My One B!tch About EFI

So I bought a leftover 08 a month ago and managed to get a few rides on it before the season really came to a halt. Great bike and I am very happy with it overall. I have one complaint on the EFI, though.

Why is it that a bike with full electronic control and EFI needs to have a fast idle button and a hot start lever? Every other EFI vehicle I have driven / ridden needs no manual controls because the ECU adjusts to suit the conditions on hand. I think it is ridiculous that I still have manual controls to operate when the ECU should be dealing with that. The extra controls are just more complexity and things to stop working along with the hot start lever being susceptible to crash damage. My GSXR1K works fine with no extra buttons or levers, so why does my MX bike need them?

There, now I feel better...:thumbsup:

Mark

So I bought a leftover 08 a month ago and managed to get a few rides on it before the season really came to a halt. Great bike and I am very happy with it overall. I have one complaint on the EFI, though.

Why is it that a bike with full electronic control and EFI needs to have a fast idle button and a hot start lever? Every other EFI vehicle I have driven / ridden needs no manual controls because the ECU adjusts to suit the conditions on hand. I think it is ridiculous that I still have manual controls to operate when the ECU should be dealing with that. The extra controls are just more complexity and things to stop working along with the hot start lever being susceptible to crash damage. My GSXR1K works fine with no extra buttons or levers, so why does my MX bike need them?

There, now I feel better...:thumbsup:

Mark

You are dealing with the most basic of EFI here, that is why it still has manual controls.

Just another reason as to why I bought the 09 KXF450

Just another reason as to why I bought the 09 KXF450

Isn't there a choke on that bike, too?

I know there's one on the CRF450 also.

Also, having to kick start it, the EFI system probably doesn't have enough time to calculate the mixture between the moment you kick and the moment it has to inject the fuel, as an electric started vehicle can take a few revolutions before starting.

Isn't there a choke on that bike, too?

I know there's one on the CRF450 also.

Also, having to kick start it, the EFI system probably doesn't have enough time to calculate the mixture between the moment you kick and the moment it has to inject the fuel, as an electric started vehicle can take a few revolutions before starting.

The EFI system has to be powered up to start the bike, it does this after you kick it a few times and get the capacitor below the TB energized.

Also, having to kick start it, the EFI system probably doesn't have enough time to calculate the mixture between the moment you kick and the moment it has to inject the fuel, as an electric started vehicle can take a few revolutions before starting.

The EFI should be more than fast enough to react to the engine as you kick it over, because it has to react to engine rpm changes that occur much faster than you can possibly kick.

Aaron, I am not sure why you would consider this EFI any less sophisticated than most sport bike EFI systems, they all run similar numbers of sensors and are open loop systems. After the capacitor is charged and the ECU juiced up, it should easily be able to identify a cold start condition or a hot start condition after a hot shut down or crash and find the appropriate point on the map to start easily. Perhaps it is simply an issue of the maps not being sorted for the cold and hot starting conditions?

It just seems so rudimentary to me to be able to deal with these issues in any EFI system at this point in the technology development.

Mark

So I bought a leftover 08 a month ago and managed to get a few rides on it before the season really came to a halt. Great bike and I am very happy with it overall. I have one complaint on the EFI, though.

Why is it that a bike with full electronic control and EFI needs to have a fast idle button and a hot start lever? Every other EFI vehicle I have driven / ridden needs no manual controls because the ECU adjusts to suit the conditions on hand. I think it is ridiculous that I still have manual controls to operate when the ECU should be dealing with that. The extra controls are just more complexity and things to stop working along with the hot start lever being susceptible to crash damage. My GSXR1K works fine with no extra buttons or levers, so why does my MX bike need them?

There, now I feel better...:thumbsup:

Mark

I come from the car world and I know nothing about the sport bike world, but cars use one more actuator, generally called a idle speed control actuator. This actuator gives the engine a fast idle in the AM and handles other duties once the car is warm. I think I would rather pull the choke out then add more wires and another actuator to the mix.

I come from the car world and I know nothing about the sport bike world, but cars use one more actuator, generally called a idle speed control actuator. This actuator gives the engine a fast idle in the AM and handles other duties once the car is warm. I think I would rather pull the choke out then add more wires and another actuator to the mix.

This is what I was talking about with rudimentary. The choke is more or less a fast idle, and hot start does the same basic thing.

I come from the car world and I know nothing about the sport bike world, but cars use one more actuator, generally called a idle speed control actuator. This actuator gives the engine a fast idle in the AM and handles other duties once the car is warm. I think I would rather pull the choke out then add more wires and another actuator to the mix.

That is a fair point. I was thinking of just the mixture enrichment required for a cold start, not the faster idle. So, I can see the point to the fast idle button with that in mind.

The hot start still does not make sense, because it is only there to prevent flooding of a hot engine. Since the EFI controls all fuel into the engine, it can simply add less fuel during a hot start. If the fueling was dependent on airflow as on a carb, then the hot start makes sense. But that should not be the case for EFI. Anybody have any more info on the hot start lever function with EFI?

Do the 09 Honda and Kawi also still use a hot start lever? I know the Honda has the fast idle button, how about the Kawi?

Mark

That is a fair point. I was thinking of just the mixture enrichment required for a cold start, not the faster idle. So, I can see the point to the fast idle button with that in mind.

The hot start still does not make sense, because it is only there to prevent flooding of a hot engine. Since the EFI controls all fuel into the engine, it can simply add less fuel during a hot start. If the fueling was dependent on airflow as on a carb, then the hot start makes sense. But that should not be the case for EFI. Anybody have any more info on the hot start lever function with EFI?

