In English please lol
Anything can be accomplished with enough time and or money.
If you have the technical knowledge and equipment you could do like the Australian guy did with the CR500 engine and build your own counter balancer.
The KX 500 was not counter balanced like Skeens said. Installing a KX500 top end on a counter balanced Tecate bottom end is a option. To do it "right" a different counter balancer should be made when doing this or installing a Saber on a TRX250R bottom end. The Saber on a 250R bottom end still vibrates but not as bad as it would if it did not have any balancer.
Some guys have installed the Saber on the TRX250R using the 250R counter balancer but I do not know of anyone that is using a Saber for anything but drag racing.