new coil and plug wires/no powe

Hi I have a 1979 kz 650b. I put on a 4 to 1 pipes 2 years ago, more recently I cleaned the carbs to stop a overflow problem (readjusted the floats which may be a bit high) and  new coils last week. other than that the bike is stock and ran great before I worked on it. Now it starts and idles  fine except it has no power. It sounds and like rides a bogged down bike going through sand.. It tops out at 45 mi/hr at 5000 rpms in 3rd gear before I have to shift to 4th . The new coils came w/ plug caps that screw on to the wires and I have to take off or unscrew the tip of the plugs for the caps to plug in (connect)  to the plugs in the cylinders. Could the screw in plug caps or cheap coils cause my bike to have such sluggish throttle response. Or any other suggestions anybody might have would be great  THANKS george

A good gauge for performance is reading the plugs. Pull all of them and note which plug came from which cyclinder. Post pics. 

i will THANK YOU