Triumph Thunderbird 6T Fouling Plugs


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Q: I’m trying to find out if I have the correct carburetor and jets on my 650cc 1966 Triumph Thunderbird 6T. I’m having trouble with fouling plugs after a rebuild. Who can I contact, or can you help me? I have tried contacting Amal


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A: I looked through the manuals I have from Kim the CD Man and came up with two options. It looks like 1966 was the last year for the 6T. You should have the Amal Monobloc kitted out like this: 376 carburetor, 230 main jet, .106 needle jet, needle type C, clip in position #3, slide 376/4, pilot jet 25. Should you for some reason have an Amal Concentric, the setup is as follows: 930/23 carburetor, 230 main jet, .107 needle jet, standard needle, clip in position #2, slide #3. Hope this helps.

11/9/2017 4:31:07 AM

No mention of plugs, wires or coils or type of ignition, But a good EI such as Pazon, Boyer or Trispark should cure many ills, critical to fit a good coil, the originals were none to great when new and after so many years are suspect. Best to test them, but I like to use a modern Harley coil hidden away. 3.8 to 4.2 ohms for Boyers is optimum, never more or less than that. Check specs for other brands. many people start out a rebuild on the wrong plugs. The plugs i recommend are NGK B7ES,, some will fit a B8 and those might be okay for a well seasoned rider but they will foul very easily on most bikes. Also check you are getting full output of your charging system,, weak power will cripple any ignition. If in doubt fit a new SPARX high output alternator, rotor and solid state reg/rectifier. Always remember though that all electrical problems are fuel related and all fuel problems are actually electrical. Gotta start somewhere,,

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