'78 KZ400 Crackshaft Bolt Removal

I'm trying to remove the clutch cover on my bike and I can not get the crankshaft bolt loose. I am holding the 17mm bolt still and trying to loosen the 13mm bolt so I can remove the timing assembly but I can not get the bolt loose for anything. Am I doing something wrong here? Does anyone have any advice on how to do this? I hate to take it to the shop for this but I am about to that point. I appreciate any advice.

I'm not familiar with the KZ400, but on a 650 the center bolt on the end off the crankshaft is a normal thread, so does come off counter clockwise.
Long wrenches may help, having more leverage.
Maybe a past owner used lock-tite on it. May need to heat it up then to loosen it.