I think this is an interesting thread, but a few things bother me: One, a
H-D engine is not at all reliable, fuel efficient, or powerful for it's
size, in Motorcycle Land. The design is certainly an outdated, archaic one
at most. The sound is nothing short of a souped-up, unmuffled Maytag (for
those that can remember back when washing machines were powered by
2-cyl.,2-strokes). The engine is really only (somewhat) capable of pulling
around the motorcycle's weight, and is not stressed, internally, to pull a
vehicle 10 times that reliably-even IF you add a few more engine units. If
you really like the idea and the sound, there are a few other MC twins that
are built strong and are reliable- Ducati and Moto Guzzi. Listen to one of
THOSE unmuffled ! Now THAT is an exhaust note (IMNSHO) !! Honda tried the MC
engine-into-car idea once: the 600. Remember those little buzz-bombs? Didn't
last, didn't get fuel mileage. Besides, there are numerous dependable and
fuel efficient engines that work so well, to transplant easily into our
vans. A little exhaust tuning, and who knows- MAYBE it could sound like a
Ferrari !  Porsche 911s/Turbos sound super, are reliable, AND are fuel
efficient for their HP.

Karl
'87 Syncro Westy
'92 DUCATI 907ie