GB,
Yep! I recall that H/D V4 concept was all the talk back in the late '70s. But because it was stillborn I don't think you could say Harley had a particular claim to it. I don't recall them even getting to the point of fitting such an engine into a frame.
There is a slight similarity between the Royal Star and the 1970's L4 Ducati Apollo, though. However, Ducati also never went into mass-production with that bike either, with only a few made as concepts for the american police market.
Regarding the Trihawk....
I always thought that 3-wheeler was cool. It was a shame that after H/D bought the rights to it they couldn't make a go of it either.
Any 3-wheeler with it's configuation consisting of two forward wheels, that has it's front wheels driven, like the TriHawk did, is going to be much more trackable and stable than one that has only it's rear wheel powered, and both of those configuations will be much more stable than the type with the single wheel forward.
Dwight
