Vibe log help needed...

[ericbuzz]

Hoping you guys could help out. Attached is a screen shot of my vibe log. I'm seeing the vibes in the up/down acceleration. What does that correlate to? I'm seeing the highest spike in the motor RPM range.
This is on my Goblin 500.


Any help is appericated!




-Eric

[georgi UK]

=] upload the full log please, screen-shots can be misleading. looks like motor bounce which is being transmitted to the tail drive via the maingear?

[ericbuzz]

Here you go... Renamed extension to .txt

thanks georgi!

-eric

[georgi UK]

=] check the motor for shaft end float, damaged bearing track maybe? when that is sorted do a bench vibe log without mains and tails, with a towel under the skids to prevent feedback and we can re-look at the tail vibe, it looks like it's out of balance, blades off will determine this.

[ericbuzz]

what exactly do you mean by shaft end float?

[georgi UK]

=] the motor stator is moving up/down, bouncing as it rotates. this happens if the bearings allow such movement or a chipped bearing track would do the same thing. the inner race should support the stator with zero end float.

you check this by looking for any pinion movement or notches as you rotate it.