Sport Evo flat spot???

[Holjon]

Hi guys, just wondering if this is a common fault and if anyone else has experienced it. If so how do you think I should go about solving it.

The problem is:
At about half throttle (sometimes at full) there is aflat spot in the acceleration around 3500-4000rpm. Also when the revs are dropping, at about the same point the exhaust starts to pop.

Any help is much appretiated.

[Demlotcrew]

If its missing then check the ignition first (plugs/leads/cap/rotor)