Buy 4 cheap scales at Target or Walmart and put them under each wheel not only will you know the total weight but you will know the weight balance of the four corners of your kart with or without you on it. Makes it nice it add weight to the right area of the kart.
That’s fine but it still wouldn’t tell me the weight of the Tony for comparison. I’m hoping that one person will know the weight of the Road Rebel and another person will know the weight of the Krypton.