View Full Version : One rich plug, one lean plug....

08-03-2011, 05:39 PM
Left is rear cylinder, right is front. Can think of a few things that would cause this off the top of my head. Bike has 13K on the odometer and has been thoroughly maintained. Plugs have about 1.5K on them, not much. Swapped in a set of IX's (platinum) and noticed this when I pulled the old ones out.

So...could be (?)
TB's out of balance
vacuum leak
injector issue
bad plug wire

I dialectic grease everything to start with, bike runs fine when warm, off idle stumble when cold. Checked for vacuum leaks in any of the small hoses and nothing. Did end up replacing the airbox to valve cover vent line as it had developed a split. Changed the oil and replaced the gas tank lid gasket. Have to admit, haven't been doing a whole lot of spirited riding on her lately at all so I felt the need to bond with a bit of TLC.

Was thinking of sending my ECU off to AF1 to make sure the latest Map2 was installed. Battery is good, injector connections are good. Anything I'm overlooking? Bike runs fine, just want her to be perfect.