Plug wires running too close to each other may cause "cross-fire". That is when the wire next to the one firing fires through induction at the same time. If you are running a high output ignition keep the wires an inch apart - at least.
Retarded ignition timing can also cause the exhaust to pop.
Make sure all the plugs are gapped the same; I found that my engines like a small gap (.030") Some have better luck with large gaps (.040" to .060")
Retarded ignition timing can also cause the exhaust to pop.
Make sure all the plugs are gapped the same; I found that my engines like a small gap (.030") Some have better luck with large gaps (.040" to .060")
