Originally Posted by JanGeo (Post 37980)

Yes but they are harder to build being apposed and tend to puddle oil in the cylinders causing leakage past the rings plus have totally different valve train expansion problems - longer timing chains or belts or require long pushrods for the valves from a centrally located camshaft - longer intake manifolds for each head separate exhost headers etc. High performance boxer BMW motorcycles exhibited crank case stretching under heavy loads under race conditions. It is a great motor but it too has design trade offs.

Originally Posted by JanGeo (Post 38010)

Anyone with a boxer knows that the side stand use will usually result in a smoking left cylinder when it starts up again. The K bikes all have the same problem and BMW solves it with smokeless BMW motor oil and recommends using the center stand.