help with swingarm

[quad2xtreme]

I have an aftermarket swingarm to go on my wife's Honda 450r that I believe is designed to use the Banshee chain guard that is located close to the rear sprocket. I am looking for an inside width measurement where it mounts between the two brackets. I just bought the JB guard but it is narrower than the brackets. I can shim it to fit but would like to avoid this.

Any help is greatly appreciated.

Thanks,

Jon