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Denso X22ES-U is the correct type.
[...] Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.
Quote from: Nurse Julie on November 13, 2023, 02:45:14 PMDenso X22ES-U is the correct type.Going to go with these Julie as heard there are a lot of fake NGK's around. Do you have a reference for ND for CB750K0 and 400/4 please?
Quote from: davidcumbria on November 14, 2023, 07:08:14 AM[...] Run iridium in most of my bikes which definitely help starting but can’t see one for the 550.Any new sparkplugs will help starting. Some in the German forum have tested iridium plugs but were not impressed. These plugs will do well in modern bikes however which run much leaner than our filthy beasts.