Carb cleaning

[Action]

I just picked up a 1984 125m and seems to run really well but has kind of a hanging idle. It could be the cable but I want to go thru the carb and clean it really well. Any thing I need to look for? Can't be much to it? Also where should I start on the air/fuel screw? 1 1/2 out ?
Thanks jack

[yaegerb]

Does it idle down after you blip the throttle? If so the slide could be sticking and I would soak the carb throat and slide in chemtool.

[kb0nly]

I got a 125 here doing the same thing that i have been working on. Some days it behaves the whole ride, and then the next time it races or hangs after letting off the throttle. I tore down the carb twice now, checked cable movement its perfect, about to give up and buy a new chinese carb for it and be done with it so i can stop spending time on it.

The mixture screw says 1 3/8 in the manual, but 1 1/2 is about right on the one i have been tinkering with. It runs good and strong just that crazy variable idle problem. Oh if you need the manual for it look in my signature below....

[2010iron883]

My bike ran until my buddy started the car while it was hooked up to it. i have replaced the cdi , and now the spark is blueish white but isnt making it up the center of the plug. i have replaced the plug with a ngk, cleaned the coil, snipped the wire . I cant seem to figure it out. how do ya tell if the carb just need s to be replaced instead of rebuilt. I set my pilot screw by the manual, but it is kinda pitted from age of the needle part of it. 2/ and a 1/4 turn out is what i did, when i try starting it the plug is really really wet when i take it out, i know its gonna be damp but dang it almost drips/. i know it needs rings but the boy before was riding it. He did ride it without a battery for a long time too.

[kb0nly]

If the plug is that wet then its running too rich, i would check the valves as well. What do you mean it isnt making it up the center of the plug? If its arcing off to the sides then the plug has a cracked insulator and needs to be replaced, new or not it happens.

[Lamont]

Usually, a hanging/high idle is an air leak. Check the intake between carb and head. A tiny crack or bad o-ring can cause hours of tuning frustration.

[c_e_carter]

It may be the needle valve and seat leaking, especially if it is revving. I just replaced mine and now it acts like new. Just did this on my 86' 125.

[kb0nly]

If it was a leak it would be consistent problem wise though. The one i am working on you can ride it for hours or even days and then suddenly it revs instead of idles, i thought it might be a leak to but its not acting like an intake leak. I plan on putting a new carb on it and just going over everything again.

[Furno]

My guess is a lean condition of some sort. that usually comes from one of 2 places, Make sure there arent any particles in the bottom of your tank or the bowl on the carb. a slightly blocked pilot circuit and you CAN get a lean condition, maybe clean it up and add or replace a fuel filter? either that or an air leak on the intake will pretty much always lean it out. spray some ether around the carb and boot while its running, see if it idles down. thatll help you find any leaks.