OK now we can go further. It probably needs to have these things looked at: rotor head fit and flybar fit.
About halfway thru this bulletin is a section on the "sticky collective" problem.
This bulletin applies specifically to the CP but if you look at the info it will be very useful for you as well, and might lead to soving the problem.
http://www.horizonhobby.com/Products...rodID=EFLH1100
Note especially the info on the bearings and the step washers.