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I'm with Schwany, if you are just judging lean running from plug colour, it probably isn't too lean at all.Plug reading is not good with unleaded fuels and you should expect a light grey, not that old chocolate brown we used to consider correct.If it pulls cleanly up to your chosen rpm limit and doesn't make annoying noises on the overun, leave well alone.I doubt you are on the main jet long enough for it to affect the plug colouration anyway. The way to confirm if the main jet is too lean is to hold it at full throttle in a high gear and when settled, slowly reduce the throttle setting towards 3/4 throttle, if it accelerates, it is too lean, go up one jet size and try again. If that is OK, it's all down to the needle and needle jet.
I'm with Schwany, if you are just judging lean running from plug colour, it probably isn't too lean at all.
Plug reading is not good with unleaded fuels and you should expect a light grey, not that old chocolate brown we used to consider correct.
If it pulls cleanly up to your chosen rpm limit and doesn't make annoying noises on the overun, leave well alone.
I doubt you are on the main jet long enough for it to affect the plug colouration anyway. The way to confirm if the main jet is too lean is to hold it at full throttle in a high gear and when settled, slowly reduce the throttle setting towards 3/4 throttle, if it accelerates, it is too lean, go up one jet size and try again. If that is OK, it's all down to the needle and needle jet.
