A friend was asking me what class you would run with a production dirt bike produced in large quantities. If it had a street version as well with the same frame and engine, would that make a difference? Could you "make" it into a street bike by swapping the street pieces?
I read the book and could not come up with an answer.
Just my two cents worth.
Since frame and engine numbers are not checked I would say if you wanted to spend the time and money to convert a dirt bike to a street bike and run Production, you could.
..The cavate is that the bike MUST appear identical in all respects to the production model it represents. That would mean it would be necessary to add Full lighting, production exhaust, air box, frame, forks, wheels, brakes, gas tank, fenders and seat (and many more misc items) to make the dirt bike legal.
By the time you spend all of the money, and spent all the hours, necessary to bring the bike up to Production specifications you'd be better off buying the street model of the bike to began with.
Buzz
