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Going to look at a K12RS - any pointers?


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I found an '01 K12RS that caught my eye. I'm supposed to go take a look at it tomorrow. (Sunday)

Any insight, pointers, or common issues that I should keep in mind? I had the RT for a while, but I expect that a K bike will have its own idiosyncrasies...



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How many miles?


Maintenance is the name of the game with a flying brick.


Brake fluid change?


Air filter? (often not done because reaching it is a pita -- have to remove the fairing and the fuel tank)


Fuel filter? (same access issues)


Air filter BMW or K&N? I usually walk away from K&N bikes.


Clutch fluid? (if no, of more that 30-40k miles, has the hydraulic slave cylinder been replaced?)


Coolant replaced? What color? Green is wrong/bad. Check the translucent coolant overflow bottle (on a K12LT it's under the left side of the driver seat; I'm not sure about the K12RS location).


When starting, any signs of the starter sprag clutch not engaging? (if the starter engagement clutch gets gummed up (a problem made worse by lack of regular oil changes) then the starter motor won't turn over the engine. Choices then are split the bike in half to get to the sprag clutch (forward side of the intermediate flange) or run one of the crud-cutting concoctions through the oil in hopes of diluting/removing the gunk in the sprag clutch. Keep in mind this is a rare problem, but if the starting doesn't sound perfectly normal, be aware of the possibility).


Valve clearances checked? (brick valves are very stable, but they do need to be checked)


If the bike at 100k miles, have the timing chain rails been checked or replaced? (the BMW rail spec is low (36K? 50K?), but experience showed that these rarely evidenced any significant wear at such low miles, but if you are up in the 100k range they should be eye-balled -- this is an interference engine, and breaking a guide and jumping cam gear teeth can lead to not-pretty results; again don't fret over this -- I can count the number of flying brick guide issues of which I'm aware eon one finger)


It is quite common for K12's to have grime on the front, driver's left side of the engine, typically from the seals around the timing chain cover or valve cover -- do not let that put you off.


This can be hard to check if you don't know where too look, but if you see any grime toward the driver's left rear of the engine, use a strong flashlight to peer straight down the heart of the bike over the top of the Telelever arm -- between the top of the engine and the (massive) frame backbone is a ~1" OD hose that leads from the port at the top rear of the engine to the left to the intakes. This is the crankcase ventilation hose. These hoses are well known to dry out and crack and make a mess on the rear of the engine, usually on the left. This is an annoyment, not a serious problem, but it takes a fair amount of work to get to it to replace -- discount negotiating material if that issue is present.


Is the idle steady, or does it hunt up/down a couple hundred rpm? (hunting is an indication of a vacuum leak, typically one of the vacuum nipples on the throttle bodies losing its cap or hose).


Other than that, the usual stuff -- throttle cable condition, shifting (the K12 trannies are a strong point -- pretty bullet proof), leaking shocks, crash damage, etc.



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If it has a coolant of coolant flushes being done, nothing major in the future unit possibly 100k miles. (Driveshaft)

If the owner has owned the bike for a number of years and has no idea what a coolant flush is, move on.

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'02 is when the changes were made.

Integrating turn signals/fairing/adjustable bars/pegs.

Biggest issue on K bike forums for these is the ABS module.

Some are repairable by Module Masters for reasonable $, some not.

Otherwise BMW version is $$$

So far, my '03 GT isn't covered by MM but earlier are (not sure if yours falls into yes group)


Will sound like a box of gravel when you start it up, TADT.


0-100-0 is impressive esp. for their age


ECU discussions on K bike forum interesting, major dif is some cold start stumble and gas mpg.

Many of us are mid upper 30's

with the better ECU 40's

this site has plenty of info and sticky's


love my brick, 35 years of boxers before


It is a long wheelbase/big bike

you have to work in technical stuff, I tend to just mosey along

but on sweepers/open roads/etc :Cool::thumbsup:

you can move them, when the model first came out in '98 a friend did the pre internet 55mph Deal's Gap run in 10 min and change

Which color scheme?

Crank it and ride it, you may really like it.

Best wishes.

