starting to get a tail wag? possibly from motor bearings?

[concept1]

i have been flying my 500 all spring and really like this heli. But for the last few days I am getting a very fast tail wag, I am using a DX7 and have my gain dropped to 30% using a 401. no crashes and nothing has been changed on this heli! at 30% the tail does not hold solid, but if I raise the gain it really wags bad but holds great! I pulled the motor to change pinions and looks like my bearings maybe starting to go, the motor does not whine but I suspect the bearings are going, hard to totally tell since the motor doesn't spin free do to the magnetics! I have replaced the foam tape on the gyro and even doubled it, now it is better but it is now speratic. and happens occasionally. Head and tail are balanced and their are no vibs in the heli, it has always been super smooth untill a few weeks ago and it seems to be getting worse. all other bearings seem smooth. has anyone had motor bearing issues that gave them gyro troubles? others I have talked to have had motor bearings go but they have made noise, and my motor is still quiet. when I get the time I hope to pull the motor from my buddies and try it but any other ideas?

[727driver]

Check all the mechanics in the tail drive system. I had exactly the same problem as you and it turned out to be a loose mount for the tail pitch control arm. Tightened everything up and it was good as new!

[vlanz]

maybe your batteries are getting old and your arent getting good head speed?

[sigpe57]

"Check all the mechanics in the tail drive system. I"

I agree. It's usually the most basic answer. You should start with the most basic troubleshooting first, like a loose screw. Leave the electronic and gyro trouble-shooting last.

[concept1]

been through all that, everything is tight and balanced, I borrowed my buddies motor and will swap it out hopefully tonight and see what happens!

[727driver]

Let us know what solves the problem.

[concept1]

so far nothing, I swapped out motors and still their, I went thru pretty much the whole heli and didn't find anything else worn, head, grips, tail etc... next step is to swap out the Esc, then the tail servo and the gyro last. it is more sparatic now so i am wondering if it could possibly be from the esc/bec. I have another esc so thats a easy change. but I am convinced it is not Mechanical.

[sllimg]

I had the exact same problem with my 450 Pro. Very frustrating when you can't find the problem! A friend who had been through the same thing told me his problem was a bearing that was seizing up. He oiled his bearings and it fixed the problem. Sure enough, after oiling all the bearing, the tail was rock solid.....no wag, no vibration....good as new! I think the problem was one of the bearings in the tail, but I'm not sure because I just oiled all of them and the problem was gone. In hindsight, I wish I would have isolated the problem so I could have replaced the bearing, but I haven't had any problems since. I've heard different things on oiling bearings, but after having this problem, I oil my bearings regularly.

[JaggedEdge]

Originally Posted by vlanz

maybe your batteries are getting old and your arent getting good head speed?

that was my first thought.

[sllimg]

Any update? I'd be interested to know what you find.

[concept1]

didn't have time to fly it , so no changes yet. I have 3 A123 packs and all do the same so not likley a bad pack, I am running the align esc and the bec is set to 6v, I will swap it out next. it could be the bec just not holding good voltage but on 7s A123 that shouldn't be a problem.