Cylinder not firing

[Pain]

My number 4 cylinder just does not fire. I thought it was oil backing into the cylinder, but a change of plug (with good spark) still gives nothing.

I am opening up the carb, but really have no idea what I am looking at. It seems to be okay, but if I have spark, and no fire, i would need gas, right?

Other symptom, white smoke from that side exhaust, no smell of oil right now.

Thanks

Andy (I wanna do my own work, but am mechanically impaired)

[DiverRay]

White smoke tells me you have gas as well. WAY TOO MUCH GAS!!
If you have the carbs off, double check all float levels. I didn't see what year your bike is, but go ahead and look at the threads on the left.
Check the "Tech Tips" and look up carbs. You may just have some dirt or something stuck in the needle, or the carb may need a complete overhaul. The tips will tell you how, and we can answer anything that may come up.
Just remember to lay all the parts out on a CLEAN surface as they come off, and install in the reverse order.