Bigger Carb

I DO A LOT OF CROSSCOUNTRY AND ENDURO EVENTS IN HEAVY SAND TRAILS.THE TIGHT FOREST SECTIONS ARE OK BUT THE STEEP UPHILL HEAVY SANDY AREAS CAN BE A CHALLENGE FOR THE OLD GIRL.THOUGHT I MIGHT PUT THE KDX 200 CARB ON PWK 35 BUT ARE HAVING DIFFICULTY SOURCING ONE.DID FIND A 1989 KX 125 36 MILL CARB.WOULD THIS BE OK?OR AM I GOING TO BIG? WOULD IT FIT?. OR WOULD I KILL THE TORQUE?
THANKS