Whenever I give cyclic, bot blade & top blades switch posiiton, with another cyclic they switch again.)..Whats is wrong here? Should I give cyclic while blade tracking?

Things that I've check = all screws are good, head leveled, flybar leveled at 0 at mid stick, thrust bearing in correct direction, changed new o-rings, straight feathering & main shaft, blade grip is good & tighten but still can turn.

Note: I have perfect tracking with this blades for the past 50packs until I changed to DX7. Btw, this is for my belt-cp

blades balanced? is there some servo interaction? do you have any mixing on?

I'd check that you are on the proper mixing setting in the dx7, it should have one for cppm helis.

SwashMix is +60,+60,-70. Blade is balance. Servo movement is fine, I changed to DTS, Anymore suggestion?

Have the blades been in a crash? or even a minor blade strike?. if they are cracked or something near the root of the blade it might cause that due to flex in the blade. or posibble lateral play in one of the bearings in a blade grip, I am just throwing out ideas here as I dont have a real clue but it's something to look for.

Nope, this set of blades are as good as new. Like I said, I never had blade tracking problem until I changed to DX7. Either I got lucky the last time or some is really wrong with my head since my entire plastic head set has gone through at least 100 packs without any new replacement.

Well that might be your problem right there, a plastic head that old with that much use on it is bound to have a lot of wear and tear, and develop slop, that can easily contribute to blade tracking issues. Just a thought, maybe i am wrong altogether, but check all your ball links and be sure they are snug and not sloppy, as well as checking to see if the washout and swash bushings and bearings are all still slop free.

I would try swaping out the new Rx and TX with the old units to see if it still does it.
If it does, you know its the heli.
If it goes away, it MIGHT be just Tx set up.
(Could still be the heli if the DX7 has a hotter set up)
Good luck.
Let us know how you make out.

Brought her for a flight today, the blade track perfectly when it lift off the ground. I'm surprise, so after we reach home I try to spin her up around 55% throttle to c the blade, it is off. SO the conclusion is it will track when it is free in the air and it is above certain pitch & headspeed. Weird belt-cp.

Not necessarily a weird heli... The blades on my K2 only start to center up above the 50% throttle. Anything below that and they are off. I have a cnc head on my K2 and I fought many hours trying to get the thing to track straight thru the throttle range which just isn't possible, or at least not with mine. So I gave up trying. As long as it tracks true in the 50% plus is all that matters, aything below doesn't affect me. Unless al I ever do is let it spin up on the floor and never lift off.. LOL

Happy fly'n

I found that 50% is only the begining and run it all the way up to hover (75% stick) and do my tracking from there. Only reason is if you are going to switch to idle up you should be at 75% stick as that corresponds to where the stick will be at when in idle up for a smooth transition. That is when you switch to idle up the heli should barely move up or down drasticley. So you always do your tracking at a hover or flying headspeed or even a little more. This is because when you actually fly the headspeed increases over what you were running when it was fastened down (static runup) due to actually less of a load on the blades.

I have the purple cnc head and have never tried to do too much with the tracking until I went through the steps in Ray's authoritative DVD series. (This was brilliant BTW). But I now have big problems with tracking , a half turn can switch from red high by an inch and a half to blue high by an inch and a half. I have changed main and feathering shaft ,main gear, flybar, blades (balanced, checked for head balance. Could it just be that my head block is worn? Also I wasn't aware that there was a right and wrong way for thrust bearings to be inserted. My bird was sweet to fly before. Now its frustrating the crap out of me!!!