The vertical line shows the rotation of the rear wheel, the resistance, the rotation load, the engine speed (rpm) and the horizontal line of motor speed (km / h) corresponds also to the position of the transmission gear. From the diagram below, we can see the relationship between engine speed and motor speed for each transmission gear position, between engine rotation with rear wheel rotation.
Rear wheel drive power is the power required to climb the maximum incline / maximum power and speed at each gear position.
** Correlation Between Machine and Motor Speed In Each Dental Position **
This correlation can be qualified by knowing the reduction of the ratio of each tooth and the rear wheel diameter (effective diameter of tire / effective diameter).
If the motor engine rotates around 400 rpm, the motor speed will be around 10 km / h on the 1st gear, on the 2nd gear about 17 km / h, on the 3rd gear about 25 km / h and in the 4th gear about 30 km / h. If engine speed is added 1000 rpm again to 5000 rpm, engine power and torque are also increased, allowing the motor to climb / climb and generate the required power.
The engine's maximum speed is the speed at which each gear position is positioned. On the YB 50 motor maximum engine speed 7000 rpm. Motor speed will decrease slowly after passing round 7000 rpm indicating maximum rotation. However, when the engine speed is increased to 8000 to 9000 rpm, the motor speed also shows an increase, but the rear wheel drive diminishes gradually and actually the speed does not increase in that state. Therefore, on testing the engine acceleration performance, engine speed is increased to a maximum value of 7000 rpm in gear 4.
Raise the engine speed until the rear wheel drive diminishes gradually called "over revolution" and can shorten the life of the engine. On the tachometer there is a warning area for this overreving.
** Specific Fuel Consumption **
Specific fuel consumption and fuel consumption indicating how many kilometers a motor can take with 1 liter of gasoline. In the specific fuel consumption indicated is how many grams of fuel used by HP (horse power) / hour in general the highest engine efficiency (lowest specific fuel consumption) occurs where the power curve and torque curve are equally highest.