My Dad had something like a "Whizzer" after WW2 called an "Auto Bike", but not as fancy as a Whizzer, and two stroke (Villiers) powered. It was heavy and English, so pretty much a POS, and he said he pedalled more than he "rode", ha ha!
I wouldn't mind a Whizzer, but 90 pounds is way too heavy, so I'll stick to my 20-odd pound, 35 MPH "Whizzer Wannabe", ha ha! Cheers, Terry.