Carby Idle getting lower and lower

Vikingimike01

Well-Known Member
Local time
11:15 AM
Joined
Jul 1, 2018
Messages
1,492
Location
Hungary
Hello forum!
I have a 2 stroke 66cc china engine.
I have drilled two 1 centimeter holes in the stock black circle airbox. One over, and one under the NT logo.
The other thing is I have 2 exhausts, and the one that this 66cc had is the one where the baffle is ~15cm long that goes back into the exhaust. I had a different baffle part, that was about 5-7 centimeters long. I put that one on for better airflow too.

As the title says, my idle is getting lower and lower, the engine usually stops. I have screwed it in half a screw from where it was idling OK as a new engine now it barely idles. If I twist the throttle a bit it stays low for one or two seconds, then races up quite high.

What is the issue? Still running too rich? It has normal torque and top speed, not much 4 stroking

(About 1 and a half tanks on the engine)
 
Last edited:
hard to do any tuning until motor has 2 or 3 hundred miles on it
 
Might be an air leak don't know if you use the radiator hose for connection but if you used the idle screw and if your getting a slow reaction might be a leak or a bind throttle cable.
 
warm up the motor (about a mile) and set idle - see if that holds when warm and wait for motor to run in a bit more
 
if you can't turn it down with screw when hot, then it is most likely an air leak
 
It idles very low when cold.
It gets hot, bogging stops.
Idle goes up. I can turn it down tho.
 
Last edited by a moderator:
unless excessive, that sounds normal for new motor - after it runs in more, idle will be more uniform for both hot & cold

I don't like to stall out when motor is cold on new bike, so often run the idle a bit too high when hot just to keep it running till it warms up.
 
Yeah but it's getting worse and worse. I may be running rich or lean. I hear weird loud engine noise if I keep the throttle in one place. I speed up a bit and boom its gone.
 
Back
Top