I have recently rebuilt my v2 from a crash and having some trouble with the tail. I have a futaba 401 and 9257 tail servo. Its flyable but I don,t think its right. In a hover ,If i turn the tail to the left say 30 degrees: It will come back right about one to two inches before it locks in to its position. Its the same if I move the tail to the right , It will came back left about one to two inches.I have tryed to increase the gyro sensitivity on the radio , it just couses hunting to acure with no help to the problem. At first I thought the gyro was not homming properly, so to test this I trimmed the tail hard left . I then turned the heading on and off three times to rehome the gyro , seems to be homing just fine.I have also ,one time tryied incressing the delay from zero to about 20% with no results. I don't think I had this problem before the crash ,but not 100% sure. This is not normal operation is it?

No, that is not normal.
question 1: are the servo gears damaged?
question 2: does the servo appear to respond normally, if hooked up directly to the receiver - on a different channel?
question 3: is the mounting for the 401 gyro in good shape i.e. not damaged / ripped?
If all of the above are OK, I'd suspect the gyro itself is damaged.

Thank You for your responce. The tail had vary little damage ,but I did replace the tail boom becouse it had a little bend in it.The servo and the tail seem to work vary smooth. Im thinking that maybe the servo is over traveling the gyro, but not sure what to do about it? The limet switch is at its lowest point 60 and the linkage is set on the servo horn on the second hole from the tip.

Move the linkage in and up the limit

It did not work,by the time I was done; I had the limit all the way up and the linkage on the servo at the lowest hole. It did hower make the bounce alot smother ,but still travels about one to two inches back before locking in. Still fustrated, but appreciate the help.

What does that even mean?, well don't bother answering its impossible the servo doesn't drive the gyro.


Read the above and answer the questions I think your answer lies within the answer, or that your gyro is damaged.

I Never said that the servo drives the gyro! As a newbie what it appeared to me was,the gyro was locking in HH before the servo finshed moveing the tail, which would make the tail come back to the HH position. As stated before ,the tail had vary little damage in the crash. The servo runs smooth with or with out the linkage hooked up or on anther channel. I did not remove the cover and look at the gears becouse it seemed fine. The 401 appears fine and is mounted well to the bottom of the heli. I fly this heli as is with out any other issues. The tail wag is consistent not sporadic ,so I belive the 401 is not damaged.

When you rebuilt the heli did you check the one way bearing to make sure it was working properly? I don't think that could be the problem but we need more info to help find a solution.

Yes , Athough I belive its ok; I replaced it along with the new rotor head and main shaft. Main barrings was also replaced and belt. I had a landing that was a little to hard and the tail was not tight enough. It slid forword and on my next flight the belt jumped track ,bound and broke. After replacing the main shaft and flybar It had a nasty wine to it,So I replaced the whole rotor head. It still had the wine ,the only thing left was the motor. I replaced that and sure enough that was it. Im just trying to fill you in on all the changes since the crash. Also I changed the pitch from 11% to 10%. I had the thought once that maybe the les pitch could be the problem. Thinking maybe the heli was at a higher rpm at hover then before. So I changed that back with no help to the problem.I have also noticed that my trex on the G3.5 also has a little tail wag ,not as bad as mine but its there.

The only thing I can contribute is maybe there is a vibration somewhere. Maybe in the main rotor or tail rotor. From the pictures I didn't see any obvious tape or anything on the main blades. Who knows. That might alter the function of the gyro.

I have no idea if you have considered this but I read that there are several servos listed that need to be have a step down to 5.1v when using the GY401. I don't remember where I read it but I do remember that my servo (Futaba S3154) was mentioned. I believe your servo is one of them as well. They say that running 6.0v to those servos could cause a burn out or excessive wear. So I have grounded my heli with the S3154 until I get another Futaba 9650. Good luck.