EFI yz 450???


18 replies to this topic
  • moto4life

Posted August 23, 2006 - 06:28 PM

#1

Was just wondering if anyone has herd if the :ride: new 07 YZ450 will have EFI :thumbsup: :applause: ??

  • Jaycycle

Posted August 23, 2006 - 06:46 PM

#2

No it doesn't. But possibly in 08?

  • BergArabia

Posted August 23, 2006 - 11:11 PM

#3

Well the EFI would solve the jetting issues for guys with 6 thumbs like me.
next we need self adjusting suspensions.. :thumbsup:

I wonder if the EFI would affect the weight on the bike, including weight distribution?

  • Fastest1

Posted August 24, 2006 - 05:00 AM

#4

I wonder if the EFI would affect the weight on the bike, including weight distribution?

No it is pretty light and they could place the necessary items as low as they wanted. Probably wouldnt weigh more than a carb. It wont make it easier unless you have the correct maps for your alt,temp and humidity. Would still beat the carb in performance.

  • vznx1w

Posted August 24, 2006 - 06:02 AM

#5

I have worked for a leading manufacturer of automotive and motorcycle EFI systems for 20 years. I say with all confidence that EFI WILL add weight to the bike and WILL NOT increase peak power. It will also eliminate the individual's ability to tune his own bike to local conditions/preferences without adding even more weight (a Power Commander type aftermarket module).

On the plus side:
1. It would eliminate the occasional bogging/power loss that can result from fuel sloshing in the carb float bowl, during severe whoops or hard landings,
2. It could--if properly done--finally eliminate the dreaded bog that some experience when wacking the throttle open at low RPM. But, the latest bikes have reduced the bog problem to the point that only a small rider adjustment is required to avoid bogging.

Detail:
Removing the carb doesn't save appreciable weight because you replace it with a throttle-body. Then you ADD the following components:

Fuel pump (probably up high on the bike)

Fuel pressure regulator

Fuel injector(s)--maybe two (current sport bikes use two injectors per cylinder)

Fuel filter and high pressure fuel lines must be added.

The bikes electrical system must be beefed-up to provide the power for the fuel pump and injectors, either by:
1. Adding a battery
2. Adding a large charging coil to the mag and fairly large rectifier to change the AC output into the DC power required by the EFI system.

No free lunch fellas.

  • barch88

Posted August 24, 2006 - 06:15 AM

#6

Was just wondering if anyone has herd if the :ride: new 07 YZ450 will have EFI :thumbsup: :applause: ??

No, it don't.

  • Ga426owner

Posted August 24, 2006 - 06:28 AM

#7

I have worked for a leading manufacturer of automotive and motorcycle EFI systems for 20 years. I say with all confidence that EFI WILL add weight to the bike and WILL NOT increase peak power. It will also eliminate the individual's ability to tune his own bike to local conditions/preferences without adding even more weight (a Power Commander type aftermarket module).

On the plus side:
1. It would eliminate the occasional bogging/power loss that can result from fuel sloshing in the carb float bowl, during severe whoops or hard landings,
2. It could--if properly done--finally eliminate the dreaded bog that some experience when wacking the throttle open at low RPM. But, the latest bikes have reduced the bog problem to the point that only a small rider adjustment is required to avoid bogging.

Detail:
Removing the carb doesn't save appreciable weight because you replace it with a throttle-body. Then you ADD the following components:

Fuel pump (probably up high on the bike)

Fuel pressure regulator

Fuel injector(s)--maybe two (current sport bikes use two injectors per cylinder)

Fuel filter and high pressure fuel lines must be added.

The bikes electrical system must be beefed-up to provide the power for the fuel pump and injectors, either by:
1. Adding a battery
2. Adding a large charging coil to the mag and fairly large rectifier to change the AC output into the DC power required by the EFI system.

No free lunch fellas.



totally agree.........

  • grayracer513

Posted August 24, 2006 - 01:49 PM

#8

I've also spent a large part of the last 30 years working on, with, and around EFI systems, both OEM and aftermarket, and I disagree to some extent, not so much with the technical facts as with the negativity expressed.

I say with all confidence that EFI WILL add weight to the bike and WILL NOT increase peak power. It will also eliminate the individual's ability to tune his own bike to local conditions/preferences without adding even more weight (a Power Commander type aftermarket module).

Given a perfectly jetted carb, it is true that EFI offers no peak power improvement. It is even true that an overly simplistic FI setup cannot match the across the board performance of a totally perfected carburetor at all throttle and load conditions. Carbs, depending as they do on the actual flow of air through the instrument to deliver the fuel, are capable of adapting to a wide range of such conditions on its own. But, let any of a number of environmental variables change, and you no longer have a perfectly set up carb. User intervention is required to correct for such changes.

