Sportbikes like the R6 are designed for racing on the tracks, but most end up on the street. Either way, why would they be called replicas if they are designed and sometimes used for racing? Wouldn't they be real racers?

WHY SCRATCH WHEN YOU ITCH??

Usally they have a demand for the bike, or an interest on the market saying they would buy something like that. And then they take the stock item and modify it to a racing spec. Like Chevy corvette, its stock for the general population, special factory ones that are more powerful, limited, and expensive, but the racing teams start basically with the same car and build it up so that its faster and more designed for what they want it to do. Like a C5-R instead of a C5 or a C5 Z06. Or take a company like subaru and mitsubishi who make a "Rally Inspired Car" that is still faster than most cars out there but add options like viscious coupling to improve the AWD, and turbo, lower suspension and etc. Different models with more power and options, etc etc.

So it really comes down to a supply and demand. If a bike is well made, and there is a public demand for a bike style they can produce it and make some money. Give people what they want and they will buy it if its reasonably priced. I know Harleys are not like a supersport bike in any way, 2 completly different riding styles but some people just wanna ride for the cheapest. And if you can get a new R6 for about 8 grand why pay 16 for a harley if all you wanna do is ride and dont care what your under. That was my justification, i wanted a harley but didnt have enough money so i bought what i thought was the next best thing, and R6

i could be wrong but i always thought when they said race replicas, they meant basically a street legal version of the race bike. like the an R1 in the Galuose (not sure of spelling) paint scheme. or a nicky hayden RC-51, or the honda in the Respol paint job. i always thought those were the race replicas.

Race replica's or repli-racers, are terms used to discribe bikes that are the same platform as racing counterparts.

The r6 and other 600's run supersport classes. But the YZF600 doesn't so it's not a replica...

In other words it's a race bike that has been replicated for use on the street. Got it?

Ohhhhhh. That makes a lot more sense now! Thanks.

Pretty much as above -
for the manufacturers to race in championshipes such as WSB they have to make 500 road versions of their race bikes before the season starts and then show that they can produce x no. every month following (not too sure on the numbers here but the principal is correct).
This is how road bikes are primarily developed and introduced because the manufacturers all compete for that racing crown - which only stands to benfit us as we see things like slipper clutches and other trick parts find their way back to the road bikes.

GP bikes differ in that they are purely prototype and cannot share any parts with their road going / racing 'lessers'.