Justin, I am fighting a cold, and am leaving for a trip early in the week. But, if you want I'll come look at it, say... Monday eve. Maybe even Sunday eve before sunset. If I have time I'll break away tomorrow. Get some items just for PM.... Plugs, carb cleaner, gas filter, and tank dryer. We may need other items.. and we may not need anything. But you will have them for future use in any case.
My bet, knowing the engine is this:
1. Fuel Filter Needs changed. It's that in-line one. You can get a replacement for near-nada at Bethany Imports on the south side of Downtown on S. Robinson. Or go to Kerr Import Parts on NW10th just off Broadway and near Java Dave's accross the tracks. They can fix you up. Put a rag on the tank side of the line and gently clamp it so that you don't tear the hose. Pull the hose clamps, pull the filter and replace. Clean up any small gas spills. This alone may cure your problem, assuming it's gas.. I think it may be. (oh, I always put on new clamps) Take your hoses to the carbs off and blow them out and put them back on. This next is shadetree... but I would take the fuel line and blow on it to make sure the line is not clogged.. listen for the bubbles in your gas tank. Yes, really... it is backyard, but it works in troubleshooting. (someone here will suggest something better, I am just telling you what I do.)
2. If it's gas and the fuel filter is changed and it's still missing.. do several things. In fact I would do these anyway, just a routine thing and this will be a good chance to get into some PM. Pull both of the ICT Pod Air Filters. Take them and clean them with soap and sprayed water, rinse good and if you have compressed air blow them out... shake them of the water let them dry and air out (use a blow dryer!).
3. While the filters are off, I would take a clean small rag (no lint) and wipe the inside of the carbs as much as possible without losing the crud (if any) into the carb. (ICTs).
4. Start it up.. if there is still a little missing, then shut it off, spray some cleaner inside and let her set. After the fumes have blown off, start it again and see if this clears it.
5. Also as a PM... we have had a lot of rain, or moisture in the past weeks. I would add some gas tank dryer to the gas tank and run it through. You'd be surprised how much water we get that way, or through the pump. (this is something I would do after you find your problem)
If it's not gas, I would push and pull on the plug wires... see if any are loose, cracked, or burnt. Check your wires at the cap and coil too. If that checks out, there may be a chance that you have a bad plug. I would buy a set of plugs (just pull them and get them at Bethany or Kerrs) Gap them and slap them in. Be careful, those are long reach... and the heads are soft 044s... be careful to thread them in right
Check your carb to manifold nuts, put a wrench on them an give them a slight tug.. you'll feel it if one has vibrated loose. Check the manifold to head next.
Unless you have gone over 3,000 miles your Valve settings should still be good... If it's still missing I would look at the compufire. I had that go out once and it did EXACTLEY what you described intermittently until it crapped. I found it by putting in a set of points.
If all the above fails and you have a miss... we will need to look at the carbs again, maybe clean the jets and also readjust the valves and see what's up.
I am willing to bet that if you do the above (except the Compufire, valves, blowing out the carbs) you will find it running like a champ.
If you are awake, send a mail and I'll call you. Jim (It's a 99% chance that it's a half hour fix and you'll be on the road) If I come over, I'll also show you how to set the ICTs..
