Mix salt with both flours and place on a large cutting board, or in a large bowl.
Make a well in the center of the flour using the bottom of a small bowl or a large spoon.
Start mixing the two whole eggs and 2 egg yolks into the flour with a fork, bringing more and more flour into the mixture as you go. If you need extra egg yolks, add them one at a time, until you arrive at a workable dough - not too dry or too sticky.
When your dough feels workable, gather it into a ball. The dough will be fairly stiff at this point.
Knead dough for 4-5 minutes, dusting with flour as needed.
Divide the dough in half and form each half into a disc. Wrap the dough discs in plastic wrap.
Refrigerate dough until you are ready to roll and cut the pasta.
When this time comes, take dough from the refrigerator and let it sit on the counter for about 10 minutes before rolling it out.
Now, using your pasta machine, roll the dough to your desired thickness and cut into fettuccine noodles with the fettuccine accessory, or with a sharp knife.
String the pasta up on the pasta rack and allow to dry for at least two hours before cooking it.