https://www.topspeed.com/powerful-inline-four-motorcycles-that-are-not-sports-bikes/
The wildest motorcycle here is a 201-horsepower motorcycle that is a touring bike, a sports bike, and an adventure bike all in one!
inline foursports bikespowerfulmotorcycles
https://www.jalopnik.com/heres-what-happens-when-you-bolt-four-engines-together-1833107401/
First the Garage 54 ENG team bolted two inline-fours together to create a custom straight-eight in a display of wrenching wackiness. Then the mechanical madmen...
happensboltfourenginestogether