ok so im starting to rebuild my cruiser engine. this is the first time I have ever rebuilt an engine, so I'm unsure where some gaskets go and if I should balance the pistions or not. I didnt mark them when I pulled them out of the engine and I just put them back in, so should I pull them back out and balance them? here are some pics of the engine and a rubber thing that I dont know where it goes I didnt pull any of the engine when I took it apart.