Just changed the tire on the front of a friend of mine's 750. After a little advice from another friend, we left the front end off the stand and broke torque on the pinch bolts and on the the right side axle nut. We then put it on the front stand. To get the axle out we used a that would fit into the left side of the axle. Once the correct size bolt is found add nuts so that you can use it to twist and pull the axle out. The key for us was putting a little bit of tape on the bolt head so it would grip the axle as we twisted and pulled. Here is a page from the service manual:
REMOVAL AND DISASSEMBLY
• Remove the brake calipers.
• Loosen two axle pinch bolts 1 on the right front fork leg.
• Remove the front axle bolt 2.
• Remove the under cowling. (8-5)
• Raise the front wheel off the ground and support the motorcycle
with a jack or a wooden block.
• Loosen two axle pinch bolts 3 on the left front fork leg.
• Draw out the front axle and remove the front wheel.
NOTE:
After removing the front wheel, fit the calipers temporarily to the
original positions.
• Remove the collar 4.
Do not operate the brake lever while removing the calipers.
Do not carry out the work with the motorcycle resting
on the side-stand. Do not support the motorcycle with
the exhaust pipe. Make sure that the motorcycle is
supported securely.