I have a 1991 Fatboy and the carburetor is running rich in the front cylinder and I cant get any adjustment out of the adjustment screw all the way in and all the way out makes no difference, And my fuel mileage is way down, but the bike runs good So I started working to remove the carburetor but I ran out of time today got to go to work. My question is that the carburetor can be rocked up and down are they supposed to do this or is there another problem going on.?

 

"loose"

 

The breather tubes that go to the jugs hold it in, the rear of the carb is in a rubber sleeve. It's a tight fit, it rocks. That's how you get it out, by rocking it.
But it shouldn't move if the breather tubes are tight.

 

The backing plate supports the outboard side of the carburetor. The breather tubes are just soft rubber.

Once you have removed the backing plate the carb will pull out of the manifold.

When removing the screws between the backing plate and the carb (after you remove the bolts that secure the plate to the cylinder heads), make sure you remove them one turn at a time, while pulling out on the backing plate, so that you don`t damage the retaining threads in the backing plate.

These threads are a retaining feature that will prevent a loose bolt from backing all the way out and being ingested into the engine.

 

Thanks for the help, I have never pulled a carburator before, so I have got to be sure to do it right.

 

Thanks for the info. I will do as you said and take my time so as to do it right. the reason I am rebuilding it is because I am running real rich in the front jug. My friend that is good with carburators tried to adjust it but it wont adjust. He could do this carb. work for me but I get tired of asking him for help and the only way to learn is to do it yourself. Thanks for your help.

 

While you have the carburetor off, remove the intake manifold and replace the seals, you probably have an intake leak on the rear cylinder.

Otherwise both cylinders would have the same fuel air mixture.

Don`t change any jets.

If your friend was good with carburetors he would know that when you have a single carb, both cylinders will get the same air/fuel mixture.

The carb cannot make only one cylinder run rich...

Remove carb and clean. Be careful when you remove the idle jet mixture adjustment screw, there is a spring, a tiny washer and an o ring in there.

When you reinstall the mixture adjuster screw, turn it gently until it bottoms out, did I mention turn it in gently?

Then back it out 2-1/2 turns.

Replace intake manifold seals.

Once you have a clean carburetor and new intake seals you can determine how the jetting is, I bet it will be fine.

 

I want to think you for all of your help. I just got the carburator off today, I guess that I will need to get the intake off so I can put new gaskets on it, That looks like it's going to be fun. I will rebiuld the carb first. This bike is a 1991 fatboy with Vance and Hines pips and Screaming Eagle air cleaner. My question is the jets that came in this bike new are Main Jet- 160 Slow Jet - 42 this is for Ca.
All of the other states the Main Jet-185 Slow Jet-45
The jets that are in it now are Main Jet-180 Slow Jet 52 does this sound right for a Two stage upgrade.?

 

That main jet is in the ballpark (180-190 depending upon your build)....BUT that slow jet is way too friggin big (45-48 is the norm)

She will be running too rich most of the time.