anyone know how to separate a stubborn exhaust?

[fairpilot]

yea change the starter while you have it accessible. do you see any corrosion (eaten away edges on the manifold) that would let water in. Are you ready to start your yamaha repair shop yet Now we see why it cost so much at dealer.
Not sure what they do for the case, will be interesting to find out, wonder how the cracks got there to begin with.

 

[Cobra Jet Steering LLC]

If the bolts are the ones in the manifold, you can just cut off the heads and tap them out through the bottom, if you try going out the top you may bell out the bolt and make it harder to get out , you already know the bolts will go through the other way with no issue if the heads are cut off.