Yamaha probably doesn't know exact weight until Viper comes off assembly line in Fall goal was up to 50lbs lighter than Nytro AC 4s weight probably will be a bit lighter as Yamaha likes to beef chassis up. I'm thinking 505 to 525 lbs dont 't think Viper will be below 500lbs but just a guess on my part. Yamaha knows they have to reduce weight of new products but not to the point where quality is at risk. Typical Yamaha sled buyers want power & reliability over the lightest sled on the planet. Visit TY to understand Yamaha owners hot buttons lots of high speed straight liners & huge mile trail riders few boondockers but some.