It would be nice to know where the jamming of the linkage was happening, because it may come back since you probably haven't changed what was causing it.
To get a stable idle - mainly, to keep the engine from stopping when it is idling - you must have either a "normal" idle stop screw in the bell crank on the carburetor's butterly valve, or a secondary governor spring to give you a governed idle. Your carburetor does not have an idle stop screw, or anywhere to put one, so you must fit an idle spring as shown in the picture I posted earlier. Otherwise there is simply no mechanism there to keep the engine from stopping if you put the speed control on the handlebar in the idle position. The throttle butterfly will meander about at excessively low speed until you happen to get a flameout.
