1982 ATC 110, do I have a different carburetor than stock?

[tundrawolf]

Well, I have done a lot of things to my ATC 110. I have adjusted the vales (They were way loose), cleaned and lubricated the air filter, leaned the carburetor out a little because of puffs of black smoke via the slide needle and some jets from one of my Trail 110's.

The "plug" that is where the idle speed adjustment turns out to be a broken adjustment screw. I drilled and ez outed and tapped the hole, and put in a screw from one of the trail bikes.

However, even WITH the screw, it STILL does what it has done before, which is barely idle even when warm, and will die within a few seconds of releasing the throttle. The carburetors on the trail 110s have larger (Lower) float bowls, and a fuel strainer underneath the fuel petcock. The carburetor on my ATC 110 is much thinner, almost half, and there is no strainer.

I have been all through this carburetor and everything is OK.

Do I have the wrong carburetor?

See attached pictures:

http://img.photobucket.com/albums/v237/wolfmangk/ATC/0329101512.jpg

http://img.photobucket.com/albums/v237/wolfmangk/ATC/0329101511.jpg

[atc350xer]

It looks exactly like my '82 110 carb

[SWIGIN]

For one thing you have it on sideways....lol

Other then that it looks about right but It has been awhile since I looked at a stock carb.

[Mr_RPM]

my 84 atc110 looks different, but mine is a different year...

[mopar_man]

My '82 has the exact same carb.

[tundrawolf]

Any ideas on why it will not idle?

[3wheelmecca]

clogged low speed jet, poor jet stack adjustment, dirty. Almost looks like a CT90 Carb, but those were made over a wide year range.

[Walkerallen]

those are the same problems that i'm having with my 110

[rdlsz24]

Did you try cleaning the carb? That is step one

Rob

[tundrawolf]

Oh yes, I made sure every port and passage is clean and clear. This problem is boggling my mind.

[squirrel1182]

Mabey you could try pullin one of your carbs off of your trail 110's and seeing if itll idle better and if it does just buy one of those and put on it.

[tundrawolf]

Mabey you could try pullin one of your carbs off of your trail 110's and seeing if itll idle better and if it does just buy one of those and put on it.

I have thought about that. I am not sure if it would fit, and Walkerallen is having the same problem with his.

OK, so when it is cold and I start it WITHOUT the choke it wants to gradually idle up to a very high RPM (runaway idle). If I apply the choke, then the idle will actually return to normal, until the engine warms up. When the engine warms up, it will not idle, even with the idle screw all the way turned in. There is a point where if the idle screw is turned all the way in, where the idle will sort of runaway like it does when the engine is cold, choke off.

Any ideas?

Oh, I have also adjusted the slide needle downward with no effect. Also, the float level has changed, but it still acts the same.

[Mr_RPM]

did you check for airleaks?

[tundrawolf]

did you check for airleaks?

Not with a torch, no. I am almost positive there are none, but when the wind winds down a little bit I will check.

[mopar_man]

Is your throttle cable kinked or pinched somewhere? Are your handlebars turned when you start it? That could cause the idle to go up. When you took the carb apart, did you replace everything that can be replaced with a kit or just clean everything so that it looks good?

[tundrawolf]

I don;t think the cable is kinked but I will check it out. I lubricated the cable, it was the first thing I did. I cleaned it out, put a new float needle in it, and replaced the main jet.

[mopar_man]

Are all the holes in the main jet holder clean and clear? Is the slow jet clear? Are the holes in the slow jet clear? This is what replacing all that is easier than messing around with it, hoping it's all clean. The main jet holder doesn't come in a carb kit unfortunately. Is the idle mixture screw in good shape and is the spring still behind it?

[tundrawolf]

All the holes are clean and clear. The mixture screw is in good condition and the spring is intact. I made sure everything was clean. I disassembled the carb completely with the exception of the choke assembly. I started it up today and same thing. I had to choke it to bring the idle down. Then, because it was still cold, the idle was very high. I checked-and zero air leaks.

[mopar_man]

Well, just because it looks clean doesn't mean it is. Carb kits are under $20 and include everything. Is there a burr on your slide that's maybe hanging up on the guide pin? Does anything happen when you adjust the idle speed screw?

[tundrawolf]

I cleaned them out with wire, it is very clean. I will check the cable and for burrs.

[tundrawolf]

I am just stumped on this one. The cable is very smooth all around, no burrs on the slide or in the slide bore. Today I went to try to start the ATC, and it wouldn't start. I quickly realized it was the spark-the spark was jumping to the insulator. So I replaced the spark plug, thinking I had found the problem. No, I hadn't. Still acts like always.

Have to turn the idle screw wayyyyyyyyyyyyyyyyyyyyy in to get it to barely idle, and whenever I gas it, puffs of black smoke come out of the exhaust. It runs great though, except for the idle. Argh! Unfortunately I don't have the money for a rebuild kit, I MIGHT if the machine didn't run, period, but it runs. It leaks a little around the carb bow because I had to make a gasket for it. If I was 100% sure a rebuild kit would fix it, I'd probably do it. It just doesn't make sense!!

[tundrawolf]

I noticed something. In the throat of the carburetor as it goes into the intake, there are two small holes. One is directly above the idle jet, the other is in front of it, slightly offset. When I plug the hole nearest the slide, and plug the mixture screw with my finger and blow into the purt where the idle jet goes, I get no air out of the outermost hole. Does anyone have a schematic of the carburetor (Keihin PB??) ?

I think I have it figured out. There is a passage that goes underneath the hole closest the slide, that goes from the idle jet to the mixture screw. There is a brass ball blocking it. I need to remove the brass ball to clear the passage. Any ideas???

[tundrawolf]

OK both brass beads blocking the ports are 2.5MM each, one on the exit of the carb, the other on the side of the carb, but relating to the idle jet. Also, I do not believe it was necessary to remove either one. Both passages are rather large, and didn't seem to be clogged. But I had to know. Maybe my problems are due to float level? I wish I had the $ to get the rebuild kit. Everything else seems to be fine.

[MTS]

Is your float hanging up on your homemade gasket...?

[tundrawolf]

Is your float hanging up on your homemade gasket...?


Great question- No it is not.

[tundrawolf]

Friends, I thank you for your help in this matter. After all of my work, I figured it out. I put in a ginormous slow or pilot jet and leaned out the needle two positions. The pilot jet says "35", but the "37" I compared it to was at least 2/3 smaller, unless Keihin is going by a "Larger number equals smaller hole". I put it in, and the bog is gone. It has never run better. I got done with a great ride today. Thanks again!