Anywhere from 2.5 to 4.5mph, really depends on losses and conditions. A properly tuned FD70/75 will cut beans at like 7+mph in good conditions if you really wanted to push it, but the number one thing for improving yield is slowing down the combine!
Cutting against the ground in really wet shitty conditions will expose every flaw in your header setup. We have some heavy sticky clay soils and do a ton of soybeans every year so this is what I've learned over the last 5 years with 40'macdon FD series headers.
Wing balance needs to be set as close to perfect as you can, or very slightly biased to smile. As mud builds up the wings get heavier, this will give you more margin of error and hopefully reduce dragging at the ends.
Wing float around 1-1.25 on the float wrench. Keep it as light as you can without the wing wanting to drift upwards into smile, and so that it wants to rise up over mud instead of pushing.
Cutterbar poly should be in good shape all along the header.
Completely remove all skid shoes on the wings, including the bracket that holds the outermost skid. Mud builds up on top and packs against the draper, which pulls it in.
Center skid shoes set to either hole 2 or 3 depending on how bad it drags. This will allow the autofloat to begin working sooner as it gives a lower point of contact for the center section, which will allow you to run a lighter float setting.
Autofloat! Make sure you have it and that you've done any calibrations, run as light as you can. Set it so raise speed is nearly maxed and lowering speed is almost minimum. Response time/delay to minimum.
Adjust the float cable on the slides at the front of the float control box so there is no slack at rest, or even slightly pretension the cable. This will make the potentiometer more responsive to small movements and thus make the computer react faster.
Adjust the draper seal all the way along the cutterbar so that the draper edge is slightly deflected. This will help keep mud out from inside the drapers. At most you want a credit card gap.
Put on fresh knives to reduce dragging when trying to cut tough stalks. We usually switch ours out every 1000ac of cutting per head anyways.
Make sure the bottom belly pan on the adapter doesn't drag, sometimes one of the arms gets bent down and will push mud.
Last edited by Slashnburn2; 09-23-2017 at 11:17 PM.