I was messing with my old GL1000 this weekend and happened to look over at the Valkyrie and I think I had a religious experience. Maybe it was the IPA. Anyway, the perspective made me want to ponder it a bit.
The Japanese motorcycle manufacturers have done us all a huge favor. Technological evolution, I think, is more apparent in motorcycle engineering than just about anywhere - and the Japanese have shown us the way.
Harley Davidson (and the many v-twin makers of old - American and Italian) started out with a good idea. The early vertical twins (think all the Brits) joined in and those technologies rolled along for 50 years. Pretty much unchanged. I suppose we can't exclude the BMW design - which also is very old and saw very little in the way of real evolution for a half century itself.
Japan was silent to the world of motorcycles. Until after WWII. Honda, in the span of a few decades, quickly progressed from tiny singles and then more and more sophisticated twins to the world class inline fours and ... horizonal fours. From the GL1000 to the GL1500 - and 1800.
I mean, look what they've done with the inline four. The CB750 set the world on its ear. It and its descendants (and competitors) have seen more refinement since 1969 than (in my opinion) the V-Twin has seen in a hundred years. Yamaha's R1 in 2009 introduced "cross plane" technology or "big bang" firing order to the I4. If you've never heard one, you're missing out. Who knew a straight four could sound like that??
Anyway, this was my epiphany. My IPA moment. For a split second, I felt the timeline of that evolution in my veins. I have been lucky to have "come of age" during motorcycles golden years. (70's until now). I've enjoyed a bunch of them. But, dagnabit, there's not enough time (or money) to enjoy them all.
I'll give it a shot.

