Over on YouTube we talk over the whole build about putting a CR125 engine into a CRF150RB. The frame and swingarm was cut up to get modern geometry. I saw a few people asking how much bigger this makes the bike. It ends up about the same size as the old KTM 105SX. The 150RB in stock form starts out a bit smaller compared to a lot of the supermini’s. To go along with putting the CR125 engine in and the frame mods, it has a fully hand made custom air box to keep maximum air volume for the 125 air boot and filter. A hand made aluminum gas tank that will make a 30 minute moto. A custom pipe to make sure it didn’t loose any power. Massive thanks to BBR Motorsports and Duane Brown for making this happen from the ground up. I wasn’t able to be there for most of it so this is mostly video that he texted along the way while doing it! We appreciate Red Bull USA for supporting the build along with Honda Powersports, MotoSport.com and All Balls Racing. Dubya did the wheels, Dunlop tires,Bud Racing...