Bike runs great when it is cold and for about 20 minutes after first start. When it gets really warmed up it will not idle properly. It runs fine but when you come to a stop the bike dies but will start right back up fine if you give gas. After this starts it will idle slow and die and something the idle will rev up real high. I adjusted the valve spacing, rebuilt the entire carb from new parts after it soaked in cleaner, and changed the spark plug. The bike is running very rich and the float is set properly. There was a Vaccum leak in the Air Intake which I fixed. Setting the pilot screw and idle screw does nothing to fix this. I am starting to think it might be the ignition coil. Also my muffler is shot, Back pressure issue?

Unstable Idle when hot with rich running. I can not seem to get this solved.

Also does anyone have any experience with the cheap Chinese Ignition Coils sold on Amazon and Ebay?

 

Sounds like you have found your problem, any bike likes to run rich cold, but won't run right hot with the choke on. Check the choke is working properly, that the air filter is not blocked and if they are OK, drop the main jet needle a notch.

 

Choke is brand new so it is not sticking and the air filter is new too. I check it again last night when it started stalling. I pulled the plug off and reconnected it to the ignition wire. The spark was very weak and orange colored. This is a new plug. Could this be the ignition Coil causing rich running because the spark is not hot enough to burn all the fuel?

 

Yes, faulty ignition parts can cause this. If you are going down the ignition route, change the plug first, check the regulator is not overcharging, then check the wiring, Few tests work on a machine that is running so substitution can be the only option. Change the coil then CDI then stator and or trigger unit.

 

I hope it is not the CDI unit. Those are very expensive. One for my ATV is about $400. I have a new coil ordered so I will see if that helps.