I've done it a couple ways. 1) Drove across the border with a race bike in the back of the pickup. No questions asked. 2) Seller dismembered race bike and sent it to me in 2 crates as "parts".
In my recent experience, import brokers haven't a clue how to import a race bike. Read the stuff in the link I posted above and do it yourself. I did.
Since it is a race bike, this method is the easiest: 1. Find a Canadian racer that is racing in the US soon, hopefully at a track near you. 2. Have that racer receive the bike for you. 3. When said racer crosses the border, he/she just says "it's a race bike." Generally, no questions asked. 4. Meet racer at race track to complete delivery. Pay racer tons of cash for making it work. The last time I brought in a bike from Canada I was very lucky. It was an RZ500 unfinished project. I saw it in person during a business trip to Toronto, and the seller was a cool guy. Told him it was sold if I can figure out a way to get it to my place. A few weeks later, I meet a Canadian Endurance team during the WERA National at TGPR. He lives near the seller, and agrees to pick up the bike for me. About a month later, he brings it to the next round at Atlanta Motor Speedway, about a 90 minute drive from my house. I paid him US$200 cash. He was very happy. If I had to pay him US$500 I'd still would have been happy. This was in 1998. Happily, I still have the bike. Sadly, still haven't touched it. Yet.