Performing airtight test in my D-180

[sonexbuilder553]

Hi all in the forum, and sorry for my english.
I have just installed the pitot lines in my Sonex-Dinon-180, and when I performed an airtight test in the presure line with a small air filled syringe (the airtight test was OK), I observed that the horizon line of the attitude indictor move piching up when the indicated speed was growing up ad piching down when the presure was relased.Can any body the relation of the indicated speed and attitud indicator?

Thanks to all, Miguel

 

[Etienne]

Check this out:
http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1238468791/1#1