So my Boys have a side by side. It started blowing smoke the other day. They talked to some guys and did some internet mechanicing and it's looking like a head gasket. Two cylinder engine. Has anyone changed one and is there a trick to it? It's very accessible but I do see an overhead cam under the oil cap. That tells me there's timing involved. Are there dots to line up on two gears like cars? (used to be) I was a mechanic back when but today is a whole nother ball game. Thanks.