Discussion Starter · #1 ·
I have a ca. 1986 TB340A-C202 and each cylinder's plug is gold colored (good mixture/ temp). The problem is both cylinders won't run the same time because the CDI/ ignition coil is firing both plugs the same time at ONCE per revolution. If both plugs are hooked up, the default is the forward one will fire and the rear one won't. Top RPM is the same, 4,700 RPM, if the rear plug is hooked up or not. If I run the rear cylinder, max RPM is 3,900. Why is the ignition coil only firing ONCE per revolution? I took video of the plugs external to the engine, slowed the video to count sparks per revolution. The plug that's not firing, of course, is covered with fuel/oil. So I'm only burning half the fuel and have about one third power, as only one plug is firing, the crank is having to take the other piston for a ride. If I remove the either spark plug physically, max RPM is 2,500.