Under these circumstances, a good, sophisticated system can and will adapt on its own to changes in altitude and temperature automatically. As for user tunability, we could assume from the fact that the current street bikes are not trimmable without an added on box that production racing bikes would not be either, but that's a fact not in evidence at this point, and Yamaha and others may very well include that functionality. Current sport bikes are required by law not to have such user adjustability in order to comply with smog laws. Besides, Power Commanders don't weigh much, and I don't see it being that hard for someone actually capable of jetting a carburetor to deal with learning how to trim 3-D fuel curves.

On the plus side:
1. It would eliminate the occasional bogging/power loss that can result from fuel sloshing in the carb float bowl, during severe whoops or hard landings,
2. It could--if properly done--finally eliminate the dreaded bog that some experience when wacking the throttle open at low RPM. But, the latest bikes have reduced the bog problem to the point that only a small rider adjustment is required to avoid bogging.

It will also pretty much eliminate flooding and other hot start issues. In fact, the bike will operate in any position that will maintain a flow of fuel into the pump just as well as it will in the upright. The fact that an FI unit is not dependent on air flow for fuel metering means that the engineer can make the unit deliver what fuel he wants just whenever he wants it, regardless of the behavior of the air in the venturi.

Detail:
Removing the carb doesn't save appreciable weight because you replace it with a throttle-body. Then you ADD the following components:

Fuel pump (probably up high on the bike)

Fuel pressure regulator

Fuel injector(s)--maybe two (current sport bikes use two injectors per cylinder)

The fuel pump can actually be mounted anywhere, but it usually is simpler to put it in, on or very near the fuel tank. Even so, the fuel pump for a Z28 Camaro weighs about a pound and a half, and is about half the size of a Red Bull can. A pump suitable to satisfy a 27 cubic inch engine as oppossed to a 350 C.I. engine should be much smaller and lighter. The fuel pressure regulator for a Z28 is heavy enough to require two first class stamps, but probably not 3.

Sport bikes have two injectors to solve a problem that an MX bike will not necessarily have; that of being capable of satisfying the needs of a 170 hp/liter at full throttle while still being able to meet emissions requirements and deliver good clean driveability and fuel economy. The ZR-1 Corvette engine used this same technique to have two different fuel spray patterns in the same engine. But there may well be no need for that on a race bike.

And, a lot of the additional weight can be offset by ditching the carb itself for a throttle/injector assembly that will be far lighter than an FCR, and can even be made mostly of plastic.

Fuel filter and high pressure fuel lines must be added.

True, but this adds only expense, very little weight, or even complexity.

The bikes electrical system must be beefed-up to provide the power for the fuel pump and injectors, either by:
1. Adding a battery
2. Adding a large charging coil to the mag and fairly large rectifier to change the AC output into the DC power required by the EFI system.

All solid state electronics are DC devices, including the current typical CDI units, yet no rectifier separate from that built into the unit itself is incorporated into the ignition of most MX bikes. The fuel pump could run off of AC without a rectifier, and the DC requirements of the injectors could be handled by the control module.

Some of the current EFI systems being tested use neither a battery or a capacitor for start up fuel pressure. The EFI CRF450 has a mechanical pump incorporated into the kick starter assembly.

I think that if Yamaha puts the resources that they have available to them into the project that the overall performance improvement will be well worth it, and the weight penalty will be no more than 3 pounds, tops. Not a free lunch, but it should be both tasty and filling.

  • Jaycycle

Posted August 24, 2006 - 02:08 PM

#9

In fact, the bike will operate in any position that will maintain a flow of fuel into the pump just as well as it will in the upright. The fact that an FI unit is not dependent on air flow for fuel metering means that the engineer can make the unit deliver what fuel he wants just whenever he wants it, regardless of the behavior of the air in the venturi.


So does that mean you wouldn't need a gas cap vent hose? Would it just be a gas cap? orrr no wait nvm then it would just suck the tank in, right?

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  • grayracer513

Posted August 24, 2006 - 03:09 PM

#10

So does that mean you wouldn't need a gas cap vent hose? Would it just be a gas cap? orrr no wait nvm then it would just suck the tank in, right?

I'm not sure how you got there from the quote you posted, but no, the fuel tank will still need a vent.

  • Jaycycle

Posted August 24, 2006 - 03:45 PM

#11

Ahh nvm I'm just stupid and trying to under stand more about FI.


Im thinking over my head :thumbsup: .

  • almostinvincible119

Posted August 24, 2006 - 04:25 PM

#12

Gray...you should write a huge ass book of Q&A's on all things relatively associated with motocross bikes.

  • barch88

Posted August 24, 2006 - 04:42 PM

#13

I say Grayracer for President. :thumbsup:

  • Jaycycle

Posted August 24, 2006 - 05:17 PM

#14

You know I think barch is right. He knows EVERYTHING. For instance I just did two searches and what I was looking for he answered. One was about porting and polishing and I forget the other.


Bosch you better look out! Gray is on his way. :thumbsup:

But really he should be a mod or something.

