Predius, Neither Buell nor Langen makes the engines or components. They are being supplied by a manufacturer. I suspect Rotax, but they sold the rights of this engine to HD back in the day. This is an important question for all the 1125 owners.
Ah, now I see what you're looking for specifically. I've only found one reference claiming specifically that the motor is assembled in Grand Rapids, with a design that is evolved from the original Rotax mill. That doesn't say who's making the castings/etc though, and I can't find anything quickly with more detail.
That looks OK. But Ronin looks better. This is what they need to do. Maybe purchase the right to produce those parts from Ronin and start mass production of these things