so I just lubed it up and rode it back to NY.  That is the last time I looked.   DS gets lubed every tire change.  My current plan is to get the front end of the bike back together before I start pulling the back end off.  A 'bike full' of parts takes up a lot more room than an assembled bike!

Front wheel bearings have been replaced.  Stuff in the tank has been replaced.  Some fuel line has been replaced.  Since I have it mostly apart, I will replace it all again.   The cooling fan was replaced at the Salem, Oregon MOA rally. 

I'm going to read through a bunch of the rebuild threads like you suggested and will create a spreadsheet of stuff I need to do.  I have a list going - but that is just stuff I know needs to be done:  not preemptive maintenance based on the collective knowledge. 

Thanks for the comments!
  • Syracuse, NY
  • 1991 K75S

Offline The Mighty Gryphon

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Re: 1991 K75S - 30 year major service
« Reply #4 on: September 28, 2020, 03:40:59 PM »
Lots of good experience with restorations in the members here.  I've done two frame up rebuilds myself.  Not much the members here haven't seen.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline kurtk75s

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Monday: Progress Report
« Reply #5 on: September 28, 2020, 06:56:02 PM »
Today I organized my garage a bit to get ready to work on the bike.  In many homes I have seen 'unused treadmill syndrome' - where the treadmill becomes a clothes hanger and storage rack.  My K75 was like that in my garage.  This project started as simply basic maintenance and a major cleaning.  But one thing leads to another and soon you are painting wheels...

I removed the battery, muffler, and bag mounts.  Everyone likes pics so I'll attach a few.  The first is an under seat shot.  The battery tray isn't too much of a mess considering the lack of attention this bike receives.  I wish the rest of the paint was as nice as the red under the seat! 

The second shot shows the condition of the muffler.  Not too bad.  I'll polish it up and try to get the baked on asphalt off.  On the stand there is a small amount of brownish 'flakes'.  That is remnants of an encounter with a massive herd of sheep on the road near Brian's Head, Utah.  There were so many sheep that we stopped on the double yellow, turned off the engines, and just let the sheep flow around us like a river.  They just kept coming for minutes!  At the hotel that evening, we were appalled by the amount of dung our bikes had gathered up.  That was in 2013.  I'm still finding crap!
  • Syracuse, NY
  • 1991 K75S

Offline kurtk75s

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Bag Mount Wear
« Reply #6 on: September 28, 2020, 07:04:24 PM »
I'm pretty good at 'remove and replace'.  It just requires parting with a significant amount of money.  On this project, I'm going to try to fix the old stuff, if possible. 

Here is an example of something I would like to reuse:  the bag mounts.  They are still sturdy but the points where they contact the bags have become really worn and this is probably what is causing my bags to jiggle around while riding.

I'm sure you folks have run across this - what have you done to make things 'tight' again?  My first guess was going to be to use an epoxy like JBWeld.
  • Syracuse, NY
  • 1991 K75S

Offline Chaos

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Re: 1991 K75S - 30 year major service
« Reply #7 on: September 28, 2020, 07:19:52 PM »
  I have always loved that BMW by Corbin saddle. 

I really like Corbin seats, but they don't seem to hold up all that well.  A local car upholstery shop may be able to recover it.  Not sure if Corbin does it anymore.
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline Laitch

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Re: 1991 K75S - 30 year major service
« Reply #8 on: September 28, 2020, 07:30:42 PM »
. .  . what have you done to make things 'tight' again?  My first guess was going to be to use an epoxy like JBWeld.
All sorts of ideas have been deployed.
  • Gluing a foam or thin rubber strip to the case near the latch to exert pressure on the rack when the latch closes and pulls the case to the rack.
  • Restoring the thickness of latch hook's polymer padding or replacing it with some other material, maybe even JBWeld.
  • Using a wooden block and metal stirrup device to keep the latch from opening—like this one.
  • Making a more streamlined latch block assembly—like this here.
  • and others that a search of the site might reveal.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline Rcgreaves

