I love the Nimbus design (see link here). It’s like rolling industrial art. I’ve never heard of the Ridley. Really interesting bike. Kind of like a Cushman on steroids.
Ted Writes:
Hi, Steve. I enjoyed seeing the unique and rare Harley-Davidson motocrosser, featured on your site. Speaking of unique bikes, one of the more interesting I’ve ever come across is the Ridley. Produced right here in the USA, these 3/4 scale cruisers feature a 500cc v-twin engine, and fully automatic transmission.
I spotted this one at an Ohio Valley BSA Owners Club meet. Check out the old Yamaha IT200 parked behind it for a reference to its diminuitive size. 
Also included is a photo taken at the same event, of a Nimbus. I’ve not done any research on the brand, but I believe it was produced in Sweden. A very interesting mix of engineering. Note the perimeter frame, yet exposed valvetrain. 
Ted
As always, Much Appreciated!
Motorcycle Photo Of The Day 