Yamaha Jupiter FI – Pros and cons

After 11 years of entering the Vietnamese market, Jupiter is considered Yamaha’s money-making machine. The all-new 5th generation Jupiter has just been launched and Yamaha claims it has many outstanding advantages, but there are still disadvantages.


Jupiter FI is one of Yamaha’s important innovations in 2012 because this model plays a decisive role in success in the digital vehicle segment. It must be admitted that Yamaha’s new car has many advantages such as youthful and sporty design, powerful engine but very fuel efficient, frame system that brings high stability…

Vehicle frame system

Contrary to previous models, which used rubber damper engine suspension, Jupiter FI has replaced rubber with a rigid mounting system, in order to optimize engine power to increase the power of the vehicle. car.

The chassis system provides high stability when operating

Furthermore, the rear fork has also had the horizontal tube removed, and the hardness of the upper and lower surfaces of the rear fork has also been adjusted, ensuring higher stiffness compared to the old “Jupiter” models. The combined effect of these improvements has resulted in high operational stability.

Fuel-efficient engine

The vehicle uses a 4-stroke SOHC engine, single cylinder with a capacity of 115 cc, electronic fuel injection, air-cooled. This is the first Yamaha digital vehicle line to apply electronic fuel injection technology along with changes in design to optimize the efficiency of the air intake and exhaust system to help increase engine power but save fuel.

FI electronic fuel injection technology helps the car save fuel

Along with the application of FI electronic fuel injection technology, a synthetic plastic fuel intake pipe and a new throttle assembly were also chosen. With a piston diameter and stroke of 50mm×57.9mm and a compression ratio of 9.3:1, the engine achieves a maximum power of 7.4kW /7,750 rpm.

Optimize the drive system

The primary and secondary transmission ratio is changed from (3.315→2.900) to (2.714→3.154) to optimize the drive force to the rear wheel. To create this driving force, the gear width of numbers 3 and 4 is widened to ensure reliability of the transmission system.

Gear ratio changes to optimize drive force to the rear wheels

New cylinder technology

The spindle-cast cylinder is a technology that was first applied to Yamaha motorbikes in the Southeast Asian market. The outer surface of the cylinder bore is constructed in a shape that not only increases the contact surface area between the cylinder bore and the cylinder body but also increases high precision due to the solidified aluminum alloy surrounding the areas. Protrusions on the outside of the cylinder bore during casting help enhance heat dissipation and improve engine stability. In the timing system, the roller rocker arm is used to replace the sliding rocker arm to reduce friction between the rocker arm and camshaft, ensuring smooth engine operation and minimizing losses. release power and save fuel.

Other features

The display system on the speedometer has a completely new design with the application of LED lighting system with effects. In addition, the speedometer is also equipped with a fuel level warning light and a dynamic error notification function for the operator.

The redesigned rear seat has a slim size, ensuring a comfortable sitting feeling while also bringing a compact image to the rear of the vehicle.


The plus points make Jupiter FI a car worth the money customers spend to own it. However, this is not a perfect car. The writer would like to point out a few small drawbacks, providing suggestions for the manufacturer to further perfect its vehicle.

Stiff front shock absorber

Yamaha equips the new Jupiter with shock absorbers, oil dampers, and springs. When observed, it can be seen that the damping stroke of the front shock absorber is quite short. This makes the driver feel the hardness quite clearly when operating the vehicle on bad roads.

The damping stroke of the front shock absorber is quite short

The hard front shock absorber acts directly on the steering wheel, causing fatigue for the driver when having to continuously hold the steering wheel when traveling a long distance.

Rear fender is too high

To ensure fashion for the overall appearance of the vehicle, Yamaha designed Jupiter’s rear fender to be quite high. The cross-section of the fender is small, angular and tapered downwards, making its task more formal than blocking dirt from the tires during operation.

The rear fender is raised high

This disadvantage also makes other drivers behind this vehicle feel uncomfortable when operating in the rain or dirty because water splashes high behind the tire.

The gear lever leans forward

The car’s gear lever is not arranged properly. It is placed forward, so when the driver wants to shift into gear, he has to put his foot deeper. Changing gears every time is quite inconvenient. On the contrary, the gearshift lever is too high, so when downshifting, the driver has to lift his heel to operate.

The gear lever is tilted forward in the front, high in the back

The rear handle is not improved

This is the 5th generation but Jupiter’s rear handle (since the first generation) has not been improved. The rear handle has a thin edge, which makes the handle not smooth when lifting, dragging the rear of the car, or turning around.

The rear handle has a thin edge that makes lifting the rear of the vehicle uncomfortable

Jupiter’s rear is still known for being much heavier than the front of the car, making it difficult to lift. It still has the old handle design, making it uncomfortable to lift and steer the car.


Weight of 104kg, quite light, helps the car easily turn, turn, steer, and support acceleration very well. However, this feature has led to 2 unreasonable points on Jupiter FI.

Light weight makes the car unsafe at high speeds

Firstly, when accelerating from 80km/h or more, the car begins to show some undesirable points, the vehicle’s stability begins to decrease and no longer feels as safe to drive as below 60km/h. The light weight is not enough to keep the car compact when traveling at high speed, so at this speed, the car begins to switch into “floating” mode and makes the driver feel hesitant on the throttle.

Second, light weight means front disc brakes are very dangerous if used improperly. Jupiter’s head is inherently very light, and the front fork’s travel is not long, so if you accidentally brake suddenly with your right hand, the driver will be in danger. Conclude The philosophy of developing the Jupiter car line is a combination of convenience, sporty design and high performance. Yamaha has done that well in this 5th generation. Despite some minor disadvantages, what the Japanese motorbike company equips on this car still makes customers satisfied.

See detailed photos of Yamaha Jupiter FI

The Dat (TTTD)

Photo: Le Thang

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