Would have to be flywheel key MM.
I agree they are a nice motor - due to massive time constraints I have been working under since august, I have only been using a masport SP with that same motor on it- except the IC cast iron sleeve. Havent even touched a 2 stroke or anything since then. Fires first or 2nd go, good on fuel and plenty of power so no complaints
Pull start is weak as though - looks like they made it a large puller presumably to make it easier to pull over - downside is there is more flex in the starter and more force on the parts if you give it a really decent pull
