Does anyone have a theory on being able to advance the exhaust cam 1 tooth, and not having to worry about whether or not the engine is at TDC when doing so? The instructions call for the engine to be at TDC. If all you're doing is advance the cam sprocket 1 tooth, does it matter? It really doesn't matter if its exactly at TDC. The relationship of the crank and the two cams is what matters. The cam lobes can point in or out. Just make sure the lobes are not compressing the buckets, this would make reassemble very difficult.