How to change a headlight bulb on a 1993 honda nighthawk 750?

First, test for voltage at the plug that attaches to the headlight, if you have voltage at each terminal when set to it's respective hi or low position it could only be your headlight. If you don't have voltage then you need to work back from the wire to the switch and etc etc

My battery is not charging I change the stator and order. Still not charge the battery

the fuse box is behind your headlight

It's in your wiring you will have to chase it down hope this helps Merry Christmas

i have found in the past its the cable not the tacho

check the bulb and the wirirng

The two most likely culprits are the ignition switch and the starter button. The starter button, in the right handlebar switch assembly, performs two functions: cranks the electric starter - and, at the same time, turns off the headlight. Sometimes the electrical contacts inside the starter button burn out and fail to reconnect the headlight circuit when the button is released.
You can easily determine which one is the problem by simply checking for battery voltage at the headlight fuse. No voltage means the likely cause is the ignition switch. Also inspect the large plug on the bottom of the ignition switch. Sometimes the individual connectors will corrode, melt, or push themselves out of the plastic housing.
If there's voltage at the headlight fuse, then plan on replacing the right handlebar switch assembly.

Hi and welcome to FixYa,

With the indulgence of DickCanFixIt...

Almost always, in instances such as you have described, the main 30Amps fuse of the 93 CB750 (F2P Retro) would have blown. The main fuse is located along with the starter relay. To locate the starter relay, follow the + cable from the battery terminal.

Additionally, once power has been restored, you may want to check the regulator and CDI as they are electronic and therefore prone to damage on reverse polarity.

Good luck and thank you for using FixYa.