Don Eilenberger's THE '87 K75S

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THE K75S, 1987 model with a few modifications

Click on photos for larger view

As of 11/15/2006 - THE K75S is heading back to a former owner - Klaus Hueneke bought it from me. And I bought an R1150RS to replace it.

Update - as of 04/2007 - Harold Gantz bought THE K75S from Klaus.. the bike has roots in the NJ Shore BMW Riders club and seems reluctant to leave. Which is OK - I have visitation rights.

Mac Kirkpatrick purchased it on 1/4/89 from John & Rhonda McLaughlin, Palm Harbor, FL for $4100 with 6000 miles on it.

With bags and mounts, electric outlet, dual horns and flashers.

Over the years, Mac Kirkpatrick added

  • Corbin seat (blue piping to match BMW Roundel)

  • Used top box.

  • K75 knee pads on tank.

  • Heated grips.

  • Rear rack.

  • Stainless steel front and rear brake lines.

  • Ferrodo pads. (Later went to Dunlop pads.)

  • Fork boots by Rancho suspension.

  • Fox Shock. (replaced by DJE with a WIlbers shock)

  • SOS Priority lights.

  • New speedometer, adjusted odometer mileage to reflect true mileage.

  • Installed ETM headlight modulator. (ETM ="Emergency Traffic Mover". Basically a police car headlight modulator modified for use as a headlight-modulator. This eliminated the need to have a DOT mandated bulky device on the handlebar to sense when dusk arrived.) (DJE removed this and all remnants of the wiring for it - it was replaced with a KisanTech modulator)

  • Modified throttle switch. (Enriches sooner as throttle opens.)

  • Keyed, newer style bag locks, match ignition.

  • Pin stripes by Kent Holt. Blue color meant to match the blue color in the BMW roundel. (Holt also did all the paint on the bike)

  • Installed dual horns again. Not sure why.

  • Front and rear running lights.

  • K & N air filter. (this was replaced with a stock filter by DJE)

  • Polished stainless nuts & bolts. Custom made valve and crankcase cover bolts and "washer" on front axle.

  • Big valves, milled head, ported and polished head (at 35,335 miles).

  • Modified center stand to clear wider rear rim. Powder coated center stand.

  • Grease fittings on side and center stand. (Some parts from K1).

  • Installed fuel and temperature gauges.

  • Muffler heat shield repainted by Kent Holt.

  • 100/60 headlight bulb.

  • Glass beaded footpeg mounts to make all metal color, no paint.

  • (Polished part of the footpeg brackets, alternating every other "flat" . Made bike more symmetrical/even with polished rims.)

  • Added ABS. BIG job. 

  • Front forks powder coated.

  • Jerry Sullivan of Vacaville, CA polished the rims, including the insides of the wheel spokes (dirty intensive job.) The wider rims are for a '91 K100RS 4 valve

  • Radial steel Metzelers installed. 60 series on rear..

  • Installed a 700 watt alternator from a K100RS before the KRS was sold.

  • Valve and crankcase covers bead blasted. Ribs and logos polished.

Mac sold it to Klaus Hueneke on 10/12/00 with 44,300 miles on it. Included bags, bag liners, tank bag and top box. Klaus sold it to me on 08/20/02 with almost exactly 45,000 miles on it (300 of which were my miles on it in Canada)


So far I've done, or ordered:

  • New windshield - old one has star cracks around the mounting holes

  • Changed all fluids

  • New battery by Klaus (the old one went dead in Canada)

  • Installed HeatTroller from Gerbing for electric jacket liner

  • Polish, polish, polish by hand with 3M Mirror Glaze, followed by Simonize

  • Repair of wiring - mechanics are awful when it comes to electronics

  • Rear driveshaft lube. Looked fine, was dry but not worn

  • Clutch adjustment - cured a rough shifting tranny

  • FuelPlus+ computer going in (it's here - will do in a week or so)

  • Reflective thingies added to rear bags (photo) - no stickers on these bags.

  • Replaced alternator drive rubbers (monkey nutz)

  • Coolant/thermostat change and flush

  • WIlbers shock installed

Update 10/11/2002

  • Replaced radiator with no-miles spare (wasn't actually needed)

  • Added Kisan-Tech headlight modulator to replace the one past owner had installed

  • Did spline lube - clutch and driveshaft. Splines in excellent condition

Update 11/28/2002

  • Miles on it now 47,200 +

  • Adjusted steering head bearings - they were close, but not quite right

  • Installed CC Products cover over the fuel rail (keeps it clean and makes it look clean)

  • Installed the Fuel Plus+ a while back (Brian Curry came over, and he loves doing this job)

  • Replaced coolant temp sensor (was reading wacky)

  • Installed headlight relays - was getting 1.0V drop between the headlight high-beam (60/55w) and the battery. Am now getting 0.10V drop and lots more light.