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  • "I'd rather be flying, but this will do nicely"
Re: 1991 K75S - 30 year major service
« Reply #9 on: September 28, 2020, 10:40:37 PM »
Bullet #1 in Laitch’s reply has been quite effective for me.  Previous owner KMEV affixed dense rubber patches on the contact patch giving back a snug fit and fixture that doesn’t vibrate or even rattle icon_cheers 4265249878.  My ride had lots of love
  • Livingston in Southwest WI. USA-"With the good earth all around."
  • 94' K75S, 85' GL1200 Aspencade, 96' VFR750F, 01' GL1800. Restoring: 95' K1100RS, 83' R80RT NEW: Motorvation Formula II
Doing “better than I deserve"

Offline kurtk75s

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Tues, 9/29 progress
« Reply #10 on: September 29, 2020, 07:07:58 PM »
No pictures today but I wanted to at least add an update to show that I'm doing something.

Ordered a bunch of parts from Beemer Boneyard and Spiegler.  SS lines, rotors, pads, fuel line, monkey nutz, clutch cable, fuel pump rubber damper kit. 

Also put some elbow grease into the muffler.  Found a combination that worked pretty well to remove baked on tar and corrosion at the welds:  clay bar with 'Evaporust' as a lubricant!  Worked surprisingly well.  I noticed some dings in the exhaust that just aren't going to get buffed out but I'll try to get it as good as I can.

I also started prepping the painted parts.  More clay bar and rubbing compound to try to get the old paint to shine as good as it can.  I've been reading forum posts to get some tips on how to address some of these cosmetic things.  My belly pan is really worn - thinking of getting a rattle can match and try to refresh the best I can.  I suck at painting.  Maybe my wife will give it a shot.

Tomorrow I'm going to spruce up some of the black plastic parts.  I use a mixture of 50/50 boiled linseed oil and mineral spirits (paint thinner).  Rub it on then buff it out.  Got that idea from a Jeep forum and used it to keep some VWs and a Honda Element looking good.  Gets rid of that chalky look that plastics get with age.  On a car that sits outside, I have to redo every year or two but it is a fast procedure.  Easier than waxing - and that Element had a lot of plastic.  Works great on motorcycles.  The unpainted cases of the K's and Oilheads look like new after an application. 

When the rain stops, I'll dive into the drive shaft.  Spline pictures are always popular.
  • Syracuse, NY
  • 1991 K75S

Offline Martin

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Re: 1991 K75S - 30 year major service
« Reply #11 on: September 30, 2020, 12:36:44 AM »
If you want to keep your belly pan in good condition install a extra long front bucket flap. Five mud flaps and a dog bowl for 90 cents.
 http://www.motobrick.com/index.php/topic,7914.msg57755.html#msg57755    I used to cover the lower parts of my belly pan  with non slip boat deck tape but this required changing every so often, which was a bit tedious. I now spray the lower parts with truck bed liner which can be touched up if and when needed.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline kurtk75s

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Fender Xtend
« Reply #12 on: September 30, 2020, 10:31:58 AM »
Thanks for that link, Martin!  I will definitely do that. 

I'm also pondering my approach for the bag mounts.  I may do many of the options:  a little JBWeld, a rubber pad near the latch AND the block of wood.  Belt and suspenders.  Don't want to lose my skivvies - there may not be a Walmart handy.

Today I am trying to recreate my maintenance records for the K75S.  25 years is a long time - and stuff gets misplaced.  I had a 3 ring binder going for years.  Then I switched to electronic.  But I can't find the files.  Since the K75 became the 2nd, then 3rd, and now 4th bike, it didn't get the love and attention it deserves.  But I did do yearly fluid changes while it was in California (including brakes and tranny/FD).  Coolant only once in 10 years, though.  Tires were replaced every other year.  DS splines lubed with every tire change.  Had to replace the battery once.  It lasted 2 years and died suddenly while on the road in 2017.  The bike was kept on a Battery Tender Jr. 100% of the time.  I need to add some pics - so the one below is of me 'measuring' the battery prior to running into the village of Talahina, OK to try to find a battery.  Failure just happened to be at the Oklahoma BMW riders campout.  I coasted to this spot from the park office in the background.  Within 20 minutes I had a battery charger, a Microstart, and more moral support than I could handle!  The next morning I found a battery at the first place I went into.  Lucky! 

