Engine Shocks / Jerks problem in Honda CBZ Classic. What to do?

I own a pretty old honda CBZ classic. The model number for my Honda CBZ classic is 2001 and it was working well but from few month it had started giving me problem. The problem is that at the time when i start my bike it start giving jerk on 2-3 gear it feels like someone is pulling from behind. to get rescue from this problem i went to the mechanic and have Clutch plate changed (Hero orignal part, Changed oil, changed the spark blug almost everything but the problem is still continuing what should i do.

Please rescue me from this problem.

it could be your driving speed by which it giving you a jerk. Like driving on 3-4 gear without accelerating the speed. Is it?