[jeffahart]

I really think you are having ignition trouble. Have you looked around the clutch pivot bolt and z bar? they are right on the side of the block. An easy place to drape a wire and have it get yanked when the clutch is pushed in. Also, when you install the air filter and cap, it can relocate wires a bit without you noticing as it's pretty much right on top of the distributor. Bottom line, trace and check all ignition connections and re-crimp and ground; it will only take you a few minutes and you can check it off the list.

It's always easy to blame the carb first thing. Else, swap the carb with a known working part.

Good luck,
j