Do you have a pic? The stock setup on a CB450 is a separate regulator and rectifier; two units. The regulator has three wires coming from it (most commonly they are green, black, and yellow, but this can differ by year). The rectifier will have four wires: Red, green, yellow, and pink.
When replacing the two stock units with the Sparck Moto combined unit, the yellow and green wires from the regulator are no longer needed and should be secured safely so they don't flop around or are given a chance to contact anything. If you're wiring your bike for LI-ION use, you won't need the black wire from the old regulator, either.
Next, the old rectifier can be removed and the new Sparck Moto unit plugged into it's place. This will leave just the black wire from your new R/R. If running with an LI-ION battery, this black wire should be connected to the positive terminal of the battery (you may add a fuse to this connection, if desired). If you're sticking with lead acid, this black wire should connect into place where the old regulator was removed (that spare black wire described in the previous paragraph).
Lemme know if I can help with anything else or clarify the instructions.