My bike is the ´85´K100RT with 136,000 miles on it. I bought it very used and abused.(47,000) 1st; If you buy ANY K-bike, physically remove the rear drive and inspect the input splines (pinion gear splines) for wear!! The drive shaft splines can be checked by removing the shaft itself using a rag to protect the splines while you clamp a pair of vicegrips to it and rap the vicegrips with a small hammer. The driveshaft is held in with a snap ring at the transmission end. Good photos on line of what the splines can look like are available on line from Hansens MC shop in Medford Oregon at their web site.(They also have a rebuild service for these splines) The rear drive gears are a MATCHED SET from BMW and look to spend a cool grand to have your rear drive completely rebuilt by BMW using new gears. Hansens re-welds and recuts YOUR input spline. IF you test drive the potential K-bike and you have difficulty shifting it then suspect the additional lever pressure required to shift it is due to worn clutch disk splines located on the engine side of the transmission!! You cannot examine these without jacking the entire bike up because you will have to remove the center stand and THEN the transmission. A good input spline to the transmission will allow almost buttery foot shifts with a properly adjusted clutch. Look to spend another cool grand if you have to replace this shaft to the transmission as the gearbox has to be dissasembled and reassembled with the proper shims for end play. Check the lower rear monoshock stud (epoxy´d into the rear drive?) I allowed the nut to run slightly loose and this seemed to have contributed to it SNAPPING OFF AT 70 MPH dropping the entire weight of the bike onto the rear fender plastic lining. It was a lock up situation and fortunately I wasn´t in the middle of a curve and didn´t have a passenger on board at the time. I have done a ´survey´ of k-bikes at the Trenton, Ontario rally and found no fewer then fifteen similar experiences with this mounting stud breaking. If the handlebars are bent from falling either live with it or replace them. DO NOT try to straighten them as they seem to be a ,albeit lightweight, alloy steel that seems to be overly brittle. I did a stupid modification to my bars trying to gain clearance for some aftermarket braided brake lines. The result was that these unforgiving handlebars ended up in two pieces in my hands while riding it! Fortunately I had cleared a busy intersection and was only doing about 30mph when it went into a violent tank slapper as the bars broke in half leaving me nothing to do but to LEAN the bike off the road into the grass. My gripe with the handlebars is that it is of a brittle rather then malleable metal. A little warning from bending first would have been appreciated. The engine seems about bullet proof. Compared to my 93 Concourse that needed a valve adjustment/check every 6000 miles, the K really shines. Like 70,000 miles without the valve cover being removed. I usually stay out of the 6-8000rpm range and accelerate moderately. It was at 30mph that my transmission input spline stripped in less then a second with no warning other then the extra pressure on the shift lever. IF you see oil in your overflow tank to your radiator it is most likely that you have blown the seal between the water pump and the oil pump as yes they are on the SAME SHAFT and all that separates the two incompatible elements is a single neoprene oil seal. At first I thought that I had blown a head gasket until I researched the flow of the coolant system. The replacement oil/water pump is an upgrade as they did have trouble with the original pumps. Don´t try to rebuild it, replace with their upgrade and be happier although more dollars. DO NOT use any oil additives to the engine!!! The same engine oil circulates onto the starter motor sprague clutch assembly and anything slicker then the stock oil, ie Teflon, Moly, graphite etc. will lube the clutch into NOT ENGAGING!! IF the K bike you are looking at has trouble engaging the engine then look to replacing this clutch with the process being the same for removing the transmission!...........Conclusion. I can ride a whole season,20-30,000 miles, one one spline lube of the input side (engine side)of the transmission/clutch spline. THE REAR DRIVE NEEDS TO BE LOOKED AT EVERY 3-4000 MILES. LUBE IT OR LOOSE IT!! I have friends who have tried every sort of lube to include stuff designed for bulldozers in high heat desert conditions. Don´t ignore this maintenence or you WILL eventually pay for it. The good news???? The K-bikes seem to be one of the biggest bang for the bucks in the used bike market IF you pay attention to the things I have brought up OR you have a reputable shop to entrust the work to. With the exception of a floor jack, YOU can do all the maintenence I described out of the original tool kit that should come with the bike!!! Try THAT with any other brand out there. Rear drive/shaft spline lube takes me about a half hour, no biggie. The annual transmission removal is three to four hours for me, same for starter clutch replacement. Do them both at the same time if you have any concerns about the starter clutch. I have replaced BOTH bolts on the rear monoshock with metric coarse thread grade nine bolts. So far no problems after 30,000 miles. I do however have a crack in the frames mounting flange waiting to be welded. I have Honda (1978) Gold Wing bars that are much heavier in metal content but I haven´t had the bike fall over to test their strength/resitance to bending. If you ever are on a bike with catastropic handlebar failure you will never forget the experience and thus the Gold Wing bars. Of the K-series the three cylinder is far smoother then the 100/four cylinder models. The 100´s love the open road and 70+ is a sweet spot. But there is inherant vibration to this engine that needed a counterbalancer but never got one. It is livable though as I have done 1400 mile days on an emergency trip without numb hands. (don´t know about the K1200 series). My RT fairing does the job of protection as good or better then anything out there. It is DATED in style though. The fairing IS made out of genuine fiberglass and NOT some ABS Bull crap plastic like my Concourse. (The Connies had fifteen hundred dollars damage falling off the side stand!!!) Fiberglass can be repaired yourself or take the pieces to a local body shop. I can ride for two hours at twenty degrees without any electric suits etc. Just layer up and a good winter set of boots and gloves. The saddlebags hold about all you need and I have a Givi top box that I highly reccomend to anyone. An excellent product that is better then BMW´s. (Cheaper too) The flying brick K-bike is beauty to some but to most it is an orphan bike. Most BMW dealers need to order the parts even though the series is still being made today. BMW North America was slow in my experience in getting me back on the road with the matched set of gears having to come from Germany in two weeks time. NOT what you want to hear when you are on vacation 2200 miles from home. These are the major points. It IS a 2-300,000 mile bike if you get onto the maintenence. There are other quirks with sending units, turn signals etc. Be aware that BMW has CLOSED alot of Mom and Pop old time dealerships and are funneling the unfortunate riders into Harley like boutiques and thinks that it is nothing to travel 100 to 200 miles for your routine servicing. It would be nothing if they lent you a company bike to get back home with!!!Write for more... Best of luck !!