So if you find your KS Lev dropper seatpost sticking in the down position, here are a few easy things to try (especially if your KS Lev dropper post is new):
First, just double check that the cable going to the KS Lev dropper seatpost is setup correctly. A cable that has gotten pulled tight or loose, will defintely have an impact on how well your KS Lev dropper post moves up and down.
Also try adjusting the barrel adjuster for the lever/cable, as this will also have big impact on the movement of the seatpost.
Make sure the shaft is free of dust and dirt.
If everything is setup correctly on the dropper post...
Try this easy work around..(This is what worked for me, for my relatively new KS Lev seatpost)... flip your bike upside down (or hang it upside down) with the KS Lev dropper seatpost in the extended position (not dropped down), and leave the bike flipped upside down the night before you ride. This can help keep seals and the upper part of the post lubed. After leaving my bike flipped upside down for just one night, my KS Lev dropper seatpost stopped sticking when it was dropped. It seems as though flipping the bike over like this can also help re-lube your front and rear shocks as well, so if you find that they are sticking a little bit leave the bike flipped over for a night (as this seemed to help my Pike fork from sticking in the lower position).
NOTE: If you do flip the bike over onto the ground, just make sure not to damage any levers on the handlebars.
Also before your ride, you may want to drop the post and extend the post a few times to get the fluid in the post working up and down.
If you have an older dropper post, you may want to try applying Grease to the post like: SRAM Butter Grease - "When the post is clean, apply some lightweight grease to the top of the lower seatpost. You want to use the slipperiest lightweight grease you can find. Check out Finish Line Stanchion Lube. Slickoleum works great and so does Buzzy's Slick Honey. Use your finger to apply the grease to the post." See more here: Maintain and Repair KS Adjustable Seatposts
More discussion about maintaining KS Lev seatpost at MTBR.com here and here.
If you still can't get your KS Lev dropper post working correctly, you may need to get it serviced by your local bike shop.