Ariels famous square four was not the only motorcycle produced with this engine layout. Here are seven some lesser known models that have been produced.
"The engine employs a compact layout of the water-cooled square 4 in order to suppress the air resistance of the front part, and integrates the right front-rear cylinder and the left front-rear cylinder. Twin carburetor specifications with suction ports connected to each, and fuel injection was also developed accordingly. The 2 in 1 exhaust pipe designed with priority to the design has made two independent on the inside to prevent power down". In the racetrack, the KR 500 (having four rotary valves) was no match for the RG 500. I don't know how would have performed this one, as a street bike. I mean because of the very long intake ports, on the two front cylinders... Greetings from Brazil.
