IMO The easiest way to set the needle height is; Turn the mixture screws all the way up, keeping track of the number of turns. Remove the piston, loosen the needle set screw, pull the needle out about an 1/8", tighten the set screw just until the needle won't fall out. Install the piston & chamber, using a pencil or other soft item push the piston down using the oil access hole on top. The piston should move down about 1/8". This will bottom out the needle against the nozzle, which is the proper height. Remove the piston tighten the needle & reassemble. 

I follow the same basic procedure as Mark. I just use a straight edge across the needle shoulder and piston bottom to get the needles flush. Sometimes I'll use the edge of a Vernier caliper if I want to lean out the idle a bit by having the Needle shoulder protrude by about .020" from the Piston bottom.

Thanks guys, this info has been great!! Now i'm excited to rebuild the carbs! 

One tip, make 2 piles.  One for the front carb, the second for the back carb.  Make sure to keep those parts separate. 

 

a rebuild kit from ztherapy is cheap and well worth it. the floats are the most critical initial adjustment, as they set the fuel level at the nozzles. the float needle valves can be finicky so replacement is the ticket - they come w/the kit.

 

you'll be taking the float chamber tops off a bunch of times to get them adjusted - stick the float chamber gaskets to the lids w/some gasket cement so they don't pringle and become impossible to align

When you order the kits, assuming they're coming from ZTherapy, get the "SUs only" DVD too. The knowledge shared in this DVD will take any guess work out of the rebuild. 

Here's my approach on adjusting the floats.

 

 

http://jarvas240z.blogspot.com/2013/06/carb-float-levels-sightglass.html

When you order the kits, assuming they're coming from ZTherapy, get the "SUs only" DVD too. The knowledge shared in this DVD will take any guess work out of the rebuild. 

Absolutely!

 

The Just SUs DVD came with my rebuild kits, $180 I believe.  Well worth it, new nozzles and hoses are hard to find.  The DVD talks about Grose Valves with a ball instead of the pins but they no longer make those so you get the valves with pins.  It's kind of funny hearing him talk about how much better the Grose Valves are compared to the pins.  No big deal though.

Here's my approach on adjusting the floats.

 

 

http://jarvas240z.blogspot.com/2013/06/carb-float-levels-sightglass.html

Thanks for that Dave.

 

I have my carbs and intake screwed to the wall above my work bench.  I am going to set the levels the best I can before putting them on the car.  I need all the information I can get. 

Thanks everyone for the advice. I ordered a japanese kit from zcardepot. I should have ordered the dvd from Ztherapy but was in a rush.

I do have a few questions. What is the procedure to temove each carb from the thottle, how do I separate the float bowl from the main carb body and how do I adjust the linkages?

Thanks!

There's tons of stuff on youtube.com about SUs.  They really are simple.

 

Take the 8 nuts off the intake studs, 4 per carb, and the whole assembly will slide right off.  The only connections are the fuel lines and the vacuum advance tube on the front carb.

 

Take a bunch of pictures as you disassemble them.  Two separate piles, they are the same but opposite like looking in a mirror. 

IMO It's not necessary to separate the float bowl from the body unless it's leaking fuel from the connection.