Cr 500 wheel help

Nope. The axle is smaller for the 500 wheels.

Flextape it.

Buellar...buellar...buellar
I know there is 500 dudes on here, I figured the axle was smaller but would a collar of some sorts work.. I can’t be the first dude to try this

You can get the wheel spacers made but you have to run the 450 rear brakes because the rotor is a different size.

A bearing swap would solve the axle issue, then deal with the spacer and brake issue, as mentioned. Not complicated, just some legwork involved. Good luck.

Better make sure they are from a 2012 CRF450. I saw in the other forum where you said 12-14. The rear wheel was changed in 2013. The hub physically places the sprocket 3mm further outboard. There's really nothing you can do to work around that either.