my front cylinder has to have a plug change within 400km after i had a top end rebuild. cleaning of the plug with brake cleaner does not work, had changed 3 plugs already for only 1500km. i use BR9ECS front and back, not remembering having any problems with the back cylinder. where could be wrong and what should i look out for? solutions please. plugs look black but no trace of structure change. thank you for reading!
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