runs a little rough at low throttle

[gazza2010au]

hey guys got a GSX 97 800 motor just rebuilt it now im not sure if the rotory valve is slightly off timing or if i ground off the valves to much when riding the ski at low to low-medium throttle the ski runs rough any throttle more than this the ski runs great i pulled the carbies apart and cleaned both with carby cleaner what could be the problem?

 

[Dr Honda]

Well... it's a 2-stroke... so rough is relative. They don't run perfectly smooth, but if you think it's excessive, then I would verify the rotary valve, the ignition timing, and the motor mounts. (a loose mount will cause low RPM rattles and vibration)