valver airbox diameter of inlet hole

[richyb]

hey does anyone know the diameter of the inlet hole at the bottom of the standard airbox for the valver please cos want to add a longer inlet pipe and need to know what size pipe to order 50mm,65mm, 75mm or 100mm.want to get this will it work has any1 done it?

http://www.2modified.com/-c-21_1955.html

cheers rich