I give up. Throwing this out to the RC world as a last tidtch attempt for help. Managed to hover me 450 into a brick wall (long story). I have replaced the CF blades, the flybar, the tail rotor grips, the tail rotor cyclic control. Put her all back together and she shakes. Checked the flybar, its 100% even on each side. checked blade tracking...perfect. Went and put in a new mainshaft and spindle for and giggles. No bueno. Doesn't shake without the blades, with the blades I'm worried she's going to strike the rotors on the ground. once in the air you can plainly see the tail vibrating so something is out of whack. Any thoughts out there?

Could be a multitude of things. whats your head speed ? lets start there.

I presume you've done blade tracking?

Originally Posted by Hajile

I presume you've done blade tracking?

Yup, I use a system similar to what we use to calibrate our printers. take 1/16 inch tape and line the LE of the rotors. One blade has two lines. the other has one line that fits between the gap of the other two. adjust tracking so tht it looks like a solid line and its perfect. the vibe is most prominent during spool up, but at speed he tail fin is a blur so i iknow something is amiss, I'm just running out of parts to replace.

Did you make sure your blades were balanced? Could also be your head block, but you would see a visual wobble when the head spins.

http://www.amainhobbies.com/product_...or-Housing-Set

I just received the hex bolts for the tail holder in the mail so i finally put the 450 back together. Changed the feathering and main shaft but it was still vibrating really bad. Leveled the blades, tracking is perfect, it still wobbles. Then i had a thought and removed the blades and canopy and spooled it up while looking at it up close. The main gear was wobbling, apparently some of the teeth got shaved in the last crash.

I'm gonna have to take the head apart again to get at it I'm done for today, gonna go our and fly the GeniusCP. Try checking your main gear.

EDIT: Finally swapped main gear... YAY! Butter Smooth Spinup!!! Now i have to level the blades again

Originally Posted by RFDelie

Did you make sure your blades were balanced? Could also be your head block, but you would see a visual wobble when the head spins.

http://www.amainhobbies.com/product_...or-Housing-Set

I'm using carbon fiber blades. I thought they didnt need balancing.

yes u need balance them i got a set of radix frist set i didnt have to balance they cost more but they worth every penny

Found the issue. Apparently the $36 CF blades from horizon hobby that are "precision balanced" are not. Was about to give up on this bird when out of desperation we put the blades on a balancer at the LHS. It took two metal screws on the tip of the blade to make it balance. Hobby store folks were kind enough to give me a new set. She runs perfectly now. So just a word to the wise. those "balanced" Carbon Fiber blades are anything but.

Take of the rotor blades and spin it on the ground , does it vibrate ?
Take of the tail rotor blades , does it vibrate ?

This is the starting point ,

Find out where the vibration is coming from ..