  • Added GS style handguards for winter riding

  • Added bubble mirrors (1.5"D) to mirrors - cured the lane visibility problem on the slab

  • Added 3M StoneGard to the leading edge of the belly pan - this is an area where rock chips love to form. It is really hard to see the 3M stuff once it's installed right (cost was $10.. way cheaper than a repaint and pinstriping, and since the paint was redone not long ago - it's currently perfect). Took about 10 minutes to apply once I made a pattern and cut them out.

Planning to do (two weeks in January)

  • Rear wheel has a slight wobble - send to get straightened.

  • Figure out which front rotor has a warp in it - straighten or replace ( UPDATE: have checked the rotors and 'adjusted' them - they are now perfect, but pulsing remains. I've ordered new stock pads, and will try to expose a new surface on the rotors before installing the new pads. I believe there are some hard-spot deposits on the rotors causing the pulsing feeling - which can't be felt in the brake lever itself.)

  • Get tank bag rebuild (again) by Bob Weis

  • Replace pad on bars - have a slightly longer one which will fill a 1/2" gap at each end (for refinishing these pads)

  • Check timing - it is supposed to advanced, but given the dyno runs done vs. Brian Curry's bike - I suspect it isn't.

Done by 01/31/03

  • Installed a new version (actually a retro-mod done for me by Dave W) of the Fuel+. Apparently the Iron-Butt people (who love Dave's projects) wanted an average mileage indication that took into account the time from when the engine is first started during a 24 hour period, and the last time it is shut off. This average includes non-running time (for fuel stops, food breaks).
     This made it useless for checking on the Ev value (37.5MPH average speed = 1 Eilenvector). I liked the older design where it only averaged the speed during engine running interval. Dave made me up a new Fuel+ that did this like the older ones did.

  • Ordered new Braking rotors for the front. Nothing else I tried has worked. Will be installing them next week. (See below)

  • Sent tankbag to Bob Weis for a rework and custom modification. When I get it back, I'll post details on the modification.

  • The pad for the bars is ready to go on - but haven't had time to pull the tank to disconnect all the switches. Soon..

  • Bought a used Garmin GPS III+ and made a mount for it. See details here

Done by 02/16/03

  • Tankbag is back from Bob Weis - as usual, an excellent job. It was modified so I can fill the tank by flipping the bag back on the seat, instead of having it hang off a zipper to the side. Will post photos if it ever stops snowing (I hate snow! 3 weeks without a ride, and 1-2' of the stuff coming tonight) UPDATE - see link to right on the modification results.

  • Next week came - and ended with a snow-day, so what to do?
    I replaced the brake rotors with the Braking semi-floating rotors. After lots of tries to fix the old rotors (including several visits to local machinists who are at least willing to try) - I gave up and replaced them. See LINK here with Braking rotors. I also replaced the stock pads (almost new) with Braking pads - which seem to give a bit more 'bite' on initial use, and there is no more pulsing.

Update as of 04/18/03

  • Installed a Philips Vision-Plus headlight bulb. Had to order it from England since it isn't sold in the US. It is noticeably brighter than the stock bulb, but still rated at 55/60W. A big improvement in nighttime vision.

  • Replaced the entire wiring harness. The old harness has been damaged by a faulty electrical installation done by the past-owners mechanic. Although I repaired it at the time, on a K harness, without complete disassembly, you never can be certain you've found all the problems. I had noticed some odd electrical 'glitches' - making me not trust the old harness, so it got replaced.
    A used harness was found via a posting to the IBMWR list - cost was very reasonable compared to new. The work, from start to finish - including some Lily Gilding took about 16 hours. The new harness seems to work just fine.

  • New seat - a rebuilt Corbin seat is being made by Sargent. No extreme modifications, but hopefully it will be more comfortable than the Corbin on the bike now. (See below - it was MUCH MUCH WORSE) The current one has hardened up with age and makes itself known after about 3 hours of riding.

  • I've also purchased a set of fork-mount light brackets used from someone on the IBMWR list. These were made by Martin Fabrication, mount using the reflector/fender mounting bolts, and are made to take PIAA lights. With some quality time spent on the polishing wheel - they are fairly attractive. I'm going shopping for some PIAA clone lights to give them a try. Photos of the result can be seen here.

UPDATE - 09/10/03

  • As of right now - it has 52,000 some miles on it. Roughly 7,000 since I got it a year ago.