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Dennis Andress

Most likely rubber hoses and seals will have deteriorated. The kind of stuff you could make a good winter's project out of,..


Open up the rubber boot between the swingarm and final driver to check for oil in the swingam. Just peel the boot back a little bit and wipe your finger inside to check. Oil in the swingarm will attack the rubber isolator in the driveshaft.


Stuff I posted long ago...

New plug wires are always a good thing, except for the price.


Find the crankcase vent hose. It should be just aft and slightly inboard of the #4 throttle body. It's a short and crocked hose that leads from the engine to the airbox. They are notorious for tearing and sucking air.


Open and clean every electrical connector under the tank. The injection system works with very low voltages and even a small resistance drop will change it's performance.


Remove, clean, and replace the throttle bodies. While at it, remove and reseal (new o'rings) the little intake tubes that lead from the throttle bodies to the head. There's an O'Ring under there that can also suck air. Same for the intake tubes. Inspect them for cracks and tears. Replace as needed. Be aware that spraying carb cleaner into the #4 throttle body will cause gunk to flow into the Throttle Position Sensor, which is attached to the end of the throttle shaft. You should remove the TPS first. Search "K Bikes" for my name and the word "throttle" and one of the results describes how to set the TPS Don't turn the idle stop screw or any of the synch adjusters between each throttle body. If you take the TPS off, cleaning it with a good contact cleaner is okay. (Test first to make sure the cleaner doesn't dissolve the plastic of the TPS.)


Does the fuel pump turn? A little bit of water in the fuel can cause them to freeze. Testing fuel pressure with a guage would be a good idea.

The ignition switch on both my 91 and 02 KRS was a dirt magnet. Every couple of years it would cause all sorts of electrical snafus

Is the TPS adjusted correctly? Slowly open the throttle and listen for a click from the TPS. It should happen as soon as the throttle comes off idle. Using the"choke" lever is a good way to test this.

Any vacuum leaks? Cracked intake stubs, the O'Rings between the intake and the head, vacuum hoses are all good places to check.

Spark plug wires. At $50+ they're way overpriced, but I used to replace mine every two or three years as they age poorly.



TPS Adjustment and more...


Post any questions...

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The only K-bike I've ever owned was a K1100LT so my experience with them is limited. However, I remember that the engine heat made the bike extremely uncomfortable in summer, at least here in north Georgia. I think the K1100s were particularly known for that but I would be sure to check out the engine heat on any K bike I was considering.

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Rats - my appointment to see it got canceled/rescheduled.


Thanks all for the tips. If it comes home I'll let ya know!

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Always liked that color combination.


Had a red 98 that I regret selling.


That looks like a good bike at a nice price!



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tom collins

i bought a very low mileage one 3 summers ago. 2003 with 8k miles. about the middle of summer 2004 with 14-15k miles, the clutch started to slip a little. still using it with a little slip, the rear main seal might have dried out a little with all the sitting. just something to consider, otherwise at 26k now, it is perfect. my favorite of the 4 bmws i have had.

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not sure if this was already mentioned, check the right hand side of the engine- gearbox interface. if it is dirty from oil seeping through and attracting dirt, you are looking at a know problem of a seal rubber ring in there failing and letting gearbox oil into clutch housing. if not addressed it will accumulate and eventually engulf the clutch which at this point will start slipping. and then you have to reaplce the clutch as well in addition to the s**t 1$ rubber ring. bmw never addmitted any wrongdoing and still offer the cr*p as replacement even though there are alternatives (forgot the name of the compound). this is due to their legal department i think, as if they admitted to making a mistake they would have to recall and deal with this themselves, so they just keep pretending nothing happened and there is no inherent fault in their ways. sometimes bmw people just make me want to grrrrrrrrr.... (you guessed it , i own a krs)

to replace the seal ring you have to take the whole bike apart, remove the gearbox which includes also partial engine removal (some bolts need removing so you can tilt the engine). the seal ring will fail at some point, when exactly depends on riding style, how much heat is generated in the clutch housing when shifting. so it's like living on a volcano, you know someday it's gonna blow :)

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