Topic: CB100ish has trouble idling once warm

[Tugboat]

Ok so this is my CL100 motor on a CB125 frame with CL100 exhaust. Bike runs great - up to 65mph (indicated) on flat ground. Fires right up too. My problem is that once it warms up it doesn't want to idle. I have to keep blipping the throttle at stop lights to keep it from dying. I've cleaned these carbs more than once - jets and passages are clear. Idle screw is set to stock spec and mix screw is turned out until it has no effect. What are some possible causes od my idling issue?

[RAFster122s]

Could you have a air leak that's opening up with heat/expansion?  Some carb cleaner or ether is one way to show where they are if you can keep the twist of the wrist limited while checking.  It has some risk as you are adding a fuel source.  It will take a couple people to test and have a CO2 extinguisher handy to rob the combustion of oxygen and not have a dry chemical mess to clean up or destroy the motor.
David

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[grcamna2]

tug,do you have a pic of a spark plug that's been running in it? what color ?

[Tugboat]

I'm hesitant to pull the plug again, since the last time I put it back in the threads seemed a little iffy. But the plug looked great. I'd had the main at 117.5 but went up to 120 to see if that helped any - and the 120 was too much. So I'm back to the 117.5. Slow jet is stock. Stock main is 105 but I've had to upjet due to the CB125 intake, which I had to modify as well.

I will check this weekend with some starter fluid & see if there's an air leak somewhere.