Moped Army

I just put a new mbk av89 cylinder, and an av10 head on my 50v. I case matched and matched the intake 15mm. I have spark and fuel and seem to have no obvious airleaks but it wont start. Was running before doing all this with a different carb. now running a 15dell clone. I used the regular 50v head gasket because I did't have a rubber ring style gasket for the av10 head, could this be an issue. I know I will be able to get it to run just want to make sure this rubber O ring wasn't a major issue and go chasing other problems.