KK vs a tricky play

[mtlchris]

guy is 42/21/1.5
but my set detector was going off here

Respectable fold or too nitty?

Full Tilt No-Limit Hold'em, $0.25 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

MP ($25.20)
Button ($17.60)
SB ($31.20)
BB ($63.90)
Hero ($41.45)

Preflop: Hero is UTG with K[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img]. SB posts a blind of $0.25.
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $1</font>, <font color="#666666">2 folds</font>, SB (poster) calls $0.75.

Flop: ($2) 2[img]/images/graemlins/heart.gif[/img], 9[img]/images/graemlins/club.gif[/img], 7[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $0.25</font>, <font color="#CC3333">Hero raises to $2</font>, <font color="#CC3333">SB raises to $4.25</font>, Hero calls $2.

Turn: ($10.25) T[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">SB bets $6.25</font>, Hero folds.

Final Pot: $10.25