Flying brick BMW thoughts?

I've always had a fondness for the flying brick K series BMW motorcycles of the '80's and '90's.   These use the horizontal acting inline 3 or 4 cylinder.   Have any of you had experience with these bikes and what are your thoughts/experiences on riding, service, parts availability, etc.?

Thanks!

I've owned quite a few of them - K75S, K100RS 16V and several K1100LTs.

I like them, but especially the early ones are getting a bit long in tooth. They're much higher tech than the airheads, and haven't necessarily all been maintained as they should have. As a relatively cheap tourer, a K1100LT is hard to beat. Probably the best weather protection that BMW ever put on a reasonably sized motorcyle.

They don't have a lot of problem areas, but the ones that tend to creep up are either expensive to fix, lots of work or both. Typical issues are:

• Gearbox input shaft splines worn because they haven't been lubricated regularly. That's not uncommon and while fixable, requires a new input shaft (plus taking the gearbox apart) or a good used transmission. Had that happen on one of my K1100s and once the splines give, you lose all drive. Not good at 70mph on the highway.
• Brake system issues - all K1100s and a large majority of the earlier bikes have ABS. The ABS actually works pretty well especially for the bikes' age, but requires regular brake fluid changes and the control unit can seize up as a result. The brakes usually still work OK, but I like having working ABS. A lot of people remove the whole ABS system once it decided to stop working, but I wouldn't pay good money for one that had it removed. There are enough out there that still have working ABS.
• Front brake calipers seize from lack of use. They're four piston calipers (Brembo, IIRC) and most parts places in the US won't sell you the repair kit. Motorworks in the UK will however and they do ship to the US.
• On the K1100LT, the electric windscreen is often inoperable. You want it operable. Same goes for the heated grips.
• Other than that, mostly typical old bike problems with damage from standing and/or aging rubber and plastic.

Would I get another one? Well, maybe. I wouldn't turn down a nice K1, and a good K1100LT makes a good budget tourer, but they're not that easy to find. They are more DIY friendly than the later models and a lot of people think the quality is better, too.

Avoid K75RTs - the K75 motor is smoother than the four-banger K100/K1100, but it doesn't have enough oomph for the barn door of a fairing that bike carriers. In fact for a K75, I'd go look for a K75S.

Also, as a motorcycle journalist friend of mine keeps repeating, one doesn't buy BMW bike that don't come with hard bags. The bags are keyed to the bike usually, so you want the ones that the bike originally came with.

Oh, another tip for haggling - if you have a bike that should have working ABS but the ABS warning light is still flashing at you once you started it and rode it (you have to get it moving for the computer to pick up the wheel sensor readings), there is a good chance that it's an issue with the battery and not with the ABS. The ABS unit on these things hates low voltage, and low is even when the bike starts perfectly well.

So a potentlal multi-thousand-dollar repair can often be fixed with a new battery and a trickle charger.

With proper maintenance these things can cover huge mileages - I've owned a couple that had 50k+ miles on them, and a K75 with 120k miles.

I had a base k75 for a year I had as my 2 up bike for the lady. Eminently reliable and dull, but great values used at the moment I think. I see them all day long at 1500-2000$ Motors will run to 100k+ all day long, mine was non ABS.  I found some generic cafe style slip on that it made sound a million times better. Stock, the fuel pump is the loudest thing, and the exhaust note is Hoover vacuum at best. Huge oil capacity and dry automotive clutch so oil change intervals are car long. As stated, check and lube the splines. Mine had a dodgy fuel level sender which is also the power pass through for the pump, and they're getting awfully scarce, new is $200+ now I believe.  Some interesting customs coming out across the pond. I ultimately sold mine because I was spending way more time on it then my fun bikes because my wife ended up digging riding 2 up more then she had in almost a decade, and it just wasn't "cool" and I'm a hipster. 

I had a K-100rs for a few years.  With a K&N air filter and a SuperTrapp pipe, it scurried right along!  I put "bar backs" on, they moved the handlebars up and back about an inch, and recovered the seat by Sargent.  VERY good commuter, excellent for blistering through the mountains and wasn't hard to look at.  If I had a complaint, it would be the center stand is too long - hard to lift the bike up over center.

I sold it for what I aid for it, bought an R-1150rt.  If I wanted another brick I would probably get a K-75s. in RED.

I'm pretty happy with my R-90s clone.  SWMBO says I can have as many bikes as I want, but can't ever sell the R-90.  I don't ask ......

Had a 85 K100. A lot of parts are 85 model specific only. Can't add a lot that others haven't already added. 

But I found out the hard way, it didn't tolerate ethanol laced fuel. First time i fuelled up after getting it, I bought from a mixed fuel pump. Started out fine, but the bike started acting like it was vapor locking. No other issues. Managed to get some ethanol free 91 and eventually it cleared up. 

Thanks for the input everybody!   I'm trying to convince wife I NEED another bike.   She's not having it yet.  

I found a late K100 that's got all records and about 50k on her.  Splines maintained but water pump leaking.  Has hard cases and has had regular riding.  Looks great.   Priced OK.   I'm a relatively new rider and a big fellow at 6'3" and 275.   The HD bobber I inherited from my Uncle is awesome for a short ride but I want to take some longer trips now and it doesn't work for that at all.   

In reply to wawazat :

As mentioned, I've had a bunch of them but I've not had a water/oil pump issue with any of them. A quick poke around the k100.biz FAQ makes this out as a fairly simple to fix issue, but there is something ominous in there about "new parts" and "your dealer might not be able to get you the old parts". I suspect that this may mean you'll have to replace the whole water/oil pump assembly.

Which K100 model is it and how much is the seller asking for it?

I was wondering about the parts situation on these bikes.  Seller has pump parts that go with the bike.  
 

It WAS a 1992 K100 RS 16 valve.  Sold today.  Oh well.

Generally the parts situation is pretty good still. You might not be able to source everything from a BMW dealer but I've never had an issue finding parts.

A K100RS 16V is a nice bike, feels a little buzzier than the 8V versions though.