Happy Valley
Active Member
Motorcycles are custom made, such as by chopper builders making proprietary frames, and DOT licensed so they can apply legal VINs and supply MCo/MSOs to title and legally register a vehicle.
The real weakness in modern, mass production, bicycle frames from is simply they are built to be lightweight with drawn tubing that was never specced to have engines clamped to it vs straight wall pipe that motorcycle manufacturers use. The larger the engine the more under-specced it is and why motor-assisted-bicycles are most appropriately utilized with small, low power, lightweight, helper engines. Just try to get a bicycle manufacturer to honor a bicycle warranty or cover liability after learning you clamped an engine on their product.
The real weakness in modern, mass production, bicycle frames from is simply they are built to be lightweight with drawn tubing that was never specced to have engines clamped to it vs straight wall pipe that motorcycle manufacturers use. The larger the engine the more under-specced it is and why motor-assisted-bicycles are most appropriately utilized with small, low power, lightweight, helper engines. Just try to get a bicycle manufacturer to honor a bicycle warranty or cover liability after learning you clamped an engine on their product.