"Bobbling" hammers on a new Yamaha U3. ( Please help! )

[Richard Brekne]

Greg Newell wrote:

> Cy,
>         I'm entering this late but, is there a chance that the jack is 
> dragging on the let off rail. If the rail is too close this can happen 
> as the jack pops out from under the butt.
>
> Greg Newell
>
Yep Greg.  Thats another one of those not friction issues I first 
mentioned.  Most noticeable on softer play and with stop felt that is 
not really all that compressed.

Course all these kinds of causes should be checked after you have first 
made sure the basic regulation is too specs, and that you dont have any 
of the kinds of problems with flawed geometry that have been tossed around.

That said... I find that upright hammer bobbling most often falls into 
this kind of problem category..... something inhibiting the jack itself 
from that last little bit of travel.  So it could be that Thumpy has 
found his problem..... if the sharp edge is hanging up on the butt 
leather.  But I'd make sure and check both this that you mention, and 
the other such causes mentioned so far.

Cheers
RicB