What was found
DURING TAKEOFF ROLL, F/O CALLED 80KNOTS, CAPTAIN SAW 50 KNOTS - 30 KNOT AIRSPEED DIFFERENCE. AT100 KNOTS ON F/O AIRSPEED, CAPTAIN SAW 70 KNOTS. REJECTED THE TAKOFF AND COMPLIED WITH QRH PURGED CAPTAINS PITOT LINES AND PROBE IAW AMM 34-10-00-03 FOUND NO BLOCKAGE. PERFORMED LEAK CHECK OF BOTH CAPTAIN`S AND F/OS PITOT SYSTEMS AND FOUND CAPTAIN`S SIDE LEAKING. ISOLATED LEAK TO PITOT DRAIN IN NOSE WHEEL WELL NOT FULLY SEATED. PERFORMED PITOT DRAIN SERVICING IAW AMM 12-24-34. PERFORMED SECOND LEAK CHECKED AND PERFORMED OPS CHECKS IAW AMM 34-10-00-05-0, OPS CHECKED GOOD. LEAK CHECKED GOOD.