Idle Help 1980 ATC 185

[zsoccerdude17]

Im having what I think is a bit of a problem with my idle. It seems to just randomly cut out. Its not a nice smooth beat 100% of the time, which I believe it should be. New plugs, new coil, new mikuni carb, supertrapp exhaust. I have a video for it idling. And you will see in the video once it randomly sorta idles up. But hitting the throttle hard it seems to go just fine. Just an idle issue atm. I then took it out and did a couple full throttle passes down the street, and am including the plug chop from it ( brand new plug)
Also when engaging first gear it seems i really have to hit the throttle to get it to catch/move at a decent pace. Trans issue ? or the nature of the beast. Also at high rpms i get some popping while under load?
Any help much appreciated.

video here http://youtu.be/-aa8mOzXTs0

159577

[250sxman]

Is your carb jetted correctly to compensate for the aftermarket exhaust?

[zsoccerdude17]

I have done nothing to the carb. I was thinking that but im not sure on the model of the carb, or where to find it in order to get a jetting kit for it. Does just opening up the exhaust a bit warrant a re-jet?

[250sxman]

In theory, yes, but I am no carb guru, I'll let others chime in on that, but that may be the reason behind the popping at higher rpms.

[zsoccerdude17]

Hopefully someone does as ive tried almost everything i can think of .

[250sxman]

There's a good stickied thread about carb jetting theory here, I think in the world class help section, give it a good read , it may help.

[kb0nly]

By the plug it looks like she might be running a tad lean... Hard to tell with the small picture on my phone that i am viewing it from right now but i see just a hint of tan on the upper edge of the insulator and it looks like it might be a bit lean by the color.

If you put a free flowing exhaust on it you probably need to bump up the jet size or at least adjust the mixture screw a bit to compensate.

[zsoccerdude17]

I also have the ilter box completely removed and just a K&N filter on the end of the carb. I think ill buy a jetting kit and see how it does. Only problem is idk what model of mikuni this carb is. Is there a spot to look?

[zsoccerdude17]

Also ive never rejetted a carb, only rebuilt. Am i just jetting the main? or the needle? How does it all work?