Sounds like you've covered all the bases so I'd tend to agree something is up with the new caliper... maybe pics aren't necessarily needed (well maybe a couple of the caliper itself, one showing the alignment of the pads and rotor). If you still have the old caliper and if it's compatible with the new rotor that would be something to try! How does your caliper operate exactly? Just one pad pushes out and over and the other pad is stationary is that correct? Also the adjustment bolt, what is it adjusting? Forgive my ignorance as I'm new to karting and don't even have one (yet, building my first one slowly) but I'm extremely mechanically inclined and can fix/upgrade just about anything I can get my hands on. Don't give up! You're hung up atm (pun intended) but you're close to the solution!
Can't use the old caliper because A: the pads are almost completely worn down at an uneven angle due to the old rotor being warped and B: the adjustment bolt hole was stripped out. The new pads line up perfectly with the rotor. And yes, the one pad is stationary and held to the inside of the caliper with adhesive, while the other is pressed against the rotor when the arm is pulled forward. I'm thinking the new rotor I put on is moved over too far (its position can be moved, unlike the old rotor which was welded to the axle) and might be constantly rubbing on one side of the caliper, causing the brakes to drag. Not sure if that makes sense since the caliper sort of just "floats" on the rotor and it should adjust for that but...I've got no other ideas. Worth a shot.
Over the years I have alot of problems with the mechanical caliper setups.. most happens to be from alignment, caliper ability to move (float), and lubrication..
OP- Is the caliper bracket and the caliper internals greased good?..
Yeah, I can see why! These things suck. I was told they're easier than hydraulic...after working with them, I have my doubts. At least hydraulic calipers don't need constant adjustment, don't need to be in direct shot of the brake pedal, and are much more effective than mechanical calipers. I'm willing to bleed the brakes occasionally than deal with this nonsense...aaanyway...now that you mention it, I did forget to grease the caliper bracket and the caliper arm. I only greased the pivot points. That, paired with playing with the rotor's position a bit may fix my issues. We'll see when I work on it again.
As always, I will update this thread with any results. Thanks to everyone for the suggestions so far!