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Mystery misfire

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Nurse Julie:

--- Quote from: Mototech on June 25, 2021, 06:50:47 PM ---
--- Quote from: philward on June 25, 2021, 05:57:56 PM ---Stating the obvious - if its only a mis on 1 cylinder, its got to be that cyl HT circuit, that cylinders carb/inlet -
maybe sounds like float height/float valves (think thats what Julie might be getting at)
What model? HT lead in good order?standard airbox or pods? exhaust? Any recent rebuild/adjustments?

--- End quote ---

As 1 & 4 share a coil, I would have thought the misfire would have effected

It is 1977, all as it left the factory, I have stripped & rebuilt the carbs with new needles & needle jets & fitted electronic ignition, symptom is the same as before.

--- End quote ---
[/quote]
Just because you have stripped carbs and fitted some new bits, that doesn't guarantee its not a fuel problem.

K2-K6:
If you wind the air screw for idle mixture in and out one carb #1 while it's running you should get a response as the mixture  changes,  between 1/2 and 3 turns out should give a good range that you can clearly hear in cylinder running.

If it doesn't do this in changing response,  then there's the likelihood of that idle circuit being impaired.

Also run it in the dark and look carefully for leak sparks from that #1 lead to see if there's any compromise there. They can leak out to the rocker cover on the way to plug where it's nearest.

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