Well, I got a chance to check out the sled last night. Thanks for responding.
I pulled both carbs and checked out the air srew really good and it's clean as a can be. The jets are 320, is this a correct jet? Removed needle and Jets, clean, you can see right through. Used compressed air through passages.
Checked the boots, there in great condition.
Assembled, same problem. I had air screws in all the way and it runs 4K RPM.
Sprayed carb cleaner all around the motor for any vacuum leaks, found none.
Both piston valves are all the way down but the throttle is tight, so I will loosen that but, I'm not convinced that that's my problem.
Larger Idler screws turned out, it's not holding the valves.
What else is there?
I removed the spark plugs and one was new the other not. It was wet and looked, well almost oil fouled. Piston tops have carbon on top and clean around edges.
Not sure where to go from here? Any suggetions?