Instructions.

First
Squirt carburetor cleaner in the perifria of the jet so it will soak the jet's o-ring and any corrosion or varnish. This soaking should be nursed every 5 minutes or so. After After about 10 minutes try to GRAB the large diameters of the jets with a SHARP pair of wire cutters and twist the jets in their seats. DO NOT TRY TO REMOVE. You are just checking for their freedom of movement. If it is still snug keep squirting to break down the rubber and varnish. When it finally frees up that is great but chances are that the jets WILL NOT come out. They will only rotate.

Second
Use a hacksaw blade and at a slight downward angle saw using the blade only for better control into the jet and carb body till there is enough area to grab with the wire cutters. After sawing a groove on one side rotate the jet 180 degrees and groove the other side. Give the area another squirt to clean out the metal shavings and use the wire cutters with the jaws set in the freshly cut grooves. Pry out the jets. They will come right out. Even though the jets and carb bodies will not be perfect any more they will still function as designed and will perform no different.

As an option you could use a drill and chuck to grab the jet if you are careful and have a good grip, but if you don't do it just right you may damage the jet.

After cleaning the carbs you have the issue of parts. The gaskets can be reused if they were disassembled with a razor blade. The float valve seats can be reused as they are brass and the float valves are rubber.

The float valves (though exact replacements not available) are K&L part #18-8943 (they are slightly longer but work) and can be purchased at www.usedmotorcycleparts.com for $7.95 each.

The float valve filters can be removed if no good and their function replaced with inline fuel filters mounted on the hose.

Orings:

Go to www.mcmaster.com and order the following to build a rebuild kit for your hitachi's

For the air screws:
1 PK 9452K15 Buna-N O-Ring As568A Dash No. 007 $2.17

For the jets and float seat:
1 PK 9452K16 Buna-N O-Ring As568A Dash No. 008 $2.17

For the Fuel Tees:
1 PK 9452K18 Buna-N O-Ring As568A Dash No. 009 $2.17

These are bags of 100, so you see that for $10 you can get all the o-rings you need for a lifetime of hitachi rebuilds. You can also go to any autoparts store and get these. The info on #'s 7,8,9 follow:

#7
System of Measurement: Inch
AS568A Dash Number: 7
Inside Diameter: 5/32"
Outside Diameter: 9/32"
Width: 1/16"
Type: Buna-N
Use: Air Screws
Qty per bank of carbs: 3

#8
System of Measurement: Inch
AS568A Dash Number: 8
Inside Diameter: 3/16"
Outside Diameter: 5/16"
Width: 1/16"
Type: Buna-N
Use: Float Seat, Jets
Qty per bank of carbs: Float Seats (3), Jets (9), total 12

#9
System of Measurement: Inch
AS568A Dash Number: 9
Inside Diameter: 7/32"
Outside Diameter: 11/32"
Width: 1/16"
Type: Buna-N
Use: Fuel Tees
Qty per bank of carbs: 3

Air screws are not (as far as I have found) replaceable. Be careful after disassembly as the top body has them in there and are hidden under a brass plug that can be drilled out. Also there is a rubber o-ring on it and when you soak it in carb cleaner you will ruin that o-ring unless you drill out the brass plug. Also it bends easy if not removed and handled at all roughly.

All other parts are not subject to wear or damage unless you do not rebuild the carbs properly.

Happy Carb Cleaning!