I have often wondered if there is a formula for flywheel size verses engine size. What I am getting at is a small engine with a large flywheel does run smoother and slower, I eventually would like to build one with a over sized flywheel, way out of proportion. I have thought of possibly gearing down the flywheel too. Some where around a 1" bore and a 2" stroke. Possibly using a auto brake disc for the flywheel since they are easy to come by and a matching bearing and mount can come from a junker. john