Skis & Sleds — Weekend Adventures With Mr. Tippy by Lou Dawson March 2, 2009 by Lou Dawson March 2, 2009 I’ve been riding and modifying “Mr. Tippy” lately. That’s the nickname I tend to use for our Yamaha Nytro snowmobile; a high-tech low-pollution 4-stroke machine that works well for ski access, but nonetheless is a bit on the heavy side…