Uploaded March 2026 | Updated September 2026, 1 week ago
We get a ton of questions about this full custom BBR Motorsports Supermini 125 build from the previous video, so here is a rundown. This is a complete one off Supermini sized bike that we put a YZ125 engine into. I have tons of fun ripping Supermini sized bikes but struggle to keep them alive as an adult. We talked about just building an aluminum framed Supermini (the YZ85 comes with a steel frame) to keep the frame from bending and breaking everything around it. But had also talked about putting a 125 into a Supermini so that it has tons of fast, fun, and reliable power. My dad (Duane Brown) got to work on this dream project putting in over 300 man hours of milling, welding, machining, and grinding to make this thing a reality. This is NOT a cut down 125 frame, he made the frame from scratch. Nothing off of a YZ125 or YZ85 frame was used. By the end of it he made a full one off aluminum Supermini frame, linkage and swingarm, rocking a YZ125 engine. We made sure to make the YZ125 air intake boot fit so that it didn’t lose any power, along with the YZ125 dual radiators so that it stays cool. We are running KTM 85 forks/clamps since they are the biggest diameter around out of all the 85’s. It still runs the stock YZ85 subframe, seat and plastics, with a custom aluminum gas tank (the stock YZ85 tank only has enough room for 1 radiator). The bike has a Pro Circuit YZ125 pipe/silencer, All Balls Racing bearings and seals all around, Dubya USA 16” 19” wheels with Dunlop MX34’s, along with Maxima oil. Huge thanks to MotoSport.com for helping to get all the parts needed. We made this bike purely to have tons of fun on, and this bad boy is always an absolute blast to ride!
We get a ton of questions about this full custom BBR Motorsports Supermini 125 build from the previous video, so here is a rundown. This is a complete one off Supermini sized bike that we put a YZ125 engine into. I have tons of fun ripping Supermini sized bikes but struggle to keep them alive as an adult. We talked about just building an aluminum framed Supermini (the YZ85 comes with a steel frame) to keep the frame from bending and breaking everything around it. But had also talked about putting a 125 into a Supermini so that it has tons of fast, fun, and reliable power. My dad (Duane Brown) got to work on this dream project putting in over 300 man hours of milling, welding, machining, and grinding to make this thing a reality. This is NOT a cut down 125 frame, he made the frame from scratch. Nothing off of a YZ125 or YZ85 frame was used. By the end of it he made a full one off aluminum Supermini frame, linkage and swingarm, rocking a YZ125 engine. We made sure to make the YZ125 air intake boot fit so that it didn’t lose any power, along with the YZ125 dual radiators so that it stays cool. We are running KTM 85 forks/clamps since they are the biggest diameter around out of all the 85’s. It still runs the stock YZ85 subframe, seat and plastics, with a custom aluminum gas tank (the stock YZ85 tank only has enough room for 1 radiator). The bike has a Pro Circuit YZ125 pipe/silencer, All Balls Racing bearings and seals all around, Dubya USA 16” 19” wheels with Dunlop MX34’s, along with Maxima oil. Huge thanks to MotoSport.com for helping to get all the parts needed. We made this bike purely to have tons of fun on, and this bad boy is always an absolute blast to ride!
