Illinois is horrible. They dont recognize any concealed carry, obviously. I own property there so I read up on how to transport firearms. They want your guns to be unloaded, in a case. Also you cant be within reach of any ammo. They prefer that you take the gun apart too. This could be hard to do on a bike. I would put ammo and the barrel in one saddle bag and the rest of your gun in the other. Or if youre in a group, have one rider carry guns and another carry ammo. They really want you defenseless.
My dad was almost arrested in IL because he had an unloaded, uncased shotgun on the backseat of his truck. He didnt have any shells in the truck which is the only reason he wasnt arrested.
I should mention that somebody I know drives everywhere with a loaded .45 under his seat, and this includes IL. If you dont get pulled over and searched then it doesnt becomes an issue. However thats your decision to make.
Have fun on your trip.