How to reajust the allen's screw / motor ajustment
 

I put out the plate under the pistol grip of my AEG (ICS MP5A4), you know the plate with the allen's screw where you can adjust the motor... I have had a wiring job to do and now I need to put that in place, but I unscrew the hexagon screw (yeah I know I shouldn't, but). Somebody have an idea how to reinstall the screw because I need the perfect tension, not enough and the motor will push too hard on the gears and I'd probably ruin the gears, and too much isn't good also...

Any idea ?

Can only adjust it for sound, tighten it until the gears start to whine, then back it off a turn so you get the sound of the piston hitting and as little gear whine as you can. There's really no tricks to it, just a matter of cycling the gun and tweaking.