Anyone know what this could be? I've checked the floats and they are fine. The air filter is on properly. I'm lost.  :dunno:

Do a search for "backfire."

A gen-u-wyne backfire is fuel igniting in the exhaust, which is typically a spark, compression or timing issue.

I just took it for a test spin. It runs fine at WOT. After it warmed up, it started backfiring less. It still does it though. I'm having a problem with one of the plugs fouling at low RPM.

P.S. I just scared the wilderness outta myself with an oil patch leaving a stop sign. I almost went for a lo-side --  

So you either have a problem with excess fuel supply or not enough spark on that side.

I did the 't' fuel lines like in the race section. I completely took out the intermediate fuel chicken and there's no reserve now. I was told it might flow too much fuel like that. I thought the jets and stuff controlled that. Should I partially close the lines, or does it need to be rejetted? It's got the jet & pipe kit. V&H can, but I didn't have the bike when the work was done so I dont' know what the jetting is like in it.

That'd be the first thing to check... the jets might be way wrong.

Thanks a lot. I really appreciate the di-rec-sciones.

I'd suggest that first you try checking the bolts that hold your exhaust in place, and the gaskets.  The one time that I've had backfiring issues it was a leaky exhaust gasket, and that's really easy to check.

I had the backfiring problem back in the winter when I was getting everything sorted out. All it needed was new plugs.

Yeah, I just put new plugs in it. It fouled one and after I cleaned it, it ran great for a day. I'm still having a huge problem with one cylinder running super rich and the other real lean. The only thing I know to do now is take the carbs apart and see what's goin on in there.

Not saying this is the problem, but when was your last valve adjustment done?

I have no idea. I would guess some time ago. My father is bringing me the tools to do a valve adjustment this weekend.

Sounds like it's time for an overhaul.  Do valves and check the state and jetting of the carbs at the same time.  If it's got the stock exhaust, you might want to just pick up a set of stock jets and replace them anyway (check for appropriate replacement size in the FAQ if it isn't stock).  They're very cheap, and you don't want to have to take out the carbs and find that the jets are off, then have to put them back together, get new jets, then take them apart again...