based on the throttle valve opening and incorporates a correction using an air temperature sensor and an engine speed sensor. Initially, the injector was installed directly above the intake pipe and attached directly to the delivery pipe, but it was changed to a method in which it was attached to the side of the intake pipe and the V bank pipe was connected from the delivery pipe with a rubber hose. The ignition also adopted electronic control in accordance with the fuel injection. A pulse generator is installed at the rear end of the intake-side camshaft to notify the igniter of the ignition timing. One igniter is installed in each bank and six coils are installed in the bank to distribute power. In the mass production specifications of 1986, the fuel injection was changed to Bosch's mechanical type. It was adopted because Bosch's mechanical fuel injection is easier to adjust. In mechanical fuel injection, Bosch has one more control element than Lucas (later TRW → ZF ), and the injection amount can be controlled more accurately. Volumetric efficiency varies depending on the engine speed, but Bosch can be controlled according to it, but Lucas cannot. Since the fuel injection pump was installed in the V bank, the six coils that had been installed so far could not fit. Therefore, he reduced the number of coils to one bank and changed to a method of distributing power with a distributor. The fuel injection pump is driven by a belt by the intake side camshaft of the left bank, and the shaft is extended to the rear of the V bank. Five-valve It uses five valves with three intake valves and two exhaust valves per cylinder. Yamaha has already used a five-valve on a large motorcycle so that technology was diverted to the OX66. Honda adopted a φ90X52.3mm and ultra-short stroke (big bore) to increase the valve area with four valves, so the combustion chamber became flat and combustion was not stable in the extremely low load range. Since the OX66 can secure a sufficient valve area by adopting five valves, it has a short-stroke configuration to secure output in the high rpm range with φ85.07X58.5 mm, but avoids flattening of the combustion chamber. The engine has a high output and a very wide power band by stabilizing combustion on both the high and low revs. The intake valve has a larger