light kicks in the rudder pedal

I doubt its a Rotax 9 engine issue.

Could be you have something loose on the airframe/skin.

 it could be a airframe issue... I know it's not a carb issue, I was thinking a electrical problem, timing? Misfire? possible ?

Thanks

The way you have described the symptoms

"...feel in the rudder pedal very random and no particular rhythm some light kicks, I have no drop in rpm or change of sound from the engine..."

does not come across as an engine issue.

The lack of rhythm or enginenote/vibration change, the location (rudder) suggest something to do with airframe - could be internal or more likely external.

I am not familiar with your aircraft but from the photos, it looks to be largely fabric covered, including controls surfaces - I would advise a careful inspection of the fabric - looking for adhesion failures - how long since it was (re) covered?

I had this problem in the past on a Tecnam Sierra powered by a Rotax 912ULS (100Hp).

Those light kicks are usually sign of one cylinder misfiring or having anyway some combustion issues. In my case I later discovered it was caused by water deposit in the carburator sumps.

I recommend you open them and check whether for whatever reason water arrived there.

for me the issue was caused by the water separator funnel I was using for refueling, loosing his water separation capacity due to long term exposure to Italian MOGAS.

Is this a nose-wheel aircraft or a tail-wheel aircraft?  In-flight rotation of the nose-wheel might cause some rhythmic pulsations through the rudder pedals.