Replaced Head - Now a couple issues
My son's 01 SPI was running fine but we decided to replace the head proactively. I bought him a new, aftermarket head. The install went fine, and it even seems to have a little more power now, but it also "rattles" or "taps" under acceleration now. If I rev it a little bit, while in neutral, it will also backfire; not a loud backfire, maybe even more of a gurgle. Any advice as to what we should look at??