In the records that I dug up, I found that the last time I check the valve clearance was at 51K miles.  It was perfect at that time so I didn't get to use the nifty valve spring compression tool my buddy let me borrow.  Maybe this time...

The reason I'm looking for the history is that the 'easy' fuel line and the crank case breather tube look like they are in REALLY good shape and I'm having this feeling of deja vu - I'm pretty sure I replaced them within the last 12 years.   I'm also second guessing the coolant hoses - based on the anecdotal evidence here and the general appearance (great) of my lines, that is an expensive bit of preventive maintenance - that money could go toward something else.
  • Syracuse, NY
  • 1991 K75S

Offline kurtk75s

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Timberrrr....
« Reply #13 on: September 30, 2020, 10:45:29 AM »
A couple more 'before' pictures.   This illustrates the side stand lean that I will address.  I think the first picture is a bit of an optical illusion.  Or maybe I'm just stupid  4265249878.

The background is Big Bend NP, again in 2017.  Absolutely stunning.

A few more things are coming back to me.  I rebuilt both front calipers and the master cylinder about 12 years ago.  I sure wish I could find the receipts!  I am normally an organized person - but that period of my life was a bit intense. 

  • Syracuse, NY
  • 1991 K75S

Offline The Mighty Gryphon

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Re: 1991 K75S - 30 year major service
« Reply #14 on: September 30, 2020, 11:06:41 AM »
I'll go out on a limb and say your side stand is okay.  I suspect that the amount of lean angle is to lower the seat height to make it possible for someone less than 6'5" to swing a leg over the bike.

Regarding seat height, I'm always surprised at how often I am looking down at the driver of an SUV when I pass them on my RT.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline Laitch

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Re: 1991 K75S - 30 year major service
« Reply #15 on: September 30, 2020, 11:13:08 AM »
This illustrates the side stand lean that I will address.
If the side stand bushing isn't sloppy, consider leaving well enough alone. Have you ever tried to tip over the moto from the side stand position? That's not going to happen. I like it that way. Gryphon's observation is accurate, too. Furthermore, the garden variety peabrain kid who might want to play with your moto when it's parked will be unlikely to have both the ambition and the coordination to lift it or push it over. I usually park the moto on the center stand as further insurance that if Junior is able to mount it, pull in the clutch and inadvertently raise the center stand when playing vroom-vroom while waiting for mommy to return with the groceries, the moto won't fall over when he dismounts.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline kurtk75s

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Side stand
« Reply #16 on: September 30, 2020, 11:29:23 AM »
Thanks for the observations. 

Laitch - There IS quite a bit of play in the side stand.  I never even checked that until you mentioned it.

I was also wondering if the Fox TC has also raised the bike/side stand up a little contributing to the lean. 

My issue isn't with it falling over - it is with trying to get it upright when fully loaded.  I was 28 when I bought the bike.  I'm not 28 any more :(.

Now I almost always put the bike on the center stand when parked.  I used to be able to throw a leg over that bag on the back.  Jan Claude Van Damme style.  Now, with the bike on the center stand, I step on the right peg and then 'step through' over the front part of the seat.  The adaptations we make. 

The seal line dry bag has been a part of my luggage for as long as I can remember riding.  It fits on every bike I have, is waterproof and cost almost nothing.  I used to pack my camping gear in it - but over the years that gear got more expensive and harder to replace.  So now I mostly pack clothes, shoes and such.  That way, if it walks (never has) I'm not out too much cash and the stuff is pretty easily replaced.  The only thing I can't put in a sidebag is the tent.  But I can get another one of those fairly quickly in a pinch.  I also take that bag into a hotel with me - so now I can leave the camping gear in a bag on the bike. 

The orange lashing straps are from Harbor Freight.  I used to use ones with plastic buckles but forgot to bring them on one trip.  Turns out the HF ones work well, are cheap and easily replaced.  Must be careful with metal cam buckle, though.
  • Syracuse, NY
  • 1991 K75S

Offline kurtk75s

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I shouldn't rely on my memory
« Reply #17 on: September 30, 2020, 11:37:38 AM »
I found a few receipts for parts.