  • I have made a few more changes:

  • Before going to Charleston, I had Tim Bond (Bondo) straighten a slight wobble that was in the back rim. This wobble (about 1/8") was the cause of a hands-off wobble that started at about 50MPH and continued up to about 70MPH. Tim did a great job (highly recommended - and he is an IBMWR member and BMW rider.)
    Tim's website <- click here. Tim managed to work around an odd schedule I had (I was going to England for 2 weeks and sent the wheel the day before I left, and had it back at a friends shop to put new rubber on it - they day before I returned - NO downtime at all), plus his work was terrific and price was great.

  • I installed new Metzeler MZ4's on front and rear. Nice confidence inspiring tire - worked well in the rain going to Charleston, and never have given me any reason to regret buying them.

  • After riding about 800 miles total from NJ to Charleston WV and back - I decided the stock bars are a tad painful for me. So I swapped in a set of C bars. You can click on the photo on the right for how it looks.

  • At Charleston I had the pin-striping touched up. Looks great now.

  • I've added a LaminarLIP to the screen on the fairing to help with buffeting - a common S complaint. This appears to have totally solved the buffeting, plus reduces the noise level in my helmet greatly. More details can be found by click on THIS LINK or by clicking on the photo on the right. This was the "prototype" K75S lip, I sent them my old windshield - they sent it back with the LaminarLIP. Turnaround was less than a week!

    Update on the Laminar Lip - love it. It has smoothed the airflow that gets to my helmet so it doesn't buffet me, while still giving airflow to the face area so I'm not hot. It also makes the bike feel more stable at higher (for me - 80MPH indicated) speeds. Great improvement. It may or may not work as well on your K75S depending on your body height and riding position. While I'm short of leg - I'm not that short of body, and the position for me works just fine. I can feel turbulent flow just over the top of my helmet. As a bonus - it's quieter riding now - less noise from the Shuberth helmet.

UPDATE - 12/21/03

  • Installed a new BMW "Comfort" seat. The Corbin seat worked for me somewhat (good for about 3 hours before I was popping ibuprofen. The custom seat I had Sargent make for me didn't work at all (even after they tried 3 times), but I found the BMW "Comfort" seat does work, and isn't priced too badly if you get it from Hammersley BMW.  Cost was about $275 including shipping and it was brand new from Germany. So far - I'm very happy with the Comfort seat - it sits well and isn't as ugly as some other solutions, plus it fits like it was made for the bike (which it obviously was :-)

  • I'm also expecting for Christmas - a Garmin GPS-V, to replace the GPS III+. The increased memory will be welcome since then I should be able to download ALL of NJ to it :-) Since it's the same identical size as the GPS III+ no changes to the GPS mount will be necessary.

  • Cleaned the ignition switch - which cured an intermittent start problem I had.. Go here for details

2004 Spring

  • The brake shudder has returned. Damn. I tried having the Braking rotor disks Blanchard ground to fix it - but no dice - parallelism was a problem, and more important apparently than the surface finish.  I did determine that the problem is NOT warping, but surface friction variations.

    I finally did fix it with a set of used rotors (after trying 4 different used ones).. and measurements of all the rotors in question show them well within BMW's specifications..

    I suspect the cause was that after a winter ride this year - the bike was salty, so I washed it off in the driveway. When I next went to take it out - the pads were rusted to the rotors, requiring some force to break free. I think the rusted area - which even after cleaning up shows pitting is the cause of the shudder.

    From now on - I'll be taking the bike for a ride after washing it so the disks and pads are nice and dry before pushing it into the garage.

  • Changed the oil and decided to have an oil analysis done just for the heck of it. The results were good - and show that a K engine can easily go 6,000 miles on synthetic oil, and perhaps even further. The analysis results can be seen here (Adobe Acrobat required..)  The change was at 55,555 miles (I purposely waited for that mileage - figured it would be easy to remember. Once again - Mobil 1 was used.

UPDATE 12/05/2004


I've been too busy riding the bike to post my updates here. Sorry about that. (Not REALLY sorry..) But a few things have been done which are somewhat significant:


  • Front Suspension: As I may or may not have noted - when I got this bike I was really surprised at how little dive the front end had in it on braking. It was almost non-existent. It finally dawned on me that perhaps this was why my hands and arms would start to really hurt after a few hours in the saddle, especially on rough roads. The front suspension basically had no compliance.

I had asked the former owner if anything had been done to the front suspension, and he replied that he thought there had been, but he was unsure what it was. I finally decided I couldn't stand the beating I was taking and something HAD to be done about it.


