YZF600R

A Shift Kit is a kit that comes with a ball bearing detent arm, a stronger shirt shaft spring, and a new gasket. It reduces the likelihood of missing a shift. The stronger spring keeps the detent arm roller from stopping at the top of the star wheel at the end of the shift drum. The ball bearing on the upgraded Detent arm reduces drag, which adds to the effect while overcoming the additional effort required by the stiffer spring.

Here is the link to the Factory Pro site:
http://factorypro.com
http://factorypro.com/products/shift_kit...y_Pro.html

Here is a link to the installation How-To:
http://yzf600r.reserector.com/phpBB/howto7.html