This bare Harley-Davidson 1973 Harley SS-350 frame and swingarm is on its way to me. This was kindly given to me for just the cost of shipping by a Facebook contact in Illinois.

As somebody who loves horizontal singles, I’ve long schemed about how to make a Ducati Supermono replica from a production Ducati twin, by fabricating the same sort of reciprocating balancer arm that the Supermono had, but designing it to bolt onto the standard crankcase in place of the vertical cylinder. [EDIT: I’m not the first to thing of this.]

I’ve also sort of wanted an Aermacchi single for a long time. However, I’d pragmatically scratched that off my bucket list because they’re a bit fussy, and parts for them are getting pretty rare and pricey. Aermacchi ownership requires being an Aermacchi guru; that just wasn’t a rabbit hole I wanted to venture down at this point in my riding career.

Why not see if I can combine those two wants into something do-able? It actually makes sense. In an existing Ducati chassis, it’s an emasculated engine with one cylinder pointlessly cut off it. In this frame, it’s a replacement engine that’s more modern, more powerful, much smoother, and (potentially, if desired) more displacement and fuel injection.

It’s still little more than a conceptual exercise at this point, but I’ve started playing around with it, as this Photochop illustrates.

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