New bloke from Australia

[Joolstacho]

Perhaps a Yamaha XS650 motor?
Traditional british looks, compact, electric start, powerful enough, 5 speed box, aircooled, plenty of spares availability and responds well to tuning; and has gained respect from trad british riders over the years.

Should not be too hard to find a motor?

See pic of one in a 175 Yamaha frame!

Richard

Amazing what a good engineer can do with Photoshop.
(And I think he might need a front brake upgrade don't you?)

[Brodie]

It would be cool to see that Rotax powered bike.

I have started a build thread over in other bikes.
Here is the link. https://www.a7a10.net/forum/index.php?topic=12909.0

[Greybeard]

It would be cool to see that Rotax powered bike.

Andrew, Beezermacc has that machine as his avatar.

At a meeting last year there was a BSA with a Honda fore and aft vee twin. Looked great.