Cleaned carbs 3 times, right is coming out the exhaust normal, left 1/2 strength. Put a credit card over 3/4 of the back of the carb, it finally picks up and fires right. Valve clearance? Rings seized from sitting? The bike has 7k and sat up some years, looks untouched only the carbs, breather messed with. I restored a bike like this in 92, switched frames(not this bike) Drinks gas to run, chunky . Any ideas?