My 1994 YZF750R has developed a misfire at exactly 4000rpm. It won't\nrev beyond 4000 in fact. Absolutely fine up to 4000. So I can zoom\naround at all of about 55mph. This misfire was intermittent for a\nwhile and would 'clear' (power suddenly comes in and revs to redline\nno problem) after a few seconds. Now it doesn't clear.\nI'm thinking electrical connection - can anyone suggest what might\ncause these symptoms? What does the engine/electronics try to do at\n4000rpm? EXUP valve?\nHope the expensive looking black box isn't fried...\n\nCheers!