When turning on the key to start, I get the single click. Here is what I have done so far with no success.

Strange, when this first started I could take out the starter relay, and then try and start it, put the relay back in and then it would start.

Here is what I have done:
1. swapped out the relay with known good, no luck
2. replaced the starter and I'm getting 12.35 volts to the starter, tried to jump the start (put a screw driver across the positive and ground) no luck just made big spark, and system made the sound like it does with you turn on the key for the first time.

Not sure what to replace next.

 

Start at the beginning which is the battery. 12.35 volts is only a partially charged battery to begin with(around 50%). Should be around 12.7-12.8 volts on a fully charged battery. Sounds like a small matter but this can make a difference in being able to start one.A battery can show 12.3 volts or more and still be bad.
Voltage can drop when a load is put on it. Have it load tested even if the battery is fairly new as I've had them bad straight out of the box.Here's a good read on testing batteries also.https://www.batterystuff.com/blog/ho...ry-is-bad.html Here's the main point of the article."A healthy 12 volt motorcycle battery should maintain a range from 9.5 - 10.5 volts under the load for a good 30 seconds straight. If the battery begins to hold and then steadily drops in voltage, there is a problem."

 

I have tried to jump start with jumper cables, but the same result - no start or turn over.

 

You can swap relays as both are the same and see if the starter at least turns over. If not then probably a wiring problem into the relay or even the fuse block has been known to have problems on wiring shorts. Also there should be a small circuit breaker up from the relay on the wiring harness that can be tripping if corroded. It will either be taped to the harness or in a sealed pouch. I've found them both ways like this.