carb issues?

[cadee]

Hi I have a 1981 Invader 440 and am having what i think is carb issues.
I have cleaned both carbs thoroughly and reinstalled them, all fuel lines are new and so is the fuel pump, all gas is new as well and so are the plugs, but... i dont know how to get the idle/mixture? set right. How do i do this?
It will start and run, not sure what the idle RPM is supposed to be.
When i give it gas, with the back end raised on a stand, it seems to bog a bit but will rev up, it seems to have a hesitiation though.
Thanks in advance for your help!
Cadee.

[mswyka]

Before answering the questions about carbs, have you checked everything else out with the engine?

I find the carbs are very reliable if they are clean.  There are a couple of air/fuel passages that are easy to overlook in cleaning and require some special attention.  The air passage for the pilot jet is critical.  Also at the top of the main jet/needle jet there is a small reservoir or moat around the hole the needle slides through.  This moat holds fuel that is aspirated at idle.  If the moat is dirty or if the passage way into this moat is blocked the sled won't idle properly.  Idle speed should be right around 3000 RPM.  Carb cleaner, compressed air, and a torch tip cleaner are good resources to use.

[cadee]

Ok when i say i "cleaned" the carbs i took the bowl off and sprayed carb cleaner through every hole, every area etc i could find. I put on all new fuel hoses and put on a new fuel pump.
One thing i just realized is, i never took out the idle screw, is this something i should have done and sprayed the heck out of it with carb cleaner? Is this what you are calling the "air passage for the pilot jet"?
Also, you mention the "main jet/needle jet", is that the little area where i took off a little clip and pulled out some sort of valve? this would be in the "bowl area" and it had an "H" shaped thin metal piece attached to it. I did that and cleaned it too.
Sorry for all of the questions, this is my first time cleaning a carb.
Thanks everyone!
Cadee

[Checkmarks]

Sounds close to cleaned carbs cadee, then only close.

Pulling the bowl there is one "critical" passage.  The idle jet is the item to look for.  You need a slender flat head screwdriver to remove the brass idle jet.  It is the passage the fuel "flows" through at idle and that is critical.  This passage is tiny and exits in the mouth of the carburetor.  Replace that brass idle jet and ensure that idle passage is clear (not obstructed).  Now you have a clean carb idle system!  Short cuts just cleaning the idle jet may work but then it may cause you more work when you get to do it again and again.

Always good to replace the main jet (brass and hex sided).  Cleaning the jet may not get it clean since the orifice is critical.  The main jet has its passage through two devices, the needle jet and the jet needle.  One looks like a needle and one looks like a tube that the needle fills.

The air passage for the idle system is the screw that does NOT lift the throttle valve (round slide thing).  Pull screw, blast cleaner and its clean (exits in the mouth and the rear opening).  Clean the choke circuit and after that, you can call the carburetor clean aside the obvious cleaning duty of the carburetor housing/bowl.

mswyka=Mark is first hand experienced dealing with intricacies of these carbs.     

[mswyka]

Mark, the other Mark that is, gave you some good guidance.  Here are photos of the needle jet.  Notice that in the center there is a "moat" around the hole that the needle passes through.  There is a passage from the carb body into this moat, the passage and the moat have to be clean.  I use a small torch tip cleaner, but any small diameter stiff wire that fits inside the groove will work.  They tend to build up "gook" that may or may not come out with air and carb cleaner.

[Habbeli]

Do you want a tip, put down nozzles in fluid used in soldering brass, they look like new after that 
Add also the idle jet 

[cadee]

Ok thanks everyone for the proper cleaning tips, I will use all of them and should then have an excellent running sled!

[jimvw57]

The 'jet' with the H metal piece on it is the inlet valve and if it is not in perfect shape, could cause you to drain the gas tank into the motor. Best to replace with a Mikuni part (in my opinion and past experience) 

[mswyka]

I finally found the photo that I wanted to find.  This view shows the passage and if you look closely there is a build-up of black, oily, dirty stuff.