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SR400 FI Info from the Yamaha Japan site

'Automatic' translations leave a lot to be desired, but here goes anyway:

The biggest change in the new SR, Fyueruinjekushon (FI) and the exhaust catalyst is employed. Some harsh environments that require performance, air-cooled single-cylinder four-stroke engine that has a simple and universal mechanism to continue running in SR, SR had to evolve. But even after he debuted 30 years of more than a decade, has been continuously supported by many fans are thick stem SR should not be changed. "SR to remain." That theme was developed at the time.With its thick trunk, SR and Rashii styling, SR is ride guess.

To adopt the FI, the car is no carburetor specifications, you must attach a variety of parts. Or how the parts fit it. Been very difficult.Taru what is the fuel pump.

Falling natural gas from the fuel tank, mixing with air by negative pressure in the engine cylinders as the difference between putting it in the carburetor and fuel-air mixture, FI will determine the intention of driving conditions and riders, the program requires the mixture of The injection produces. For this injection, I need a pump.

FI fuel pump, the fuel tank has been placed in many of them, SR teardrop tank is not in that space. The center tank, they are doubling the oil tank through the main frame is narrower than expected from the bottom of the tank.

I set up a gas tank away from the fuel pump there. In addition to its built-in fuel pump has to be a new sub-compact tank.

Best place that I do not think I was just inside the side cover, there is a battery and regulator, Eakurinabokkusu has become a major problem or part of them and do coexist.

SR no battery cell is small, and more difficult to compact, a regulator, FI forced bigger due to the increased use of electricity. Cleaner air is more difficult to change shape dramatically.
So the battery has been moved under the seat. Sheets are based on a new sheet accordingly. However, the rear plastic cover sheet and the outline was the same as before.

Regulator was placed under the larger engine. The engine under Furemudaunchubu divided into two because this is housed in the meantime. Because the heat regulator that conducts electricity, must rely on air cooling. You win the regulator was also significantly higher cooling efficiency so noticeable if it was only under the engine.

Eakurinabokkusu have changed the new building. Or reduce the amount of space to ensure it affect the engine performance, moving to or from another location is not. Mm and the right to verify the shape and size units. As a result, we changed the shape of the Eakurinaeremento.

However, in its old space is still inside the side cover, could not fit the new parts, so each side was forced to 10mm overhanging side cover as new.Tsu feel uncomfortable with the rider that is of course, SR Rashii to disturb the silhouette has been thoroughly examined its shape.

Wear a catalytic exhaust Niatari has a new exhaust pipe and silencer.
Since the catalyst is placed in front of the silencer, the silencer is just that much longer, it is thick to ensure the capacity and the exhaust pipe. Thanks to the design Tepado Hitogado exquisitely designed and dedicated to finish and feel the change. To fit the silencer that has also changed the maneuverability of the exhaust pipe. SR's unique, three times bending curve is just beautiful, mm units changed the angle of the curve. Its finish is also instructive to compare so I do not know the difference between the old exhaust pipe.

The surface of the exhaust pipe of the new treatments even nano-film coating, rust and discoloration, and improve the adhesion of dirt.


FI is also essential to establish the O2 sensor has been struggling. Many of the O2 sensor, such as near the step is to place a discreet, SR does not have space to place them. So O2 sensor on the exhaust pipe was installed. But SR stainless steel exhaust pipe is chrome plated inner tube and outer tube 2 and have a double structure, here's a new boss for the O2 sensor is mounted on the manufacturing process, and very difficult is. Clear that the process somehow, also, O2 has the ingenuity and synchronize the line of the down tube of the frame stand out enough to prevent the existence of the sensor.

Even after these steps clear, there was a lot of challenges to be overcome. Among them was the most difficult was Mafurasute.


SR engine is not built-in balancer for canceling the vibration. Rijiddomaunto are in addition to the engine frame. Vibration that has a strong destructive power. But does not cause any problem in any part of the force on such a range of senior technical people, because those who were appreciating the wisdom and technology. This time, however, I had that exquisite balance and strength of the muffler change. So scarf with design changes, we ensure the strength and shape Mafurasute improvements. FI has adopted a new rubber anti-vibration mounts through the pump and tank for the sub.


