Hey Joe 
Great find!
They offer the '86 TRX Intake boot too!
https://qvmx.net/product/honda-trx25r-86-87-airbox-boot/
I remember Bill. I worked with him to produce the first version of that 86 boot. The prototype polyurethane wasn't very flexible if I remebmer right, so using it with a larger carb ws going to take another version.
From that pic, it looks like he's extended the length a litlte too maybe.
