So I got my 1986 Kawasaki Vulcan 750. Brand new carb rebuild, new spark plugs, new battery. Front cylinder is firing just fine. Both spark plugs working. Two rear spark plugs have no spark. Swapped the coils and rear coil produced spark in the front. Once swapped back i had spark in the rear for about 20 minutes. After I run my bike for 10-15 minutes the rear engine is dead cold. I checked all my fuses and electrical connections. Thought maybe my computer was bad. Anyone have any idea?