The first K100 was produced in 1983, but it really started to be on the market by the end of 1984.
Amazingly, 26 years later a lot of them are still on the road and in very good shape.
Over the years, BMW produced different flavors of the K100 (RT, LT, RS and RS 4 valves). They also produced a K1100.
By 1989, BMW had solved the majority the problems encountered in the earlier version.
You can see the evolution of the K100 Here
Mileage is not a real issue as you can ride them for ever (I have a K75 with 350K and original engine). If you find a bike with less than 50K, it should provide you with many many years of enjoyment.
Price.... depending on the condition, mileage and accessories, you could expect to pay as low as $1,800 and up to $5,000.
Why buying a newer one?
On the early K bikes, the engine output shaft had only 6 rivets. The newest ones have 12
By 1986(?) the drive shaft was replaced (one more spline).
The latest K100rs have a 4 valves engine.
Why buying an older one (1985 K100rt)?
10 more Horse Power.
Start to look around, and before buying one let us know what you found. Depending of the year and the model, we will help you to ask the right questions.
Usually, BMW riders are honest and they will disclose any problem but....... you could always find a rotten apple in the bag.