Please help!! This thing is driving me crazy!

I bought a Roketa 110 atv from a buddy at work. It hasn't run since last spring.. He gave me a brand new battery(which I filled with acid and charged before install)

With the key on, brake pulled (brake lights come one) and push the start button, the solenoid clicks. Logically I tried to short the two posts on top.. No sparks.
When jumpering from positive lead on battery to the post on the solenoid that goes to the starter, it turns over and tries to fire.. But does not.
Same thing happens when jumpering from positive battery terminal straight to the lead on the starter.
I replaced the solenoid with a new one.. Same deal.
The kill switch near the rear of the atv is completely disconnected. The red and black wire loom and the green and yellow wire loom are just hanging.

Am I looking at a wiring issue or something else? Any help is appreciated!!!

 

There is a problem with the heavy lead from battery to solenoid, either corroded terminal on the battery or solenoid, or a break in that wire. Fix this first, it may be causing the non starting.

 

Thank you for your response.. Sure enough you nailed it!

I found a crimped connection at the positive battery terminal had come apart inside the heat shrink. It wasn't visible to the eye, but your advice made me check all of the positive battery cable connections.
After this fix and a little carb cleaning, the boys rode all evening! Thank you again for your advice.. The simple things are usually the most difficult to find.