Every review I've read on these carburetors or on the tune up kit itself says that there carburetors ran very rich out of the box. Most had to go to steps down in jets. I meant to buy one step down but I actually went to steps down on the primaries and left the secondaries alone for now. I was getting a 12.1 to 12.3 at wide open throttle but the air doors we're not opening all the way so I figured with a little more air that would have brought that up a bit where I like it..