Your bike has two of the silver can flasher relays; one controls the 4 way signals, the other the turn signals. The front bulbs will be #1157 dual filament bulbs, and the rear ones will be #1156. It's possible the turn signal flasher is failing, but new bulbs all the way around should help in troubleshooting.
I'd open up the turn signal housings, looking for loose ground wires & possible corroded connections.
Color Codes On Most Kawasaki’s (written for 1980’s bikes)
HEADLIGHT
RED with BLACK stripe, High Beam.
RED with YELLOW stripe, Low Beam.
BLACK with YELLOW stripe, the ground circuit.
BRAKE/TAIL LIGHT Can be an # 1157 dual filament bulb
RED, Running or Tail Light.
BLUE,(sometimes with a Red stripe) Brake Light Circuit.
BLACK with YELLOW stripe, the ground circuit.
LEFT FRONT TURN SIGNAL,Can be an #1157 dual filament bulb
GREEN, Left front turn signal circuit.
BLUE, Left front running light circuit.
BLACK with YELLOW stripe, the ground circuit.
RIGHT FRONT TURN SIGNAL,Can be an # 1157 dual filament bulb
GREY, Right front turn signal circuit.
BLUE, Right front running light circuit.
BLACK with YELLOW stripe, the ground circuit.
LEFT REAR TURN SIGNAL,Can be an #1156 single filament bulb
GREEN, Left rear turn signal circuit.
BLACK with YELLOW stripe, the ground circuit.
RIGHT REAR TURN SIGNAL,Can be an #1156 single filament bulb
GREY, Right rear turn signal circuit.
BLACK with YELLOW stripe, the ground circuit.
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
