Looks interesting. Keeping up with reading the bike mags this is a motorcycle area that is rapidly gaining momentum in the UK. Take a worthy '80s bike - often parallel twin - something that wasn't too cool back then but has a certain charm now and restore it. But not with original parts, lots of home made stuff and stealing from modern machinery and basically doing what we all wanted to do back then but there wasn't the parts available.
Me, I'd love to get a Kawasaki triple, (500 or 750), in an Aprilia RS250 frame and running gear.
Or a Laverda Jota engine in any modern superbike chassis.
Or any solid Honda single overhead cam four. 400, 550. 750. whatever. These were the mainstay for everyone back in the late seventies, once you moved up from the two strokes.
But Yamaha did some good four stroke triples as well. XS750s I think they were.