Stall warning

I have a question about a 78 Supercub with, what I believe to be, a factory stall warning horn. The horn will start hollering while in a 45 degree bank @ 80 kts. I was wondering how the mechanism is adjusted and calibrated to give the proper stall speed indication? Is there a measurment that can be taken to get the proper adjustment?

some have a slot at the screws that you can loosen and then slide the stall warning, but most, you just bend the tab sticking out down a little to lower the speed when it comes on. Trial and error is best.