Tony,
I have the same set-up as you (XS, 912S, 21.5degrees) and have clocked up
150 hrs.
---From new I have had a vibration at 3000 rpm - not too bad but enough to
annoy!
The engine is smooth at all other settings and I have had the prop balanced
three times with no (or very slight) improvement.
One thing which does puzzle me, though - and no-one has been able to explain
(Skydrive included) - is that, while there is no appreciable mag drop at
either 4000 or at 2000 rpm, at 3000 there is a marked miss-fire on left mag
only and,of course, a vibration to match !
Could the problem be purely ignition related and not an imbalance ?
I would be very interested to hear what happens when you try a mag check at
your vibration rpm if you would be so kind.
Regards,
Ron Jones.
(XS, 359, G-RJWS)
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