Some 2005 Whizzers are rare and worth more money! The very first 2005 models had a 26 MM carburetor and a really great head design. The early 2005 were by far the fastest of all production bikes. Most exceeded 45 MPH right out of the box. Whizzer USA modified most of them [slowed them way down] and I purchased almost all the original 26 MM carburetors [none left]. The best way to identify the fast Whizzers is by the size of the carburetor [unless they were downsized], the head had a dull finish, and the ID plate on the frame shows a 2004 mfg date.
On the downside, the lifters MUST be replaced with mushroom versions right away as either the camshaft lobes will be trashed, or the lifters will wear very quickly. The 2005 also has the needle bearing in the sidecover, whereas the later models converted to a ball bearing side cover [not as good].
Have fun,