Motorcycle Repair: Loss of Power/fuel loss, air fuel ratio, motorcycle mechanic

Question
1972 CB500/4. Novice motorcycle mechanic. Got the bike from a friend completely out of whack. I think I got everything adjusted right. I was having a problem with gas being dumped from the overflows *a lot*, no matter how much I've adjusted the floats. I've taken apart the fuel valve (little needle valve aperature) and cleaned it completely. The vents seem to be clear, so I kept adjusting the floats down and down until it would stop spraying gas from the overflow (with some force, too, which I thought odd, as well the bowls seem a bit overfull when I take them apart) Now it stopped dumping gas (for a bit) but now seriously loses power at anything over 3000 rpm. Could be floats set too low, and it's running out of fuel at higher rpms? Why is gas *shooting* out of the overflow when I adjust the floats up?

Answer
Alex, you are correct it sounds like the float levels aren't adjusted properly yet.  There's a specific float level the have to be in order for the bike to run correctly.   I've often hooked the carbs to the fuel tanks, turn them right side up and made sure the fuel actually shuts off at the correct height.  A lot of times it's hard to judge just when there enough pressure on the seat to shut the fuel off.  The method I described is a sure fire way to make sure they are set correctly.   It's a whole lot quicker than trial and error.   Just don't blow yourself up or burn your garage down.  Gasoline is a pretty powerful explosive when it has the right air fuel ratio.  

Good Luck
Rich