Turns out that I replaced the shock in 2001!   At a ridiculous price of $575 from Cal BMW.  I thought I had done that 5 years earlier.  Heck, that thing isn't even 20 years old!

In early 2000 I added heated grips.  I thought I did that when I bought the bike.  Grips were $152.  At that same time I replaced the roundels and also the driveshaft.  Remember when driveshafts cost $173.83?   I'm pretty sure I swallowed hard before coughing that up.


  • Syracuse, NY
  • 1991 K75S

Offline Laitch

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Re: 1991 K75S - 30 year major service
« Reply #18 on: September 30, 2020, 12:02:39 PM »
My issue isn't with it falling over - it is with trying to get it upright when fully loaded.  I was 28 when I bought the bike.  I'm not 28 any more :(.
It sure can be an unwieldy beast when loaded and being maneuvered after a few hundred miles of riding. I just keep the wheels aligned and shove it upright using my right thigh against it and some upper body strength but it would be nice to be 57 again or even 67.  :laughing4-giggles: I'd miss the senior discounts though.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles

Offline mw074

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Re: 1991 K75S - 30 year major service
« Reply #19 on: September 30, 2020, 12:24:53 PM »
I have seen a couple of side stands bend over time. It comes from sitting on the bike while it is on the side stand. If that is the case, it can be tweeked in a press.
  • Michigan

Offline The Mighty Gryphon

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Re: 1991 K75S - 30 year major service
« Reply #20 on: September 30, 2020, 01:41:33 PM »
I have a file drawer full of receipts for parts from the past 6 years.  Some of the parts have had ridiculous increases during that period.

Example:  Tank Badges have gone from a bit over $14 in 2014 to $30.73 today.  And, there will be another increase in a few months($33?).  For a while, they were raising prices by as much as 8% twice a year.  All while inflation was running at around 2%.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline kurtk75s

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Parts
« Reply #21 on: September 30, 2020, 05:02:29 PM »
MG - I just found a receipt from 2000 where I had purchased emblems:  $7 for the tank, $6 for the tail. 

The stuff I ordered yesterday from Beemer Boneyard arrived today!  Wow.  I have always received great service from them. 

Here is a pic.  The EBC rotors look a little different - especially the pins on the 'abs ring' side. 

  • Syracuse, NY
  • 1991 K75S

Offline kurtk75s

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Black Plastic Cosmetics
« Reply #22 on: September 30, 2020, 05:07:31 PM »
Here is the result of the boiled linseed oil and paint thinner process.  Yes, it does smell like linseed oil for a while after application (like weeks).  If you do this, be careful with the rags - I understand linseed oil rags are one of those 'spontaneous combustion' items. 

The first picture is the 'before' of the rear fender I took off yesterday. 

The second is the 'after.  I sure hope it is obvious.  There are still scratches and dings but, other than the wear, it makes the plastic look pretty good.  I will give it another buffing tomorrow after it dries a bit.

  • Syracuse, NY
  • 1991 K75S

Offline kurtk75s

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Windshield pads
« Reply #23 on: September 30, 2020, 05:13:23 PM »
The rubber-ish pads under my windshield disintegrated when I pulled the windshield off (to clean - and to get the bike to fit where I have it in the garage).  I was moving some stuff around in the basement and found a toolbox drawer liner that I hadn't used.  Hmmm.  Wonder if that would work.  Looks like it will.

  • Syracuse, NY
  • 1991 K75S

Offline Martin

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Re: 1991 K75S - 30 year major service
« Reply #24 on: September 30, 2020, 06:05:53 PM »
I bolted a slice of boat trailer roller to my side stand foot to make it easier to get it up right. This was useful especially when parked on the side of the road as you also have to counter the camber of the road. Probably not as much of a problem with LH drive roads. I changed the original curved leg stand to a straight leg stand and I didn't have to fit the 20mm thick foot extension. I've just fitted a 20mm cast aluminium foot to a mates brick. He had tried a hockey puck but got it wrong.
Regards Martin.

* Side stand reduced image.png (178.53 kB . 400x300 - viewed 777 times)
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

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