Honda ATV help

[Lippy]

2000 Honda Foreman 450S. It didn't run at all unless it was on 1/2 choke so I took the carburetor apart and cleaned all the jets and moving parts. It ran fine with the exception of a few backfires during my test run after putting it all back together. It sat for a month or so and now I am having the same issue. I have taken the carburetor apart again and nothing seems to be clogged this time. It starts on choke and runs fine on 1/2 choke but as soon as your turn the choke off it immediately dies. I guess its a lack of fuel? Tested the float switch and it works so whats the deal? I even turn the gas off and let it die before leaving it sit. The only thing I noticed now that I didn't see before is this black plastic piece. I blew through the hose that was on it and can't get air through. I would assume it is this piece that is causing the problem? Any suggestions?

[BowSlayer]

On my Honda 250 I had the same symptoms and couldn't figure it out. Did some google searches and turns out the pilot jet is somewhat hidden and needed a special tool to remove it. I made a tool and removed it myself and cleaned it and it ran great after that. Don't know if yours is the same or not but I bet it is.

[Grndchecker]

I just rebuilt the carb on my 95 Honda 300. I bought an aftermarket kit at the Honda dealership that had all new jets, O-rings, gaskets, etc. Helped mine quite a bit. It did take three times to get all the settings right.
That hose is a vent from what I understand. Dirt dobbers could have plugged it. I would replace it .

[gatorgrizz27]

Pilot jet is plugged it sounds like to me. Also make sure the pilot mixture screw is set around 2-3 turns our, a lot of times guys put them back in and seat all the way. Start at 2 turns out and blip the throttle, back it out 1/4 turn at a time until the backfiring stops when you let off the throttle.

[tater_salad]

I kept doing the same thing on my honda 450. I did it like two or three times and kept having problems so I bought a rebuild kit. Worked perfect after that

[Lippy]

Got it going! I sprayed carb cleaner in that black thing until it started flowing out the other side. Gatorgrizz nailed the other issue. The pilot SCREW was all the way in. I turned it back 2 turns and it ran poorly. I just kept turning it slowly until it sounded good with no back fires. Thanks TBHers!

[Leonhogboy]

Well done TBH service center.