This is the Ninja JX21 B01 5 Port Port Off-Road Competition Buggy Engine from Mugen Seiki! This is a high performance 3.5cc Off-Road engine, using today's most advanced technology. The engine has been designed for maximum strength and highest specifications for serious and real racing. Fabricated from the finest materials available, it will insure less friction movement for higher speed and more economical fuel consumption.

The engine, OEM manufactured by OS Engines for Ninja, is loosely based on their V-Spec with some custom features: the crankcase is from the OS 28XZ engine, the sleeve port design is a bit different from the V-Spec, head design, the crankshaft appears to have the same 'DLC' coating as the OS Speed V-spec.