New carb needed

My carb needs replaced its on a 2001 Xr 650r and bike is stock. What's a good replacement that will slide in place of the stock one with out any modifications that I can buy in the U.S. Links would be appreciated.
Thanks

Is this the factory carb?

http://www.partzilla.com/parts/detail/honda/HP-16100-MBN-673.html

PE78C B - 16100MBN642 this is the part number that i know about and it cost over £700 here , so the partzilla part has a different part number and its much cheaper , i am not sure about this but i know what i would do , get a mikuni TM 40 and never look back .

Or look at eblay for a second hand one , they go cheaply .

Mad Frosty wrote:.... get a mikuni TM 40   and never look back .

+1
Simplest pumper for this bike, setup easy, fits like a glove, and is lenient to altitude differences.