I'll send a pic off to Gary Jamieson, and he'll be able to tell me what that pulley was for. There was some wonderful story that came with the tractor, about it being the third one that Gary ever sold, with the first two going to him and his daughter. He told me that that was probably not true, as he'd already been selling them for 6 or 7 seven years before he bought his. He told me that he had sold over a thousand of the 135s, and I love the idea of all those old yannies way up the dirt roads, hammering along, doing their **** jobs all these years on. I would suspect that most of them are still running. I cannot get over the cave-man simplicity of the design, and just how well and how long it has held up. When the dozer at work starts throwing codes and complaining about charging system voltage, the 40 year old yanmar is thumping along, starting a campfire in its intake manifold to get going on cold mornings. I love it to pieces.