Do the 09 Honda and Kawi also still use a hot start lever? I know the Honda has the fast idle button, how about the Kawi?

Mark

My 09 KX450F doesn't have a hot start button but it doese have the fast idle buton.:moon::thumbsup:

That is a fair point. I was thinking of just the mixture enrichment required for a cold start, not the faster idle. So, I can see the point to the fast idle button with that in mind.

The hot start still does not make sense, because it is only there to prevent flooding of a hot engine. Since the EFI controls all fuel into the engine, it can simply add less fuel during a hot start. If the fueling was dependent on airflow as on a carb, then the hot start makes sense. But that should not be the case for EFI. Anybody have any more info on the hot start lever function with EFI?

Do the 09 Honda and Kawi also still use a hot start lever? I know the Honda has the fast idle button, how about the Kawi?

Mark

The hot start and fast idle do the same thing on the Suzuki.

dnt backflip it lol... it will shut off in midair

dnt backflip it lol... it will shut off in midair

don't worry, there is a timer on the tip over switch system.. you would have to be upside down for more than ten seconds to have stalling issues.... and at that point I think you would have other issues :thumbsup:

oh and the fast idle(choke) knob is used to eliminate the cost, complexity and weight of the idle air control motor that is used on the gsxr1000

keep in mind its a dirt bike... having a servo to control a leak jet is not a great idea. Plus when was the last time you hucked your Gixxer into the ground.

A simple cable is just that.... simple

This system is a total loss electrical system and it runs in open loop. What that means is that it's magneto has to generate enough voltage to run the system without a battery and since it does not have an oxygen sensor, it uses engine coolant temperature to tell the pcm what fuel and timing curve to give it. If it were a closed loop system, it would have an oxygen sensor and run in open loop until it reached a certain temperature go into "Closed Loop" and then use the oxygen sensor to tell the pcm how much oxygen is in the exhaust and make immediate adjustments in relation to the amount of oxygen in the exhaust. This is commonly called a "Feedback" system. Most oxygen sensors have to reach a certain temperature to work correctly, thus the open loop routine until the desired temperature is achieved. Cold engines need more air and fuel than warm engines. The fuel is put in by the injector('s) controlled by the pcm. On cars, the extra air and idle speed are controlled by the pcm and it uses an actuator called an idle air controller to adjust the amount of air going into the engine at idle and low speeds. Since the Suzuki has no battery to store power and for the simplicity, it has a manual means to let more air in while cold and in the event of a crash or a condition that has let excess fuel build up in the cylinder, it has a lever to allow more air in to clear out the cylinder and promote easier starting. There are many manifestations of this operating strategy and this explanation is the most simplictic that I could think of. I hope this helps people understand it and not confuse them. Do not be afraid of engine management systems. They have been around for quite sometime now and are designed to let you have your cake and eat it too. It just takes a little understanding at first.

Good Luck!

STS.

Cold engines need more air and fuel than warm engines.

<snip>

Do not be afraid of engine management systems. They have been around for quite sometime now and are designed to let you have your cake and eat it too. It just takes a little understanding at first.

Good Luck!

STS.

Cold engines do not need more air, just extra fuel. The choke circuit on a carb simply dumps in more fuel to keep the fire lit while cold. At least it does on any carb I have worked on, is the FCR carb any different? I wanted to know why this couldn't be handled completely by the ECU. Same for the hot start, the extra air put in by a carb hot start circuit is simply a way to lean out the mixture, since the carb cannot alter the amount of fuel it is putting in. Again, the ECU should be able to handle this without rider input.

I am not afraid of EFI, on the contrary I think it is a great step forward. I did buy the first EFI bike available, after all. I just wanted to know why Suzuki went halfway and didn't do the whole job. They also have the most experience with EFI on street bikes among the big 4, so it's not like this is new for them. And Kawi managed to do away with the hot start lever with their EFI bike... I don't want an idle air valve as someone suggested. I am in favor of simplicity and wanted to know why I needed a cold start button and a hot start lever, both of which are just more stuff to go wrong.

Don't get me wrong, I am not criticising EFI at all, just the way Suzuki implemented it. After experiencing the fantastic off idle control and smooth power of the RMZ I never want a carb again. I would just like to toss the cold start button and hot start lever along with the jets.

Mark

Cold engines do not need more air, just extra fuel.

Some will disagree with you and most IAC systems do idle up when cold to prevent stumbling but you're on the right track. The bottom line is, things work better when the engine gets the right amount fuel and air for the condition. I'm all for mass air flow and air fuel ratio sensors. Shielding the O2 sensor to keep the outside air reference from becoming plugged or contaminated by water will be a good trick though. It will be interesting to see how things develop.

Good Luck!

STS.

This system is a total loss electrical system and it runs in open loop. What that means is that it's magneto has to generate enough voltage to run the system without a battery

STS.

You are wrong. It has a big capacitor to help starting.

This system is a total loss electrical system and it runs in open loop. What that means is that it's magneto has to generate enough voltage to run the system without a battery and since it does not have an oxygen sensor, it uses engine coolant temperature to tell the pcm what fuel and timing curve to give it.

Good Luck!

STS.

Did you just make up that terminology? I've always heard it called battery less FI system. Why are you bringing in O2 sensors? Even on cars O2 sensors are not used when starting at any temperatures.

You are wrong. It has a big capacitor to help starting.

The capacitor is below the TB. It gets charged when you kick it that first few times when the bike hasn't been ridden for a while, then that power is used to spin the fuel pump and power the ECU so the bike can start.

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