New member here and was just given a 75 400 enduro.  I’m a Jeep guy but not very familiar with bikes. The Bike hasn’t ran in years.  I cleaned the tank and fuel shutoff, new spark plug, tore apart carb and cleaned but no new parts. I can get the bike to fire up but only when choked.  As soon I turn the choke off it dies.  Also, I’m 4-5 turns out on the mixture screw just to get it to idle.  Can’t give it any throttle or it dies.  Any input is appreciated. 

I found a carb kit for 77-78 but nothing for 75.  Anybody have a part number for rebuild kit?

Sounds like low speed circuit or pilot jet is obstructed. I dunked my carb in Berryman chem dip and others reported good results with ultrasonic cleaner to ensure the gunk in those small areas is removed.

Greetings from Tennessee  

Hey there Lawson, you are half way there. Other people on here will give much better advice than I can, but you might try
going through the carb checking all the jets and orifices as the choke system obviously works
there are many other things (like a clogged pipe...) but usual checks would be
air filter and air filter box leaks
all rubber fitting from carb to bike for leaks
throttle slide correctly seating all the way down and adjusted at throttle
having everything at standard settings may help, so check the needle is seated and clip position
those are some things that I would be doing,

Welcome from NZ. Something's not as it should be if you have the mixture screw 5 turns out.
Must be nearly falling off the thread.
It's in for rich & out for lean so set it at 1.5 from fully in.
That might help it get through the initial leanness off idle.
It's important to remove the jets & the center long needle jet plus the idle mixture small jet up in the body to be sure its clean. Maybe you're used to carbs with fuel screw out for rich but these are air screw so in for rich--ie--less air.
Could raise the slide needle by 'lowering the clip' to get it through the mid-range.
Possibly a crank seal but they're pretty robust on those so stick with the carb at this stage i think.

Pahiker, thanks for remedy. I've got a carb now that needs cleaning.

Lawson, make sure you have fuel coming in, float is somewhat level to carb base in general, and all is clean. make sure the holes on the inlet of the air filter side of carb are clean. no airflow there = no suction through low speed jet.

Bribe a friend that has real motorcycle carb skills using booze as needed.