RE: Welcome to Club SAITO !
Doug:
The only way I've been able to assemble the intake pipe is to put the 0-ring in the recess in the head, then work the pipe in with the aluminum ring on the pipe. Never been able to put the o-ring on the pipe first.
I bought a fist full of OS "F" plugs a few yes rs ago (got a good price) and I'm still using that stock. Horizon sent me a couple "Saito" plugs to try, they work fine. Next purchase will be the Saito plugs. It's been too long since I've run anything else so I really can't comment on them. You know the old bit, "If it aint broke..."
Bill.