Different exhaust vapour??

Hi, Just fitted a Power commander III usb and using the supplied map for (stock exhaust + K&N airfliter)
i now seem to be getting 1 exhaust (left side of bike) showing much more vapour than the other even after engine is warm
and even if I rev it the vapour remains.
Can anyone suggest where I should be looking to cure this?

Thanks

 

Switch a sparkplug from another cyl into that hole or try a new one.

 

Thanks,
Spark plug appeared at fault. :-(
New full set fitted, everything back to normal .
Thanks for your advice squirrelman