RE: Welcome to Club SAITO !
[b]IronCross:
Sorry, intended to include this last time.
The 10mm thread is a few thousandths of an inch larger than 3/8", the 12mm is a hair smaller than 1/2", and the 14mm is 9/16" diameter. Hope this helps your ID of the pipes.
Bill.
PS: Thanks for the kind words. wr.
EDIT: And the plastic back plates do not help to keep the intake pipes held firmly. The later ones are better, but the pipes are still prone to vibrate and destroy the upper seal. wr.