RC18,
take a close look at the upper gear that drives the lower rotor. you'll see a notch where the two interconnect. this notch didnt seem to get formed well when they did the molding process so it does bind a little.

this is an easy way to get around that: take the upper rotor off, slide the middle spacer off, and then pull the lower rotor off. if the upper gear tries to pull up with the lower rotor, then you'll know its binding. you've got two choices if this is whats happening, both are easy to do. one, when you put the lower rotor back on, dont push it all the way down onto the notch of the upper gear, just a few millimeters so it'll drive the lower rotor. then, put the middle spacer back on, then the upper rotor, and see if it has freed up any.

if it's still binding, take the rotors off again and take a small file and sand the notch on both the rotor and the gear. put it all together again and see if spins easier.

one other usefull mod is to completely get rid of that plastic middle spacer. there should be two peices of silicone tubing on the heli. one that holds the upper rotor in place, and one on the bottom of the tail motor housing. take whichever piece is longer and cut it in half. take the upper rotor and plastic spacer off and slide one of the peices of silcone tubing down onto the rotor shaft till it's flush with the lower rotor. this will hold the lower rotor in place. next take a 2nd peice of the tubing and push down onto the rotor shaft about a half inch and place the upper rotor back on, then simply put the 3rd peice of tubing on the shaft to hold down the upper rotor. its saves weight, reduces drag on the system, and also gives a little more clearance between the upper and lower rotor so they wont clash as easily.

on a side note, my bearings and CF came today. took almost all day to do it, with lots of swearing and a little pain, but i succesfully replaced the stock rotor shaft (had a slight bend in it) with new CF and installed the bearings. the rotors have almost no wobble in them at all, maybe 1 millimeters worth, which is a far cry better than what it was. i still have a little bit of binding to fix, but despite that, my flight times have increased to over ten minutes (only got ten minutes before if i didnt use the tail motor). it was a pain in the butt to do the mod, but it is certainly worth it.

nick