FI increased by the addition of sensors, cabling is also increasing. Its volume, the volume is now over two times more car carburetor specifications. I also struggled to fit in a space vehicle that thin wire.

Despite the progress in digitization far, kind of meter you have Ryder always remain analog. Abolish the reserve by the FI of cock, but added that Metapanerudezain renovated the low fuel warning lights, is still a mechanical gauge and rev counter and speed. Right now, 250cc motorcycle that using mechanical meters or more rarely, SR is now seen as a rare presence.


FI has been attached, the same as before starting the engine, we only kick starter. The reason is, as has been the development of minor changes to stories told in the past, put the engine in the motorcycle kick pedal is why SR.

The first was concerned. Thus, in parts of the suit tried in the kick-FI became vehicles. Then I simply took the engine. Hito安心development is a team of all, I did that from there.

Era of kick starting the carburetor has been on the point. That's why charity is always improving, as the engine kick starter formula, SR may start was very good motorcycle. It's a completely different system with FI at the same time, because I had to ensure at least equal start so far.
If you just put the engine in terms of one, is not too hard. Where areas of high and low temperatures, however, and when you are warmed when the engine is cold, and nobody with the power people, and people who are not familiar with and accustomed to kick a goal under a variety of is clear in the very difficult.

Kick starter, but stepping on a pedal crank and unload three or four kicks to rotate, the chance to ignite the engine is only one or two times. Timed to spray mixture needed there, I shall also timed ignition. Throughout the button to rotate the crank at a constant speed, and continue to fire is very different cell type.

No ambiguity because all digital input and control would become too clear for engine start conditions. Asked to kick a lot of people stepping on where to collect data from a variety of crank, I set the engine start condition. As a result, I was able to achieve the equivalent of starting car carburetor specifications.

Looking through the instruction manual for the previous model "during the cold feeling completely shut off from full throttle choke knob" or "at ambient temperatures above 10 , full pull choke knob, one step back", it "When the engine is warmed, to start the engine throttle is opened slightly," and the tips were stated before the kick pedal, the new SR that does not require tips. Without having to manipulate the throttle and choke knobs, and allows the engine starting.


This research is the development of a facelift is unusual enough, the SR staff has discussed the development of a test drive in a lot. "SR What kind motorcycle was" dissected again, I discussed the pros and cons. Became the new FI SR is based on the discussion there, which they think make the SR. So decided. FI can also can create any feeling of why I decide to SR. Never, SR carburetor specifications, and do not reproduce in a translation.

So that was a big, SR has a "sense of Tokotoko" is. Common "sense Dokodoko" will be expressed, 400cc single-cylinder engine is up there is no sense of rhythm. Tottottottotsu and opened the throttle, feeling the light will be kicked to the ground while accelerating the SR 400cc, and because it feels very impressive.

But early in the wear FI is too smooth in the whole region. I have one of the characters are also single-cylinder engine, which it did not SR. So air induction system (AI) while promoting a clean exhaust, and made album feel thoroughly at low speed range in order to highlight the Shingururashi. As a result, their aim is "feeling Tokotoko" I was able to represent the firm. At the same time, the smoothness
Kashimashita the high rpm range produced in the early stages of development. This was extended to the FI by diameter 34mm throttle body, and also had a significant impact can be captured more air. However, two different characters I could meld the two engines, FI and largely Iemasu said.

FI until I put in here by creating a feeling that Rashii SR, in any way without making any internal engine was. As it turns out, the engine designers had secretly prepared a new cam. If you support stringent exhaust gas regulations, even if the FI also been installed, I thought it would affect the driving feel. But it was not adopted. If the cam is a good balance so far. The decision was right.

With the change in engine characteristics that can reduce the operation of the clutch, we were able to lighten the feeling of the entire body.

SR clutch, the XT500 has inherited its predecessor left. XT500 off-road model has also been large displacement was designed with spare capacity and the clutch. Clutch, however, the SR is now considering the use of a overengineer. The proper value to it, become more manageable clutch. Think so, added a hand around the clutch. Specifically, lowering the load of a spring clutch, clutch lever about 30 percent load reduction.