Here is a video of my lift… I need help managing the weight of the cubes. It picks up skyrises like a charm but those cubes… :o
Vex continuous elevator lift problems - YouTube
Here
you just havent braced the lift using a beam to form a triangle with the base
for example like this:
Also, when your lift goes up, the green slides fall out at full extension. If you notice, when you were going down and it got stuck on the bottom linear slide truck because they are not 100% lined up. If you simply add a screw to the bottom of the 2nd stage linear slides, it will act as a mechanical stop so this binding wont happen.
If I’m too confusing, P.M me and I’ll try to clear it up. 
sorry my lift has worked perfectly except choppiness with cubes. that green slider was not supposed to happen… i must have something wrong because i specifically designed the lift to not go past the top green slider so it didn’t have an edge to get over:( thanks for the suggestions any more would be greatly appreciated
I believe you’re issues come from your chain skipping from the sprockets. Bracing the lift like stanley mentioned should help keep the lift from wobbling and thus keep the chain constant. If you can also keep an idler sprocket on the chain, that should also help keep the tension
I should probably do a new video, my chain might slip but it is very minimal and only for the first inch or so of my lift going up. I am bracing the lift but am wondering if the choppiness could be fixed by the brace of if I need to get some white lithium grease or all of the above. everything that people have posted so far I have already thought about I am working on. If there is any fixes that have not been mentioned it would help. I am thinking that bracing the lift will fix a lot of problems but if there is any other flaws I do not see them.
Thanks guys.