i thought i might post up something with what i have had to do with gx carbs in the past 6 months of screwing around with them
now as you know it is hard to find rebuild kits for these carbys not sure on the flat tops but defiantly for the round tops but a rebuild kit from the early roadster can be found easily and be adapted so here is what i had to do to adapt them
ok here the pics and show what i did as the needle and seats are slightly taller then the originals






as you can see i had to squash the lil piece of brass thingy
these kits can be found on ebay motors and they come with new larger needles maybe could be used on a hot motor that has gx carbs?
i used these ones
here
there are also these ones but i dont know if they will work and i havent tryed them
clicky

now dont know where to take the vac advance from? heres a pic to show where to take it from this is located under the front most carb


now here is another pic showing where the overflow is and the fuel in for these carbs some people have got confused when buying an incomplete setup that doesnt have all the fuel lines so this should clear up any confusion



thats it for now im going to do a bit more on how to adjust the fuel
and also get a picture of the three different types of carbs that the twin hitachis setups used

heres the emission type carby's




and the flat top carbys


and the "original GX" type roundtops



and here is how i have been shown to tune these carbys
this pic shows the the fuel adjusting screw at the base of the su and the pusher which you push and if you push it up and the motor doesnt change revs then it is tuned


heres a pic showing what happens when it is pushed up

top quality post mate

I had to download su service manuals and really read around to get all that

These are also good sites for SU info.

Hitachi SU Tech Page

General Motor Tech articles w su info

again very informative, a great idea

Cheers, J

no worrys i might go pull apart one flat top emission type a flat top non emission type and a round top and take a picture of them in an exploded view

ok pulled apart the non emission flat tops and the only noteable difference is that the plungers are slightly taller on i think the flatys so they seem to be the only non interchangeable parts
and i havent got the balls to pull apart the emission type carbys as they give me shivers
and heres some pics of those horrid twin a14T su's of the emission variety
if you happen to get this type of setup then id advise to source non emission style flat tops or round tops as i am certain that even though they have the diagonal bolt pattern they will bolt up to this style of manifold
pics kindly supplied by ddgonzal (thank you)

Yes, those A14T twin carb Hitachis have a lot of emission controls on them. The pics there are missing the electric chokes and EGR valve, which has been removed and blocked off.

A14T carbys have 4-bolt flange on manifold side, and small 3-bolt flange on air cleaner side.

In edition to EGR and electric choke, they have servo (throttle control) similar to USA emission controlled downdraft Hitachi.

Tons of hoses and check valves and such.

A14T type

Thanks heaps , this info will be very helpful, as I have A14T type setup to go on my wagon.
Will definately be bookmarking this for later reference

Quote:

i was always under the impression that if you raise the pin, you want the revs to rise slightly then fall back to idle speed.

yes your right thanks for correcting me