50PL 66 in SB hits turn set on straightening board 3 way

[Antinome]

Full Tilt Poker, $0.25/$0.50 PL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

BB: $60
UTG: $15.30
MP: $18.80
CO: $27.25
BTN: $48.50
Hero (SB): $58.65

Pre-Flop: 6[img]/images/graemlins/club.gif[/img] 6[img]/images/graemlins/heart.gif[/img] dealt to Hero (SB)
UTG folds, <font color="red">MP raises to $1</font>, 2 folds, Hero calls $0.75, BB calls $0.50

Flop: ($3) K[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/spade.gif[/img] (3 Players)
Hero checks, BB checks, MP checks

Turn: ($3) 6[img]/images/graemlins/diamond.gif[/img] (3 Players)
<font color="red">Hero bets $2</font>, BB calls $2, <font color="red">MP raises to $6.50</font>, Hero ...

I've been caught stealing orphan pots with air twice recently, and the whole table is probably pretty annoyed that I keep bumping up their dopey minraises and limps. No strong reads on villain, though he definitely isn't tight or aggressive normally. The minraise preflop is his standard raise, it doesn't mean a big pair, a small PP, or anything else necessarily.

Note- I'm absolutely not considering folding here- only trying to decide if I can or should raise.