If a motor on a bicycle offends you, go read another thread. Last year my wife and I built our tandem, starting with a custom Ti frameset. This year we got into BMX cruisers and a bit of racing. Next project? Choppers. They'll be pedal powered, but I'm sure at least one will end up with a petrol motor fitted into the frame. For the design we're using, we could even use an electric motor. Not quite the speed of my 400HP Camaro, but it will be a fun project. Some enthusiasts tinker with their bikes, and if they want to add a motor, I say go for it.