[toomanytoys2]

You may still need a larger idle jet, but did you check yours for blockage? These things can clog if you burp, sneeze or fart. The A12 should still idle (maybe not the best) with the 35, and your symptoms do sound like idle circuit clogging. Next time you have the carb off check to see if all of the Carb's transfer ports are clean, you may have gotten junk in one of them. Spray carb cleaner through the idle circuit and make sure that it comes out of the ports (wear safety glasses). I am unfamiliar with your head a case model numbers, but a check for coil bind and valve to piston clearance will tell you if you are fine.

With the head on, rotate the engine until the cam is at max lift for the intake. Then using a feeler gauge, see how much clearance you have in between each spring coil. Then repeat for the exhaust spring.

For valve to piston clearance, pull the head and spread some room temperature play dough on top of the piston. Put the head and cam back in, then rotate the engine through its complete cycle. Pull the head and examine / measure the indentations made by the valves in the play dough. This will give you valve to piston clearence