I guess every 20 or so years is jumping pretty quick, changing stuff, EVO has been around since 85, now it's a twin cam, how many jap bikes you know had the same engine for 20 years, in fact how many 20 year old jap bikes can you still get parts for?

How many Jap bikes are using the same engine after 20 years or can get parts for? Kawasaki Concours until last year after a 20-21 year production run with very few changes and until a couple of years ago, the Kawasaki Voyager XII after something like a 19-20 year run. Both bikes were changed very little over that time.

As far as replacing the EVO motor, times change and things change with them. In the mid-1930's, the Cadillac V-12 and V-16 engines were the untimate. Haven't seen too many of them around lately....