Now for something completely different....BMWK75s

[sdcr]

It might be the 3 feet of snow covering everything in sight, but I have been over perusing motorcycle classified ads in the last week. I'm specifically looking at the later K75  models.

What are your experiences with these bikes?

Any Achilles heal issues to look for? 

any preferred years or models?

never had a K bike,  so I'm all ears.

thanks.

John

83 Le Mans III

[Perazzimx14]

Only weak link I am aware of is if previous owners did not lube drive line splines. Splines must be lubed at recommended intervals. Other than that they are silky smooth and run forever.

It is also typical for them to smoke wildly upon startup after being on the side stand. This is nothing to work about and is considered normal.

There is currently a nice K75 f/s in Gettysburg PA. If its something you are interested in I can go get some eyes on it for you. I could also persuade a buddy who has had a K75 for the last 20 years to ride along.

http://harrisburg.craigslist.org/mcy/5416592520.html

[Murray]

Highly complicated bike (mainly the electrical system) thats well over 20 plus years old and parts support is a little variable.

[Scud]

I just got a 1992 K75s that needed a little TLC and a 1990 K75s that was basically done (at 180,000 miles) as a parts bike - merging them into one bike. The little brick is running really well - starts easy, predictable - nice luggage. And the whole bike (with luggage) cost me less than a set of new hard bags and mounts for a V11. It's my commuter/errand runner/airport bike (it's at an airport now, while I'm in Chicago).

Like any bike, look for maintenance history - or buy cheap and take your chances (which is what I did).

Something about the front brake rotors can causes pulsing if the bike sits - the pads sort of weld to the rotors. But aftermarket rotors and pads are readily available - I have a set waiting to put on.

I think the K75s is becoming collectible - if you care about that.

They made a lot of improvements over the production cycle - so later ones will have a few more features and potentially fewer bugs. The major, easy-to-spot difference is the wheels. Early model wheels have 4 Y-spokes (8 contact points to rim). Later models have smoother-looking 3=spoke wheels. Interestingly, the Y-spokes are both lighter and stronger - so I put the old rims on the new bike (I think they look better too, but that's subjective).

No problems with parts so far. The motobrick forum is helpful - there are quite a few Guzzi owners over there too. I think the Ks are quirky enough to appeal to us Guzzisti.

[screamday]

http://harrisburg.craigslist.org/mcy/5416592520.html

Wow.....that's pretty sweet. I always wanted one of those. Too bad I'm a little cash poor at the moment. 

[steven c]

 When I had my K75s I changed out the bars with those from a K75c. Thhe stock bars are low and stubby. It came with a corbin seat which was very nice. Very pleasant bike and for the day pretty exotic with the Aluminum gas tank ( some do corrode from the inside ) single sided swing arm, fuel injection. Sometimes I wonder why I sold it.

[stick]

K75 engines are much smoother than the K100's.  I drove an '86 K100 and it reminded me of a KZ1000.  Same sounds, and vibes up thru the seat + pegs.  K75S that I tried had a much more inspiring sound, also.

[sdcr]

Highly complicated bike (mainly the electrical system) thats well over 20 plus years old and parts support is a little variable.

Murray,

Would you please expound on the complicated comment, and specifically about the  electrical system problems? I've not heard that before.

Thanks.

John

83 Le Mans III

[clubman]

Murray,

Would you please expound on the complicated comment, and specifically about the  electrical system problems? I've not heard that before.

Thanks.

John

83 Le Mans III

I bought one new in 1991 and rode it for 19 yrs./99K miles so have some experience. The electrical system is no more complicated than any modern bike. Some extra circuitry if it is an ABS model. Most problems in a bike of this age come from corrosion in the plug in connectors throughout the wire loom. Good idea to unplug clean and lubricate all of them, especially the relays located in a box under the tank. Some of the rubber parts inside the tank (rubber socket for fuel pump, fuel lines ) will be deteriorated if gasohol has been used but are replaceable. Still get most new parts thru BMW dealer, but $$. Lots of stuff on fleabay. I've bought and sold a lot of BMW parts for various BMW's thru the Internet BMW Riders site (IBMWR). They also have an excellent problem solving section written by some of the best techs around, will solve most any problem you can think of. Only major failure I had was the output seal on transmission.

