I have a cbr 1000f 87 model and at idel it has a nock, it has a new cam chain i have checked all the valve clearances and valve springs it runs fine but the noise seems to come from the front of the motor just under the head or around that area it sounds like somthing is hitting the side of the engin but when i rev the bike over 1200 rpm it gose away. have you ever herd of this and if so could you please tell me what it might be