Have some weird poping noise comming from top end of my blaster its a 2004 I just got it about 2 weeks ago it seems to be in wonderful shape I know it has been rebuilt guy told me it been bored and stroked don't remember what I can do to these engines its been years since I had my last one if anyone can point me in a direction lmk because at the moment I'm stumpt btw I'm new to the site and I apprecuate any help I get from everyone thanks fellas!