Yes I think some clarification is needed as to the problem.

If it bogs with choke closed, does it run with it half open, or still bog? Mine is set normally in the middle position, I just leave it that way. Occasionally it seems to run rough and I need to reposition the choke.

Can you not drive this thing at wide open throttle at all no matter where the choke is?

Also, I'd ask what kind of gas you're using and how old it is? The book says these things want 90+ octane. I have 87 in mine and if it sits in there for two long it runs like crap.

I think it is imporant to note you have replaced your original carb with a mikuni unit as it seems that was lost a little throughout the thread.

It does not bod with the choke closed. If the choke is on it misfires and does not go to it's full potential speed. I usually set it at middle position but the problem is that it misfires or backfires. I don't know the difference between them but it either misfires or backfires. A person with a little more knowledge could explain me the difference. Yes, this is a minkuni carb. Also another problem is that the choke cable is a little to small.

I just opened the spark plug out and it was all black. Does that mean the atv is running rich.

Yes. Black plug would be rich.

Allen

If it were rich would you turn the screw in or out.

I believe in to lean it. Are you sure the choke is operating correctly?

Also what size jet is in the carb? Maybe it is too large.

Allen

The choke is operating correctly. I do not know the size of the jet but it is the stock one that came with the minkuni carb. Also what jet are you talking about, I thought there were 2 or 3 different types of jets.

Clarify for me what size engine(cc) and what size carb(mm).

If you are installing a performance carb on a stock engine it may be jetted for performance filters and pipes etc. The easiest solution is to change the main jet to a smaller size.

Allen

This is for a 110cc atv. The size of the carb is a 19mm. Why does it matter about the engine size.

It said on the website this is for a 50cc to a 110cc.

Okay. That carb is appropriately sized. It may actually be a bit small for a 110.

A 50cc engine is going to require less fuel than a 110cc engine. So the same carb may work, but you would need say a size 86 main jet for the 50 and a 98 for the 110. Those are just examples, I don't know what size you really need. Someone else may know. (Forchetto)

Another thing may be the float setting. It may not be set right.

Allen

Is your carb like this one?

http://dratv.stores.yahoo.net/19waca.html

It looks like for your ATV you should have about a #75 main jet and a #38 idle/slow jet.

I have a parts 19mm carb that I think it from a 70cc engine. Will open it up and take a look to see what it has.

Allen

I'll open my carb up to see what size it is. Before I even get into anything I will try to play around with the mixture screws.

Try the mixture screw at about 1.5 turns out and adjust from there. Not sure if you will be able to adjust it enough though.

Allen

Take the choke cable off and let the choke open all the way, You said it was too short right.

Yea, I already removed the cable.