Valve cover gap MUCH LESS than spec

Roger Lee wrote:

You don't want the valve covers to touch and rub from vibration. You MIGHT be able to loosen the valve cover a tad, but you most need to loosen the head nuts to move the cylinder the proper amount. Roughly the space of a business card.It's pretty easy to do and hard to mess up.

Hi Roger,

My  new Rotax 912ULS (3.9hrs) has a Valve Cover (Rocker Box) clearance of about the thickness of a sheet of A4 paper. Would you consider this to be okay?

What's A4 paper?  ?

I’d loosen both cover screws and place a credit card in between the covers before tightening.

Tyler Hathaway wrote:

As to 3.  I doubt the valve covers the source of the noises you describe. 

Have you had any work done on your oil system?

How's your friction torque?

Friction torque recently tested by an iRMT.  I just checked prop pitch, prop track, carb balance, exhaust system fit, and all but 1 of the engine mount bolts.  The final bolt (engine top right) has no torque stripe on it, and I can't get a hex driver in there without removal of things beyond my comfort level.  I'll have iRMT do that this week, along with the valve covers, and I'll get his feedback on the noise/vibration. 

Roger Lee wrote:

You don't want the valve covers to touch and rub from vibration. You MIGHT be able to loosen the valve cover a tad, but you most need to loosen the head nuts to move the cylinder the proper amount. Roughly the space of a business card.It's pretty easy to do and hard to mess up.

Loosening the head nuts and moving the cylinder sounds terrifying.  I would not have thought lateral movement possible, and it seems like a new head gasket would be mandatory. In any case, thanks for the input.  I'll bring it up with my mechanic.