Why did the CBSA decide to fine you? Did they think that you were trying to get the bike across the border without paying the customs due for the value that was added to the quad when all of the engine work was done in the USA?
Did you fail to provide proof that the quad originated in Canada, crossed into the US and now it was returning home to Canada?
I am just trying to understand what went wrong and how to prevent a similar situation from happening when I ship stuff to Canada