As luck would have it - at the New Sweden BMW Last-Chance rally - Works Performance had given as door prizes gift certificates of $100 off on any purchase or service by Works, and I managed to win one. Since Works has fork-springs available for $109 - this seemed just idea. New fork springs were ordered for $9 and shipping cost. THANKS MUCH TO WORKS PERFORMANCE!


So - when the new springs arrived - I removed the top caps  off the forks and pulled out the springs that were in it. They were - to say the least - a very odd combination. At the top were two of the BMW ~4" long spacer tubes. Under these were a VERY stiff short spring with a not very stiff progressively wound spring under it.


I calculated out the total movement left after the two spacers were in place, and the caps in place - and it appeared the forks might have 2" of travel left - primarily from the very stiff short spring. This explained the lack of dive on braking.


The Works springs are also a dual spring setup, consisting of one short and SOFT spring, then one longer and stiffer spring. There are also three different length tubes that go inside the short/soft spring to set a "crossover" point from soft to stiffer. It also included a plastic spacer 1.75" long.


Long story short - I installed the new springs and new fork oil. I first used the shortest tube inside the short spring, but found this resulted in a bit too soft an initial response - it got replaced with the middle length crossover tube. I  also used a slightly shorter spacer 1.5" long since these  were going on a lighter bike (the springs are spec'd for an  RT, not an S.) Going to the middle length crossover tube  gave an EXCELLENT ride. No sharp impulse shocks to my hands and shoulders and a very nicely controlled ride. I did have to get used to some compression and dive under braking, but it took only a short while to get used to it. It's my belief the former owner saw a "hot-race-setup" for the springs and had it reproduced on the bike. What's hot on the track isn't necessarily what you want for everyday use. I'm quite happy with the suspension now.


  • BRAKE SHUDDER AGAIN! If you've been following - this is the third time I've experienced a very unnerving brake shudder on the front end of this bike. The other times, I solved this by replacing the rotors. The solution only seemed to last about 8,000 miles this time, and that was getting WAY too expensive.

I had email chats with a number of BMW wrenches. One - Tom Cutter of the Rubber Chicken Garage - told me that it took him a while to learn this lesson - but when you have repeated incidents of this sort of shudder, replace the front wheel bearings.


I took Tom at his word - and Brian Curry and I replaced the front wheel bearings. The old ones felt just fine when spinning the wheel. They felt just fine when removed from the hub/wheel. They had a very slight and hard to feel notch or hard spot when rotated on the wheel by hand (finger in the center of the bearing, wheel off the bike.) In this state - the bearings are preloaded by the spacer between the two bearings. Apparently when removed with no preload - the bearings feel just fine.


Again - long story short - the shudder is gone. I'm still using the same rotors that gave the shudder before. Tom was absolutely correct, and I thank him for the hint. I was attacking the symptom not the cause, although the cause was a bit obscure and hard to explain.


So - all is well again. The bike now has ~61,075 miles on it as of today, and is getting more and more enjoyable to ride.  Nice ride today - temps in the low 50's with bright sunshine. Doesn't get any better for December!

Update 11/13/2006.

The K75S is now for sale on the IBMWR marketplace. The reason for the sale is I bought an oilhead, and haven't been riding it. Rather than have it sit in the garage gathering dust - I'd like to see it on the road with a new owner.


Some people have asked what's happened since the last report on it in 2004.. Well - another 9,000 miles were put on it (it's now at 70,800+/-). In the spring of 2006 it got all fluids changed - including a complete brake fluid flush. It got a new battery. It got new front rotors from EBC and new pads from EBC. I believe the EBC rotors are the final solution to the recurrent problems with shudder I experienced. These rotors are made from steel, not stainless steel. They are full-floating rotors. The steel is supposed to have better resistance to corrosion and better heat transfer properties compared to the stainless steel. Surprisingly - they don't really seem to rust. The brakes are excellent now - good bite and no shudder.


What else was done? Ummm... new tank bag by RKA - better design for the K bike and very useable with a bigger map window.


The engine got a new output shaft mainseal and the clutch-basket O ring, did this right before a ride to Vermont for the MOA rally. The O ring had done what it does on all K bikes and dried up and started leaking (not bad for 20 years!), so while I had it apart, I also installed a new main-seal. The clutch disk looked just fine as did all the other clutch components, and all the splines were still in excellent condition.

What's on the K75S (as of 11/06):

  • Wider polished rims - 3 spoke 18" rims, fully polished, from a K100RS 4-valve.

