ORIGINAL: Dennis Flora
Short link to blade grip. Make longer to bring the blade up, shorter to bring a blade down. Bringing the low blade up will lower the head speed and make the heli more docile. I just answered your private message too... I think it went, let me know. What makes the blade come up is that it grabs more air and up she goes. Only make 1/2 turn adjustments at a time, thats usually all it takes to bring them in line with each other.
The reason it lowers head speed is you are putting in negative pitch. You should try to raise whichever blade is low to keep head speed up. You can put in too much negative very quickly and the heli won't lift off or you'll risk burning out motors due to requiring full throttle all the time. Which gives you no where to go if you need to avoid a crash.
An easy way to determine which blade is low is using a marker, draw too thin lines on th tip of one blade and a thicker single line on the other. Then spin up the blades and you can easily tell which blade is lagging. Make sure you set the tracking at a higher speed because that's where you'll be when flying. I clamp mine to the table across the skids so it can't lift off.