Just saw an older gentleman break in his LA that way and it worked fine. The C/L people run their ABC engines that way all the time. Still Jett, K&B, and others build their ABC engines very tight and they could throw a rod if broken in on a rich four cycle. I suggest we read the manufactures instructions and break them in accordingly, if it says to four cycle their ABC engine, so be it. If the rod breaks it's under warrenty.