Okay, what has it been? About 2 weeks?
A few notes:
Adjustable center pin - loose and might back off or fall out? No, that is by design. Same as the Ithaka center pin. it can be backed out. You install the tank and the screw makes contact, but allows the tank to continue turning to seat on the mod. Can't fall out, mod is under it.
Air Flow/Whistle - Center shaft alignment? Not hardly. The center slot is to direct incoming air up through the chimney. The area where the slot sits is much larger than the upper and lower bore. Plenty of room for air to flow around and up.
*don't worry, I had the same thought before a full tear down and inspection.
What do you mean by this center pin info; I though it was just a 2nd screw that covers the center post screw?
And the whistle, are you saying that the slot in the post and the air hole don't have to be aligned?
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