rnning of the enige

[Helios]

Since a short wjhile now i 'am the proud owner of a CB 750 F ( bol d ór) 1981. The enige is running properly howevr when I'am driving on nthe highway at a speed of appr. 120 kh p.h everythin is oke. but when i try to accelerate , the engine is sputtering and smoethies holding back. It feels like the ignition is not properly set or somethoing might be wrong with the carburator. Does anybody has this same problemand how this canb be solved
 thks Helios

[LukeM]

Might be a problem with the spark advance unit.  It's on the left side of the engine, behind the spark trigger units.  Check for stickiness in the unit.  

Luke M