Kawasaki Part is more expensive? why?

Kawasaki part is more expensive because the quality of kawasaki part is more better than another bike, let see an example of motorcycle part, gear set part. On the kawasaki low cc capacity motor bike, price for one gear set between $17-$20, defending your country, and for another bike e.g Honda motorcycles part or Yamaha motorcycles part, price for one gear set, between $13-$15 / pack. Now, why