I bought a 82 Interstate in Dec. that run and sounded pretty good for being stored for a while. So I went to restoreing it before riding it. Rebuilt rear shocks, front forks, front & rear brake calipers and pads, had seat redone, timing belts, checked valve adj., removed and cleaned carbs., new tires, and alot of TLC. Looks and sounds great. Yesterday the weather was right, out I go to find out it way down on power. When you roll on the throttle it seems to spark knock I think. I rechecked timing GOOD. compression test GOOD. synced carbs GOOD. The only thing I'm not sure is vaccum advance? I unplugged it from the carb, not much vaccum and running didn't change. Can someone help me with how much vaccum it should have or how to check it?