Tail vibration in R90SE

[siavreg]

I have researched every thread possible in this forum and have done them all or checked what I needed to check as per suggestions and I still have the tail vibration.
A little history : This heli was flying perfect, I've never crashed it, never landed it hard, same fuel from day one, changed the plug OS#8.
This has started to show up in the last month and seems to be getting worse, now having said this you would think something is wearing out? But I'm at a loss for what it can be.
If there is something that I'm over looking or something you guys can suggest please do so as I'm getting frustrated and hardly want to fly it anymore because of it.
I want this issue fixed so I can go back to flying the s@*T out of it, cause it was an awesome machine before this issue.

Help please :(

[vandelescrow]

Vibrating up and down? head speed too low.
vibrating side to side? gyro gain to high, length from center of servo to ball link on tail servo too short, tail blades too tight, loose bolt/nut holding tail blade grip on, play in tail assembly including gear box, lube tail shaft, tail assembly not balenced.

Just some ideas to look at, hope they help.

[Lota Fun R]

Since it is a problem that has developed over time, my thoughts are that something is coming loose. Take it apart and you'll likely find the problem.

I have a tail drive shaft that is new and one end is not true, I'll have to replace it before my Rappy goes back up again.

It's a lot cheaper to fix a problem than fix the whole heli.

[siavreg]

I have taken the tail end apart and do not see anything grossly out of place. Now when I move the tail by hand and watch up by the main rotor there seems to be a fair bit of play before the main drive catches to start turning the head. Is this normal?
I will try and see the main rotor head speed as I have not checked it lately?
I guess one other question to go with the thought above, how much play should there be in the tail drive assembly?
Thanks for the help.

[siavreg]

Well I went to try and figure this out at the field. I'm starting to think the low headspeed thing might be it because it is "Vibrating up and down? head speed too low" Now my question is this.
When the heli is running it is spitting out copious amounts of fuel. I thought it might be coming from the head being loose, its not. Glow plug loose, Its not. I put all the needle valves settings back to the original settings? Can this be the issue. I have TONS of smoke. I know you can't always go on this but this seems to be a huge amount. Can anyone tell me there carb settings on the YS91ST motor so i can set it up properly. Also could there be something in the carb or pump that is keeping it open and getting to much fuel?
Thanks

[vandelescrow]

air fuel mix could be causeing the problem. When you notice the vibration in the tail, do you hear the engine surging? Engine is probably too rich. Sorry, I can't tell you where my needles are, I do not have the ear for tuning engines and depend on a local expert.

[Lota Fun R]

Do some research on YOUR engine. If it's dripping a pool of fuel out after flight, it's too rich. You'll need to get all you needles set properly, you can lean out the main a bit and be ok, don't lean it out too much without richening your lower needle/s, It may be lean on the low and way rich on top or vice versa? Too many variables to give too specific advice here.

[siavreg]

I think the settings were way to rich. I've adjusted according to manual and will test today or tomorrow. I'll be back if it doesn't change anything :)
Thanks for the help so far.

[siavreg]

Just a quick note to let people know why my tail was vibrating. After many flights on this machine the tail pitch slider must have started to come loose and screw itself in causing the two bearings to become compressed to such a point that they started to bind. I've since loosened off this brass slider and all is well in the world.
Thanks everyone for the help and sorry for taking so long to post why?
Cheers