Main and pilot air jet placement.........

Just for clarification purposes, since some of the Haynes and factory Yamaha manuals seem to be wrong, what follows is the proper placement/position of the Hitachi carb AIR jets----the ones up on the top of the carb body, under the top hat, under the diaphram, under the cover plate:

From the back (airbox) end of the carb moving forward, we have three threaded holes:

Hole #1 (furthest back, towards the air box): the cover plate retaining screw (not used on models that did not use the jet cover plate).

Hole #2 (center hole): the MAIN air jet, which is the smaller of these two air jets (smaller both in the numerically stamped size on top of the jet, and physically smaller as to the size of the tiny jet passage metering hole).

Hole #3 (furthest forward, toward the cylinder head): the PILOT air jet, which is the larger of these two air jets (larger both in the numerically stamped size on top of the jet, and physically larger as to the size of the jet passage metering hole).


Correct???

 

Looking straight down into the Carbs.
From the Air Box Side (Top)

Top Hole: Threaded for Special Fastener used for Cover Plate if so equiped.

Center Hole: Small Air Jet. Small number. Smaller metering port (as viewed looking at Port end; not slotted end). Factory = 80

Bottom Hole: Large Air Jet. Large number, Large metering port (as viewed looking at Port end; not slotted end). Factory = 225

 

Okay, thanks for the clarification Rick. BTW, the jets for a 650 Maxim are:

Main air jets = 50 (1980-83 650 Maxim, Midnight Maxin, Seca, and Euro)
Pilot air jets = 195 (1980-81 US 650 Maxim, 1982 650 Seca, and Euro)
Pilot air jets = 205 (1982-83 Maxim)


I think the 80/225 jets you mentioned are for 1982 750 Maxim and 1981-83 750 Seca models.

The 1983 750 Maxim used 80/195 jets.....

And rounding out the field, the Hitachi-equipped XJ700's used 70/210 jets.

 

Very helpful. Thank you.