I was here a while ago talking about how I ruined my engine & needed a top end rebuild - the ebay vendor f*ed up & I'm just going to buy another 'nother one. The thought came though about how to know what model engine I have? I'm seeing stuff on eBay marked Set H CK19, 66-80cc and 47mm. If I could use this as an opportunity to increase from 70 - 80cc that would be great - just how to know what will be compatible. That is what I would like to know basically :> Cheers Guys.