I'm a beginner on the CX2. I had a crash, and replaced the landing gear, upper lower blades, the main inner gear and the body. I took it for a 10 min flight and everything went well. The next day when I try to fly, it would'nt get of the ground. I thought it may be the battery, so I replaced it with a spare I have. The cx2 still will not lift. I gave it full throttle, I felt the wind strong coming from the cx2< the motors sound strong. I dont know what is the problem. Can someone tell me what may be the problem.

welcome to rcu with your first post. I am not a cx2 guy, but I'll see what I can do.

do you have a way to check the voltage of the battery pack? that would be the first thing to check out. If that is good and checks out, there are a couple more things it could be. One is also double check the voltage of the cells in your TX, I don't remember what people were saying was a good votlage to be above, but something like 5.2v or so.

Also something like one of your shafts could be bent, or maybe you got the motor too tight or too loose on the main gear when you put it back together. Teflon lube is probably the best to put on these heli's if you're gona lube it up. Also your motors if the crash was too hard could be going down hill.

hopefully some cx2 guys with some more experience can fill in here =)

Did you disconnect the motors from the 4 in 1 when you did your repairs? If you accidentally reversed the motors, they will spin in the opposite direction causing wind, but you wont get any lift. Hope this helps!

did you replace the lower gear onto the lower shaft correctly?
If the collar isnt secured to the lowere shaft on the flat spots it will slip.