[Lcarlson]

The first bike I ever bought new was a K75/3. It was very smooth with a linear powerband, almost like a turbine in engine feel. The transmission was a little notchy, resulting in occasional missed shifts, but it otherwise performed flawlessly. Aesthetically, if ever there was a motorcycle that sounded like a sewing machine, this was it. I sold it after three years to get an R1100R, to get the traditional boxer motor and the Telelever front suspension (an excellent feature on a streetbike.) And more power, of course.

[ohiorider]

I put a bunch of miles on K bikes over 15 years.
1985 K100RS - traded at 65,000 miles.  No issues
1988 K75S     - traded at 10,000 miles to go back to K100RS.  I'd gotten used to the roughness of the 100 and liked the power.
1989 K100RS - traded on K1100LT at 43,000 miles .  No issues (one speedo replaced under warranty)
1993 K1100LT - traded at 7500 miles.  Did not like the full fairing K bike, except on cool days
1993 K1100RS - traded after dealer 'repaired' front suspension (huge pot hole impact) at 15,000 miles.  Was not right afterwards.
1999 K1200RS - Sold at 42,000 miles.  had to have clutch slave cylinder replaced under warranty.

My K experience.  Weak link on early K100 models was the MotoMeter speedometer.  My 1985 fortunately worked from day 1 until I traded the bike 5 years later.  The early K bikes used a 'flapper' in the throttle body that measured (I think) mass air flow) and permitted installation of a wide variety of aftermarket pipes with no change in mapping.  Later models switched to a newer Bosch system.  Think the early may have been K Jetronic, later was LE jetronic, ultimately switched to Motronic, that combined electronic ignition and fuel injection control in a single box.  I'm probably wrong on model designation.

The K75S probably had the best telescopic suspension of any of the earlier K bikes, and was ultimately used on later K100 models as well.  However, the K75, as I recall, was never equipped with the single side Paralever swingarm, but soldiered on with the single side Monolever until production ceased.

Though the 75 and 100 models spun the clutch in the opposite direction of the crank, thus eliminating some of the sideways torque effect, only the 75 triples had balance weights installed on the shaft that supported the clutch.  This engine, as others have said, was extremely smooth, and also had that unique triple sound, somewhat like modern day Triumph triples.

Although the early K bikes were never the huge success BMW had anticipated, they still sold enough of them in the USA over the years that there is a large stock of used parts available.  Google "bmw k bike parts" and check it out.

The first K75 was rated at 75hp, later models at 70hp.  Same reduction happened to the K100.  My 85 was rated at 90hp, my 89 at 82hp.  75 models used the same tranny gearing, but had a lower final drive ratio.  As I recall, my K100 showed approx. 3700rpm at 60mph.  The K75S was closer to 4200-4400rpm at 60mph.  Redline on both is at 8750rpm.

Aside from small mods to the frame, the 75 and 100 bikes are about the same physical size.  Since BMW essentially loped a cylinder off the four to make the three, the frame tubes that tie to the front of the engine are angled back at more of an angle.  The engine is a stressed frame member.

Perhaps taking some of the weight off the front suspension resulted in BMW installing a somewhat crude affair in the 75 series ..... a pad of rubber-like material inside the steering head that exerted some friction on the steering shaft.  I think it was called a "Monoblock."

ABS - the first K bike with ABS (K100RS/ABS) was the 1988 model.  At some later date, all K bikes sold in the USA came with ABS, including the K75 models.  If the ABS failed, brake action remained the same, just no ABS.

I would think the bulk of any electrical issues may be a result of the age of many of these bikes, and the subsequent corrosion of many of the connectors.  That would be a big deal for me, since I'm electrically-challenged.

As mentioned in this thread, BMW called for pulling the tranny periodically and lubing the clutch splines.  I think there is a method of unbolting and slightly moving the tranny rearward, and applying grease thru the space between bell housing and tranny. 

I believe the final K75 models sold in the US were 1995 models.  K75's sold fairly well in the USA and Spain, less so in other European countries, I recall reading in one of the club mags of the time.

