I have recently finished a Patrick Racing 110" upgrade with 10.25JE Pistons, 2mm oversized valves and spring kit, Dyan 3000 ignition, ported intake manifold and a 48mm Big Air carb, and Monster Pro headers.

I'm having a problem that I can't figure out if it is a fuel delivery problem, or some kind of electrical ignition problem.

After starting and riding the bike for 20-30min at speeds under 65mph, the engine starts popping and missing and starts losing speed. At times it completely dies as if you turn the ignition off and you come to a stop. After waiting a few minutes it will start back up and seems to be OK for about a 1/4 mile then it starts all over again. At first I thought maybe the Dyan ignition was going bad, so I put the stock box back in but it does the same thing. I have had the engine apart several times and the heads show that the carb is rich as there is coal black carbon build up after 100 miles

If anyone has any experiance with the Big Air carb, or knows for sure what my engine is doing please help...this beast is unridable the way it is now...

O1hotrod.. Don't know of anyone using the 48mm carb. but I would get that straighten out first and see if it doesn't fix the problem. I'm guessing that it will. do you know how the carb is set up as far as jets and needle?
never mind I just realized your talking about those genesis carbs.. I think someone on the rsr forum has experimented with them.. not sure..

I'm guessing you're talking about the Genesis carb? You could read through this thread - Genesis

The tech info from PSI says to make sure you have vented gas cap, or you will experiance flooding. I thought the way the motor was acting seems more like an extremely lean condition.
At $75 an hour I don't think I can afford to let a dealer play with it.
Also the fuel pump has been eliminated, and no throttle position sensor.

I thought I had heard of someone using that carb, quite a read..looks like Randy is tring it out, maybe he will pop in..

not having the tps won't make a dramatic difference..I ran without it for several months..I now have a voes. The way you describe it, It does sound like it's starving except for the carbon buildup.. When I went pumpless, I had to put a larger needle valve assembly in to allow a better gravity flow to the bowl...(hsr 45mm).