  • vznx1w

Posted August 24, 2006 - 06:28 PM

#15

Hats Off to Older and YZer for a very thoughtful and well reasoned rebutall to my comments. He rightly detected my somewhat negative attitude about EFI on race bikes.

Bottom line:
Street EFI exists because engines couldn't otherwise meet emissions standards with acceptable performance.

Racing EFI is generally most valuable in events that mandate fuel consumption limits; although EFI doesn't increase peak power it can eliminate the ocassional overrichness that occurs with carb setups--making carbs less fuel efficient.

For MX bikes, I'm just not sure that the benefits of EFI (even as stated by Older & YZer) are worth the cost. This could change if the government forces EFI by drastically tightening off-road emission standards. Until then, the same amount of money that adds (x) pounds of EFI components to our bikes, could be spent on lightweight materials that would actually reduce weight.

For me, the key question is: will the OEMs allow us to tune their systems? If we are stuck with whatever fuel map that they provide, then everytime we want to change a pipe or camshaft we will be forced to use a Power Commander type device, which adds weight and potential failure modes, while not allowing complete control of the tuning variables.

I agree with the technical points put forth by Older and YZer, but respectfully remain a bit negative about giving up my carb and box full of brass.


Steve
06 YZ450F
01 YZ426F
00 SV650
83 GS1100E

  • almostinvincible119

Posted August 25, 2006 - 04:45 AM

#16

Since the motorcycle isn't street legal and doesn't have to meet such strict emission standards as one that is, I think that the factories will realize this, just like the adaptability of other aftermarket accessories. Think about a truck or car, you buy a superchip, hyperchip, or whatever other kind of power curve selector made and you can change things from fuel consumption to horsepower. While, when using the high hp mode, you sacrifice fuel efficiency, and vice versa, but this wouldn't be a problem on a dirt bike. Unless you want to just save money, and if thats the case, you shouldn't be racing performance motorcycles.

  • grayracer513

Posted August 25, 2006 - 08:29 AM

#17

Bottom line:
Street EFI exists because engines couldn't otherwise meet emissions standards with acceptable performance....

For me, the key question is: will the OEMs allow us to tune their systems? If we are stuck with whatever fuel map that they provide, then everytime we want to change a pipe or camshaft we will be forced to use a Power Commander type device, which adds weight and potential failure modes, while not allowing complete control of the tuning variables.

I agree with the technical points put forth by Older and YZer, but respectfully remain a bit negative about giving up my carb and box full of brass.

You make some good points, Steve. Guys like yourself who are comfortable and accomplished in carb tuning are understandably reluctant to embrace, and learn from scratch, something completely new when there isn't a compellingly significant apparent benefit.

But consider: (Let me preface this by saying that I understand that advances in camshaft design and in electronic timing controls also contribute to what I'm going to say).

Compare the performance of a 1970 LT-1 powered Z28 with that of a 1997 model (we'll ignore the newer ones so that we're comparing two versions of the same basic engine). The '70 model produced about 300 net horsepower (if measured by today's rating methods), and would do a standing quarter mile in the high 13's, and had a top speed of perhaps 130 as delivered. It also had rather poor idle qualities, got about 12 mpg, ate spark plugs like popcorn, and barely passed the smog requirements in place at the time.

By contrast, the 1997 model produced about 300 net hp, and would run high 13's in the quarter, stock. But, it topped out at just over 150. Furthermore, it was capable of 25 mpg on the highway if driven prudently, will run for multiple years on the same set of plugs, and the air that comes out of the tail pipe is nearly cleaner than what went into the air cleaner. And on top of that, it idles like a sewing machine with the same camshaft that lets it run to 6000 rpm+. The engine runs so smoothly that the same power plant was used in Caprice station wagons and Cadillac Fleetwoods (the Fleetwood was a rear wheel drive, so the Northstar wasn't suitable) and no one knew it wasn't a luxury car engine.

You could probably make some fairly sound arguments that the performance improvements could have been made with a carb. I don't think you can convince me, but it would be a good discussion, I'm sure. In fairness, an automotive V8 with port EFI can take advantage of one performance improvement that doesn't really apply to a motorcycle; an open plenum intake manifold. These can't be used with a carb without suffering serious low speed performance issues, whereas moving the injector close to the valve gets around the entire problem. Motorcycle engines already have extremely short intake tracts, so the comparison between carbs and FI is a little more even.

But one thing is certain. The ability to morph from a high powered Mr. Hyde back into a gentlemanly Dr. Jekyl just by backing off and upshifting, as EFI can do, is beyond a carburetor's capabilities, IMO.

  • grayracer513

Posted August 25, 2006 - 08:31 AM

#18

Bosch you better look out! Gray is on his way. :thumbsup:

Was that nice?

  • Jaycycle

Posted August 25, 2006 - 08:38 AM

#19

Was that nice?

Was trying to be?





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