WR_450 in Turkey,
You want to check the backside of your top plate. You should see nothing but smooth grooves. If you see a dimple (a small circular depression) then we will warranty the necessary parts.
Let me know what you find, PM me as well to make sure you get a speedy response.
TC balls give more hookup at low-rpms. They also tend to make engagement a little more abrupt. On WR-450 models I do not recommend TC balls although some people prefer them. If you ride a YZ-450 off-road I recommed 5 TC balls for an 03 or 04 and 3 TC balls for an 05. YZs have taller gearing and increased mid-range torque. The 05 requires fewer TC balls because of a taller primary ratio.
If you have a heavily modified motor, you will also want to run TC balls. A WR-490 will likely need 5 TC balls.
TC balls do not come with the Yamaha