Gsx-R 1000 radiator filler neck

I damaged the radiator filler neck in a crash on my 06 Gsx-R 1000 and I need a replacement filler neck. I've got a friend who owns a shop that builds dirt track cars that is going to weld it on for me. Anyone have any info on what size I need to buy? I would measure it but its mangled and distorted. Any info is appreciated.

 

as long as it's not bent/creased it most likely can be fixed, you gotta have some patience Smitty

 

I thought about heating it and trying to straighten it but wasn't sure it was worth trying.

 

I cut one off of an old ex500 and had my buddy weld it on my R6 a couple years back. Worked great.