Did you notice any play in the con. rod small end, bearing and piston pin when you installed the kit? Something there could be slightly out of tolerance, so check your service manual for proper specs. Sometimes "one size does NOT fit all" and an appropriate diameter needle bearing must be used to compensate. Your service manual should mention which ones are available.
This situation causes a rattle or clattering sound in the engine at all revs -- not to be confused with a knocking sound that indicates the big-end of the con. rod being out.