[Shorty]

I had 2 of them, a 93 and a 95. Smooth. NOT the Sport model. Quiet. TALL.  Ponderous for my 30 inch inseam in garage or low speed. Once rolling, a good handler. Problems? The one I bought new had the starter sprag replaced under warranty. The second one, used, needed a crankcase vent hose. Oh, and a battery. In my opinion, one of the best bikes, ever. Single sided swing arm, remove the rear wheel like a car. Aluminum fuel tank. Stainless steel exhaust. Well sorted fuel injection. Self retracting sidestand.(works with clutch lever) A little retractable handle to help lift it up on the centerstand. Decent tool kit. You can change front wheel by using centerstand. Enough electrical power to do heated clothes, aux lights.   The bike makes a little George Jetson whine that some find to be unmanly. Ride with the Guzzi gang, you'll never hear it. 

[Roebling3]

I had a '93 K75S from new. Early models had electrical problems within the instrument pod. Most all models, if stored and /or ridden in hot climates had problems with the Hall sensor. Not specifically the sensor but rather the poorly chosen grade / type of wire used. An easy fix if you learn quickly. As mentioned previously the so-called steering dampener is a mean joke. It was of little good as new and cannot be repaired. Apparently the viscosity of the trapped damping fluid cannot be duplicated. @ least a few 'gurus' have tried. I had a few tank slappers when the front went light on down hill curves. They are IMO rather top heavy.

The clutch splines are critical. W/abs and a lift it took ~8 to 10 hours to pull and re-install. The splines are on the trans, mainshaft. Once the female splines on the disc begin to wear it all worsens over time and miles. I put 7 clutch discs in mine. About one every other tire change. bmw said there was nothing wrong and it was normal wear.

A minor problem? I had fully loaded factory bags, locked on the carriers. Both bags hopped off on an interstate, at speed. not a pretty sight. R3~

[ohiorider]

I had a '93 K75S from new. Early models had electrical problems within the instrument pod. Most all models, if stored and /or ridden in hot climates had problems with the Hall sensor. Not specifically the sensor but rather the poorly chosen grade / type of wire used. An easy fix if you learn quickly. As mentioned previously the so-called steering dampener is a mean joke. It was of little good as new and cannot be repaired. Apparently the viscosity of the trapped damping fluid cannot be duplicated. @ least a few 'gurus' have tried. I had a few tank slappers when the front went light on down hill curves. They are IMO rather The clutch splines are critical. W/abs and a lift it took ~8 to 10 hours to pull and re-install. The splines are on the trans, mainshaft. Once the female splines on the disc begin to wear it all worsens over time and miles. I put 7 clutch discs in mine. About one every other tire change. bmw said there was nothing wrong and it was normal wear.
top heavy.


A minor problem? I had fully loaded factory bags, locked on the carriers. Both bags hopped off on an interstate, at speed. not a pretty sight. R3~

Roebling, I'm guessing, based on the tires at the time, you were replacing them every 6-7k miles, and having to replace clutch plate at 12-14k miles.  I personally had zero clutch issues with any of my K bikes, including the 1985 K100RS when I traded at 65k miles.

Having said that, I recall a riding buddy of mine from work, who had always ridden "big Red" bikes, deciding to purchase a beautiful low mileage K75S.  After about one riding season, he was pulling away from a stop sign, when suddenly, nothing.  As though the bike was in neutral.  The clutch splines had gone out.  In his case, it was the splines on the input shaft.

We found out/heard it thru the grapevine/someplace ....... that some of the bell housings or front flanges on the trannys, were machined incorrectly, causing the input shaft to be misaligned with the clutch plate splines, causing this failure.  Sounds like yours may have had a similar issue, since you were experiencing way too many spline failures.

EDIT:  Here's a link to an old ADV Rider thread describing your experience with clutch failure.
http://advrider.com/index.php?threads/k75-splines.363215/

Bob

[Roebling3]

Thanx for writing, ohiorider.  I've believed the poor matchup between engine and transmission to be the problem from day one.  A well known bmw guy said that K75S's were shipped crated but w/out a support block under the engine/trans., because of the belly pan. If the crate/bike were dropped too hard there would be damage. In 93 they used some useless lube at the factory on the main shaft splines. I believe it was called Optimal. It was white like Luberiplate and flew off readily. A very poor choice, but cheap compared to that clear red stuff I used for years on airheads.
I neglected to mention the costs of replacing the Abs pumps and ECU. Aftermarket may being doing some good by now. 
I won't even ride a bmw again. I cannot abide arrogance in any form.  Thanx again. Kind of you to respond. R3~ 

[cookiemech]

I have two of them, a 1994 K75RT and a 1995 K75. Can't add much to what others have said, other than I believe these bikes (specifically, K75 variants, not K100 ones) are the toughest, best-engineered bikes BMW ever built or ever will. They are underpowered and overdesigned, and as mentioned above, spline lubes are important.

