New relay soliniod and starter
Okay, the solenoid has a plunger in it. When you push the start button, the plunger is pulled into the solenoid. When this happens, two things take place. One, the plunger is connected to a fork that moves the starter drive (Bendix) outward to engage the ring gear on the outer clutch drum. Two, the plunger pushes on a shaft that has a large copper ring on it to make contact with the two large copper contacts in the solenoid end cap. If the end cap is cracked, the ring may not make contact and start the starter.
Make sure that the spring and shifter fork are assembled correctly. The ends of the fork on the starter drive side must be in tracks on the Bendix. The spring, cup, and pin must be assembled correctly in order to move the starter drive gear into mesh with the ring gear. You should be able to pull on the plunger that goes into the solenoid and feel the starter drive move forward and backwards freely.
Install the solenoid and connect all connections. Once you have it all hooked up, make sure the bike is in neutral. Using an old screwdriver, short between the small terminal with the black wire on it on the back of the solenoid and the large terminal at the top of the solenoid with the battery cable coming from the positive post of the battery, Does the starter turn the engine over. If so, the problem you have is electrical in nature, not mechnical.
Now, using a test light or volt meter, touch the small terminal on the solenoid with the black wire on it. Turn on the ignition switch and press the start switch. Do you have voltage there? If not, go back to the starter solenoid. Here, just like on the solenoid, you have three terminals. Depending on which starter relay you have, you may have two large large and one small or three 'tabs". Put your test light to each terminal one at a time and press the start button with the switch on. One wire should have power to it with the button pressed but lose it when you release the button. Do you have voltage? If not, your problem is in the wire running from the starter relay to the handlebar switch.
Now, since there are two black wires at the starter relay, one from the switch and one from the starter solenoid, make sure you have them on the right post of the relay. If your solenoid came with instructions, make sure you have the wire from the solenoid connected to the correct connection on the relay. If you can't figure it out. Turn the switch on and press and hold the starter button. One of the black wires should go "hot". Touch that wire to each of the terminals on the relay until you hear it "click". When you hear the click, this is the connection for that wire. Hook the "hot" wire to one of the other terminals and the black wire going to the solenoid to the other. Now, when you press the start button, the solenoid should "click" and power to the small terminal on the starter solenoid.
If neither of the black wires goes hot when you press the start switch, the switch is probably bad. Those are the same switches they used on the old Shovelhead bikes and they weren't that good. The replacements you buy today are pure junk, made in China. You may want to upgrade your handlebar switches to later model switches.
Let me know what you find. I may have to move you off forum in order to provide additional help.
Good luck
Steve
