I Don't have one big enough that's why I was asking lol because it's inside the hub.its difficult to measure I think the back nut might be 28mm but not to sure wasn't want to buy the wrong ones 🤔
Couldn't see anything even when engine is out ,but as you I might need to take of a cover plate first. I wasn't want to buy a new recoil starter in case it's the wrong on .never had one on it when I bought it