Anything about motorising bikes, with refit kits or as-new. Electric and petrol are the two most common fuels.
This is a grey topic, and that a tag exists does not mean it is on-topic for Bicycles.SE
Some people want to fit a motor on their otherwise functional bicycle.
Some fit a noisy smelly polluting petrol motor with a tiny cylinder and displacement about the same as a shot glass, and the inability to start rolling without pedal assistance.
Others fit a more modern electric motor to an existing bicycle and find a way to strap some batteries in as well.
- If you want help with a liquid motor, then you might be best asking on https://mechanics.stackexchange.com/
- If you have problems with an electric motor, wiring, switches, throttles, display, battery life, or battery charging, then perhaps https://electronics.stackexchange.com/