  • Radial Tires - never offered on the K75 - these transform the handling. Currently has Metzler Z6 radials on it

  • Headlight modulator - Kissan headlight modulator. Besides helping to wake up brain-dead-cagers - it seems to deter deer just a bit. Much lower number of incidents of deer-jumps since this was installed. I won't ride a bike without it

  • ABS - not offered for the '87 K75 series - this was retrofitted by a former owner at quite a bit of expense

  • C-Bars - give a bit more relaxed riding position. The original S bars will come with the bike and can be refitted easily

  • Stainless fasteners - about every visible fastener on the bike has been replaced with polished stainless steel fasteners

  • Custom engine/frame polishing - see the pics for details.

  • Full bags - side bags, top-case, all keyed to the ignition. Also come with the liners for each.

  • Gerbing Heat-Controller Module - built in - this neatly and handily solves the too-much, too-little heat problem when using Gerbing heated clothing.

  • Eastern-Beaver Headlight Relays - a rather common problem with K bikes is failure of the high-low switch for the headlight. There can also be low voltage reaching the headlight due to the marginal wiring sizes BMW used - which reduces headlight output and life. The relay kit solves the problem, and is a neat - plug and play solution.

  • Osram Silverstar Headlight bulb - which actually (by measurement) offers 50% more light than the standard H4 bulb, and the same lifetime as a standard bulb while drawing the same wattage.

  • PIAA clone lights - mounted on the fork sliders these provide excellent fill-in lighting, plus make the bike more visible to cars

  • Garmin GPS mount - currently setup for the Garmin Quest (or Quest-2) - this custom mount is easily adaptable to lots of different Garmin models, and the BMW - Navigator II or III. It's designed to require minimum eye movement to view the GPS, an important safety factor.

  • BMW fuel level and coolant temp gauges - never standard on the S - these neatly integrate into the stock fairing and look stock. The wiring harness for them is also stock.

  • EBC full-floating rotors and EBC pads - on the front. Good feel, excellent bite and no shudder.

  • Laminar Lip - moves the wind envelope up about 2 inches.

  • BMW Comfort seat - actually is comfortable.

  • Suspension - the best Wilbers available for the rear, with the adjustable length option, hydraulic preload adjuster, adjustable high-low speed compression damping, adjustable rebound damping, remote oil reservoir. The front forks have the sport forks, with Works-Performance springs and BMW 7W fork oil.

  • Fuel-Plus - on-board computer system, gives miles remaining, daily mileage, average speed, average MPG and lots more. Now out of production - rare and valuable addition to a K bike.

  • 700W alternator - off later K bike. Provides ample power for lots of lights, heated clothing and whatever else you want to power off the bike.

  • CC Products Fuel-Injector cover - this area looks 'unfinished' on a stock K bike. The CC products cover both gives a finished appearance and protection to the fuel-injectors and wiring.

  • Heated Grips and R1150 grips - optional BMW heated grips were added - and later model R1150 handgrips replaced the square grips BMW used on the K75. If you want them - the square ones are still kicking around somewhere.

  • Run-n-Lites - on all 4 turnsignals and brake light

  • Light-blazer - tail light enhancement - frame for the plate with a modulated LED brake-light cluster under it.

  • And probably a lot more I've forgotten..


Dsc00021.jpg (100746 bytes) Left side view
Dsc00022.jpg (118142 bytes) Right Rear Quarter View
Fuel Gauge and HeatTroller Custom install (other side has temp gauge) Fuel Gauge and HeatTroller control
Polished ribs and "BMW" and all stainless fasteners - polished Engine crankcase, polished ribs and BMW logo, custom stainless cover bolts
Polished ribs and center emblem, and all stainless fasteners - polished Valve cover, polished ribs and spark plug cover BMW logo polished, custom stainless cover bolts
Alternating polished ribs on footpeg mounts, and all stainless fasteners - polished Footpeg mount, polished hash marks
Alternating polished ribs on footpeg mount, and all stainless fasteners - polished Footpeg mount, polished hash marks
Cloistome emblems all around Cloisonné emblems
Reflective sheets - no light Bags with reflective panels - no light on them
Reflective sheets - flash illuminated Bags with reflective panels - lit from flash



K75 Dyno Runs  Dyno Runs

Click here for Garmin mount details

Garmin III+ mounting details

Tankbag modification by Bob Weis.
Bob converted the original Multivaro bag - which had two zippers about 8" long on each side to a design much like the later models. The reason I wanted this was to make it easier to fuel up. With the later design - you can just pull both side zippers towards the rear of the bag and flip it backwards on the seat. Works great!
Knock-off PIAA lights
C Bars
LaminarLIP Click for more information
BMW Comfort Seat Installed