I don't have a tilinko. Yes they are narrow bore.

I measured my Moldavian A kaval for Francis de Villiers here when he asked a few weeks ago. This is the email I sent him:

Moldvai kaval in A, one-piece elder, by Feri Szegercz from Georgheni, RomaniaNote the labium is on the LOWER side

overall length: 74.5 cmext dia: 26mmbore not very circular (done with 2 augers)int dia at bottom end: 16.2-16.9mmdia of block: 17.9mmlength of block: 21.9mmarea cut off block for windway: 1.12cm at mouth end, 0.7cm at labium endabout 1mm of chamfer at the windway endvoicing opening: 0.65cm long, 0.55cm wide, labium length: 2.0cmwall thickness at labium: 0.52cm one side, 0.47cm the otherlabium very slightly curved concentrically with the bore and slightly concave longitudinally, maybe 0.5mm each way

fingerhole centres from bottom:12.1cm14.8cm24.4cm28.3cm31.6cmfingerholes all 0.77cm long and 0.64cm wide except for the bottom one, about 1mm smaller all round

The "A" Kaval whistle plays these scale notes in the low octave: A B C D# E F 

Lungime de la vrana pana la capat: 72.3

Si – 16.7 %

Do – 20.5 %

Re# - 33.7 %

Mi – 39.1 %

Fa – 43.7 %