The logo of Yamaha motorcycles is the letters YAMAHA and a tuning fork graphic composed of three Ys. The logo of Kawasaki motorcycles is the letters Kawasaki and the graphic of a big K. Neither of them is an octopus logo. However, Yamaha’s tuning fork graphics are a bit like the octopus you mentioned. As shown below, they are the logos of Yamaha and Kawasaki respectively. The last gray one is the exclusive logo of Kawasaki H2.