I've been tinkering with this bike for years (cosmetically). PO put pods, 4 to1, and dyna ignition (that i know of). I'd like to sell it but i want it to run right before i put it up. Couple years ago i fired it up to take it for a ride and it was running rough, chalked it up as dirty carbs and it has been sitting since. Made my decision to pass it along so i took it to a "carb guy" over the weekend. Long story short, it runs better but backfires and pops around 5k rpm. I checked timing, carb sync, spark, all good. Haven't done a compression test yet, didn't have the right adapter. But i noticed #4 exhaust is not as hot as the rest. Pulled plug, double check spark, good. Put plug back in, fire the bike up, don't hook up the plug wire and the bike runs even better with no backfiring. So it's running better on three cylinders instead of four? What is going on here?