Yashica Lynx 14 shutter speed adjustment.

I have 2 Lynx 14 one is the original Lynx 14 and the other is the Lynx 14e. The 14e cosmetically not as good as the 14 and I do like the 14 better but the 14e shutter speed is reasonably accurate. The 14 however shutter speed is off at the 1/500 by almost 2 stops. I wonder how can I adjust the speed?

shutter speed is off

Click to expand...

Deterioration of the 'stop pad' can cause shutter speeds to be off.