Huh? Didn't I just respond to this exact same enquiry in your debut posting last Friday? In my reply, I already gave you the name of makers and suppliers of the only 'motor ready' bmx cub frames I'm aware of here in the UK. My advice was to search online for something similar in the US where you are. No offense, but did you read my reply, or just look at the pictures?
In your latest post above (tip: makes more sense to keep your posts on this subject in one thread) you seem to be saying you're looking "...for ANY frame that can hold a motor". Even the quickest look at this forum will reveal thousands of bicycle builds capable of being motorized. In your particular case, it would make much more sense to simply purchase a 'regular' bike instead of spending way more having a BMX frame professionally adapted to accept a lay flat motor as pictured in my original reply. Even if you can source an off-the-shelf 'motor ready' BMX cub frame from someone in the US it's not going to be cheap. Such specialized, niche market things seldom are.
I'm confused when you ask "...has anyone tried rear axle chain drive?'. All gas-powered motorized bikes have rear axle chain drive, so I'm presuming you're talking about mounting a motor up-and-out-back to a BMX frame? If that's the case, maybe someone else can chime in with their input. Already said my piece on that kind of set up in my original reply. Only my opinion.
At the end of the day, if you want a motorized bike and would prefer to simply use an off-the-shelf 2 or 4 stroke motor from the suppliers advertising on this forum, it makes way more sense to opt for one of hundreds of bikes with frames that make this a straightforward proposition. Severely limiting your options from the git go by restricting your choice of frame to the bike you already own - one which because of its frame dimensions makes motorizing extremely difficult - isn't the best way forward.
