Join Date: Jan 2009
Location: Boise, Idaho, USA
After rebuilding my carbs, on the '76, I chased similar problems. Carbs r & r 5 times after rebuild. I was instructed to switch plug wires and found the problem. The plug wire on #1 cyc had burnt and was arcing. Mine was easier to diagnose the miss due to having HD twin mufflers installed w/o crossover. Follow Randakk's tech tip and get everything else top condition before rebuilding the carbs.
I also removed, cleaned, and had tank lined. I used salt water and a DC current for rust removal. I removed petcock and sender unit and taped up the holes with duct tape. I believe the positive applied to the tank itself. Negative applied to a sacrificial rod inserted into salt water. The instructions I had, said to use 10 amp charge. My battery charger would only put out 2 amp for about 2 and 1/2 minutes before the thermal coupler would break and about 3 minutes later it would reset and cycle again. Two hours later I dumped the saltwater and took the tank to a radiator shop for lining. The operator stated that he had never lined a tank the looked that good.
While the tank was in the shop, only about 20 hours, I "opened" the fuel sending unit and cleaned it. I spent about 20 minutes doing the cleaning and made the non-op sender work like a new unit. Use caution and don't break anything. I scraped the build-up from the hard metal portions and used break cleaner on the windings.
Be sure to flush the fuel system and replace the fuel filter before restarting the engine. Remove the the fuel line from the pump to the carb and crank it over for a few revolutions. If chasing the other possible problems solves your miss, your carbs will not be plugged by rust in the fuel system. Sorry for the long post, and yes I can talk all day! Good luck. Keep us informed.