I mean pump gas (91). If the head is "milled" for AVgas, and you are only getting 120psi there is something no adding up. Either the head was fucked up or your gauge is fucked up.
An extra inch of ground clearance is huge on a banshee. Figuring stock they are only like 5.3". IIRC going with a solid skid plate you lose clearance. The stock skid plate catches everything. The disc is nice.
The welded didn't get hot at all. Hold it on there a little longer and turn the amps up more. Get the juice flowing and get the welded to penetrate both the flywheel and puller good. Get it red hot.
you see the damage currently on the flywheel? ya, that happened from a jaw puller. never use a jaw puller to get a banshee flywheel off as it can cause the damage seen above.
One thing I would suggest is make sure your tires are balanced, and your axle is straight. Also, don't run knobbies. Another thing that might help is a steering damper and a sway bar.