What was found
CREW REPORTED LIGHT HAZE AND BURNING ODOR IN FORWARD CABIN WITH FIRST CLASS LAVATORY SMOKE DETECTOR SOUNDING DURING CLIMBOUT. CREW REDUCED POWER AND HAZE/ODOR DISSIPATED. PROBLEM RETURNED WITH POWER RE-APPLIED. THE ACFT WAS RETURNED TO DEPARTURE. MAINTENANCE INSPECTED BOTH ENGINE INLETS, EXHAUST, AND UNDER COWLING FOR OIL LEAKS, NONE FOUND. INSPECTED GEAR, FLAPS, SPOILERS, TAIL SECTION, THRUST REVERSER CONTROL VALVES FOR HYDRAULIC LEAKS, NONE FOUND. ACCOMPLISHED FULL DUCT BURN OUT. APU INLET BOX REMOVED, CLEANED, AND RE-INSTALLED.