I rode my RT to work for 11 winters in awful conditions. Never did it let me down or try to put me in a ditch. Solid gold, to me.

[sdcr]

Hey,  I feel like I just attended K75 class.

 Thanks for all the info and details. The one that perazzimix put the CL link on is the one that started my search. I'm going to try to see it this weekend.


John

83 Le Mans III

[wavedog]

I was a happy K-75 owner for a couple of years. I bought a 1987 K-75 with a scout parabellum fairing and a tall windscreen and BMW bags. It had one of those ridiculous corbin seats. Ugly, rock hard. Prior to my purchasing it, the bike had been gone thru by a local BMW guru in Lubbock, TX. What a great bike. Once I threw the corbin in the trash can and got a good seat I enjoyed every mile. In the first 3 months that I owned it I put on 18,000 miles. It had 28K miles when I got it and 80K miles when I sold it a couple years later. I rode that thing all over the west. It sounded like George Jetsons flying car. I learned to love the tweet. Solid, reliable, good gas mileage, run at any speed all day long. Never had a problem. I really enjoyed that bike. The engine, compared to my VFR, was turbine smooth. I cant tell you anything technical to look for or how to maintain one. I took mine to a mechanic for a valve adjustment and did the rest myself but there was very little to do. Oil/fluid changes, filters, plugs, tires, brakes, spline lube whoop de doo. I guess I was lucky and got a good one. If you get one I hope that you end up with a good one and ride the heck out of it.

[rbm]

Have owned both a K100 and a K75.  Currently own a 1987 K75 with 55000km.  BMW enthusiasts will tell you at that kilomerage, it's just begun to be broken in.  Can't add to anything that hasn't already been said about the virtues and failings of the K-bikes.  They are like appliances - just fill with gas and change the oil occasionally.  Very little maintenance needed.  Support from owners is excellent and freely offered. Also, check out Specialks.net to see how customizable these steeds are, my blog in my signature to see my K75, and read some of the forums motobrick.com and k100-forum.com.

The clutch splines are critical. W/abs and a lift it took ~8 to 10 hours to pull and re-install. The splines are on the trans, mainshaft. Once the female splines on the disc begin to wear it all worsens over time and miles. I put 7 clutch discs in mine. About one every other tire change. bmw said there was nothing wrong and it was normal wear.

This clutch spline wear is indicative of misalignment in the bellhousing.  The dealer was wrong; there was apparently a batch of castings which had improper machining such that the alignment of the transmission with the output shaft was off, causing excessive clutch spline wear.  They should have replaced the bellhousing to correct the problem, not continuously replace the clutch.

[LBC Tenni]

I have a 1990 K75 that I de-uglified with some simple mods. I replaced the big glitchy moto meter gauges with a nice little compact dash called Trail-tech vapor. I swapped the heavy and silent exhaust with a Staintune. Now it sounds like a motorcycle. I've never had any electrical trouble at all. It's a fantastic machine when you're in the mood for smooooth. You can pick up a clean low mile specimen in the US for about $2k if you're patient. Then you have a fun little project to putter with and a very rewarding result. Shines in the twisties too. 

[lucky phil]

It might be the 3 feet of snow covering everything in sight, but I have been over perusing motorcycle classified ads in the last week. I'm specifically looking at the later K75  models.

What are your experiences with these bikes?

Any Achilles heal issues to look for? 

any preferred years or models?

never had a K bike,  so I'm all ears.

thanks.

John

83 Le Mans III

I've owned 2 old K100's plus dozens of other bikes. I rode a K75 over a weekend years ago and it had the worst throttle response I've ever experienced. Nothing wrong with the particular bike just the old K jetronic injection system in combination with a triple power plant meant pathetic throttle response especially when blipping for down shifts.
Basically an under powered slow to rev old bus. Stay away.
Ciao

[LBC Tenni]

To each his own. I have no complaint about the throttle response on mine. The power to weight improves considerably when you chop off the long and extremely heavy tail/trunk. Stock exhaust is a boat anchor as well. It takes a little simple work, but they can be transformed into something quite nice, with very little investment.

