VF500 carb and boot differences

I understand the VF500 84/85 carbs are different throat sizes from the 86 (32mm and 30mm respectively). The only area I can see as being measurable is the throat that is after the butterfly, the part that fits into the carb boot and then into the head. Is this the right place to measure?

If so I have 84/85 carbs on my 86 VF500, which I understand is a common 'upgrade'.

Which might make replacing the carb boots easier as those for the 86 are impossible to find, 84/85's plentiful new or NOS and cheap.

However are the carb boots different on the cylinder head side? I know there are two different part #'s which would imply the carb OD where it fits into the boot is different but maybe not on the head side. Are the two boots interchangeable? Is the boss on the cylinder head different? The boss that accepts the boot on my cylinder head measures 1.5" OD at the upper rim (the area that the boot first touches when installing).


Tom Duncan