Dreams are good ... but there are lots of ways to "re-create" your dream bike without trying to import a Falcon. IMHO, you are on a fool's errand with this. Mark and Ferris have summed this up perfectly. The system is stacked against you. Importation Ain't gonna happen.

The Falcon is based on a XR400, but with a budget motor, body work and chassis. Budget everything actually. Why not convert an USA XR400 to a more dual sport/street based bike? Or just buy the Suzuki DRZ-SM with the 17" wheels? Better bike anyway.

Or get really smart and buy a used Husky 450 or KTM 450 Dual sport/SM type bike. Great deals around on 2/3 year old KTM SM's. Both KTM and Husky make street legal dual sports or Super moto bikes. Fun bikes!

You could also buy most of the Falcon parts in Mexico; like body work, headlight cowl, seat and more. Then simply adapt it to an XR400. My guess this would be possible with some skills and work, but in the end, a waste of money condsidering all the other good options we already have here.

IMHO, the DRZ-S or SM is a better bike than the XR400 in every way, and I'd guess is also better than the Brazil made Honda Falcon you desire. All current Honda 150's and 230cc XR's are made in Brazil and are imported to the USA. Shame they left the Falcon behind, but there are reasons for this.

Lots of equal or better alternatives here if you look around.

BTW, it costs the OEM "about" $100,000 in fees PER BIKE MODEL (paid to DOT and EPA) to certify a machine for US importation and takes 6 months to a year.