Hello everyone, this is my first post. Like a lot of people here, I had the joy of owning a mini bike when I was a kid, and I still ride at 63. I have looked here and no one else seems to have tried the combination that I have just built for my 4 youngest grandkids, age 5 to 12. I was given a 2013 Baja Viper, with a 2.8 horsepower Lifan engine. It had a bad carburetor and would barely run. Having rode a copy of this bike with a good running engine like I have, I decided not to waste a dime fixing it. Instead, I bought a HF 3 horsepower Predator and put it on. Choose the 3hp because it is for lightweight (45-80 pounds) inexperienced riders. Rear sprocket is a 70 tooth and the front was an 11 tooth clutch. To gear it down for more power, I bought a 10 tooth clutch. I want to thank Max Torque for their help as this is not a common item. The new clutch came with a light blue spring (1800 rpm engagement). Haven’t rode it yet but it sounds strong and will do 3720 rpm with me holding up the back of the bike. Has anyone else done this? How will the blue spring work out with the kids? Jay