bluffing missed draw

.25/.50 ring game.
This was my first orbit. People are generally weak/passive on these tables.

Hero (on the button): A /images/graemlins/diamond.gif, 2 /images/graemlins/diamond.gif

Flop (Board: 10 /images/graemlins/heart.gif, 8 /images/graemlins/diamond.gif, K /images/graemlins/diamond.gif):
Nyanyo: Bet 0.50
clabber: Raise 1.00
Hero: Call 1.00
Nyanyo: Raise 1.50
clabber: Call 1.50
Hero: Call 1.50 (I love those gayraises..........)

Turn (Board: 10 /images/graemlins/heart.gif, 8 /images/graemlins/diamond.gif, K /images/graemlins/diamond.gif, Q /images/graemlins/spade.gif):

Nyanyo: Bet 3.00
clabber: Call 3.00
Hero: Call 3.00

River (Board: 10 /images/graemlins/heart.gif, 8 /images/graemlins/diamond.gif, K /images/graemlins/diamond.gif, Q /images/graemlins/spade.gif, 9 /images/graemlins/heart.gif):
Nyanyo: Check
clabber: Check
Hero: Bet 6.50

the pot was 15 or so if I recall correctly, so I figured this play has to work just 1/3 of the time right ? I usually nut peddle on these tables so I'm not use to making these kind of moves, but they showed a lot of weakness on the river.