Hey guys my F4 was stolen, crashed and recovered recently and i was planning on putting her back together as a street fighter but the engines got a pretty loud tapping now and I don't want to have to rebuild it or anything. Just wondering if anyone had a similar sound and could give me some good places to start to check, otherwise I'm just gonna part her out. She starts up just as easily as ever but when she was crashed the two exhaust runners on the right side of the bike were completely crushed so perhaps this may have caused a backfire and burnt a valve or something I don't know. Could also b the cct but I've never heard what a failing one sounds like. Thanks for the help all:

 

To me it sounds like an exhaust leak, did you take off and put on your headers? Are they torqued correctly?