strange oscillation in handlebar/headset between 50-90Km/h

[Pastorius]

My KTM dealer told me that it may be due to the front rim, since it is a little bent in off-road duty.
So i decided to make it centered. After that I have got the same result.
My KTM dealer then has suggested to me to change the adjustment of fork or rear shock, but i am not very convinced.

May it be the front tyre that is in bad condition?
It is a Pirelli Scorpion, it is four years old and is in the middle of Km life (knobs are in half life level aprox.)

Any suggestion will be grateful.

Best wishes.

Jose Bernabe
KTM 990S 2006
17500KM
Murcia (Spain)

[mudpao]

1. Change tires (f/r) to new ones. Tyre life is limited...
2. Have the wheels go through a static balancer since tube type wheels cant be balanced on them electronic whatsit balancers... (so the shops would say)