[sdcr]

I have a 1990 K75 that I de-uglified with some simple mods. I replaced the big glitchy moto meter gauges with a nice little compact dash called Trail-tech vapor. I swapped the heavy and silent exhaust with a Staintune. Now it sounds like a motorcycle. I've never had any electrical trouble at all. It's a fantastic machine when you're in the mood for smooooth. You can pick up a clean low mile specimen in the US for about $2k if you're patient. Then you have a fun little project to putter with and a very rewarding result. Shines in the twisties too. 

Although my personal preference is for original machines, I really like what you did to that K75! It's a different take on the cafe bike. Very nice!


John

Le Mans III

[Perazzimx14]

Are you going to look at the brick this weekend?

If your going to be in the area I'm about 25 minutes from Gettysburg if you want to stop buy chew the fat and have a cold refreshment

[sdcr]

Are you going to look at the brick this weekend?

If your going to be in the area I'm about 25 minutes from Gettysburg if you want to stop buy chew the fat and have a cold refreshment

Sent you a pm.

John

[OlderSlower]

I had a K75S and a K75RT.  Both were fine bikes, very smooth and appliance like.  They are an acquired taste. IMHO they do everything well and nothing great.  Did I mention that they are slow?  I had some charging issues and fuel and air hose issues, but nothing dramatic. 

[MRLost]

I had a 1994 K75s with ABS for 11 years. If my legs were three inches longer, I would still own that bike. Lots of good info in the previous replies.

Super smooth motor - like an electric train - and a much better handling suspension than one might expect. You just needed to keep the revs up for power (not a problem for the K75 motor) and stay very deliberate in the corners. I put Progressive springs in the forks, which helped a lot, and an Ohlins shock unit in back and never thought about the suspension again.

Engine is so trouble free that numerous countries used the K75 for their national police: Spain, South Africa, Argentina (I believe), and others. Police like that put millions of miles on their machines and are very focused on cost of ownership and maintenance. I once had a certified and highly experienced BMW mechanic tell me it was the best motor BMW ever built - absolutely bullet-proof. He'd seen a number of K-bikes with more than 200,000 miles.

Worlds heaviest 750. About 530 pounds with no gas. But rock solid on the highway. A great bike for long, long rides on the super slab. If it falls over in a parking lot, you will know you're a man if you can pick it up by yourself.

First bike BMW built with electronic instruments so they used the same company that built instruments for their cars. Problem was they weren't weather proof so they died under warranty and it cost BMW a fortune to replace them. Never trust the milage shown on an older K-bike.

Type-1 ABS so that can be a problem. If the ABS fails, you usually have to replace the entire board and I bet those are hard to get. However, if the ABS is out, then the brakes work just like ordinary brakes. I never had any problems or issues with my brakes but I did have the entire brake system flushed and tested every year.

Overall, a great bike if your legs are long enough.

[Daleroso]

Had 3 over 25 yrs. Simply put; Not 1 problem. Smoothest engine BMW ever made (the R80 was the smoothest airhead). Their current 6 is smooth also. Smoking ended when they addressed the rings but was never a reliability problem. Just the occasional shot from friends. Ease the tranny back a bit & lube the spline with a greased tooth brush taped to an extension every 10 12K. Just about any aftermarket suspension change improves any OEM system on any bike. Cost as much to make as the K100 was a sales issue for BMW because of the skewed perception Americans have that bigger is better. . Slow? Fast? Which is which & according to who? Many have gone 200-300K+. If there's a category of perfect motorcycles that if someone owned & wished they hadn't sold, the BMW K75 would be one.

[Daleroso]

PS; there's an at home fix for the early K Motometer speedos. I've done 3.

[rbm]

Many of the parts on the K75 are interchangeable with the other classic K's -- K100, K1, K1100 and even the early K1200.  You can exchange the K1100 tranny and drivetrain to improve rear end handling performance, swap in K1100 forks and triple tree for improved frontend handling, exchange rims for wider radial tires, exchange throttle bodies from the K1100 for improved fueling.  It is a very versatile motorcycle for customizing.