When the guys from Shifted Interests found a cheap Smart Fortwo with a broken diesel engine they knew exactly what to do. After removing the factory powertrain, they made custom motor mounts to hold a 998 cc inline-four from a 2002 Yamaha FZS1000 Fazer motorcycle to the rear subframe. The engine’s 149 horsepower and 78 lb-ft of torque is sent through a custom jackshaft to a welded Smart Fortwo differential supported by two heavy-duty bearings. The team machined the differential to use a motorcycle sprocket so it can be driven by a chain. They covered the new powertrain with a custom firewall made from 1×1 inch tubing covered in sheet metal. You can watch all this and a lot more custom work in the full build series. The team enjoyed the project so much they plan on building another with a Suzuki GSX-R750 engine.