Author Topic: Fuel injection retrofit  (Read 12636 times)

Offline gpineau

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Re: Fuel injection retrofit
« Reply #60 on: March 11, 2018, 07:47:36 pm »
Got a little work done today.
The throttle body arrived. I measured it for fit and drilled the manifold where it needs to be.
cut some studs from a threaded rod and epoxied them into the plenum. Fit is snug.
Will build up the base platform with epoxy  and seal everything with silicone RTV
I will mount the throttle cable to the side of the plenum coming up from underneath.


1 Connie, 2 Magnas, 1 Yamaha Vstar 950 Touring.
https://motostuff.shutterfly.com/pictures

Offline connie_rider

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Re: Fuel injection retrofit
« Reply #61 on: March 12, 2018, 08:15:48 am »
Sounds like your making progress. Congrat's..
Any more thoughts on the injectors?
I see little room in the runners.
Wondering if you could place them just below the TB {at the rear} so the incoming air does the most to mix?
  {Appears to offer enough room there..}
How will you supply fuel to them?

Ride safe, Ted

Offline gpineau

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Re: Fuel injection retrofit
« Reply #62 on: March 15, 2018, 04:06:56 pm »
Finally some parts are starting to arrive. I got an adjustable fuel  pressure regulator, Fuel pump, injector bungs and some hardware accessories.

My original attempt to epoxy the flange to the manifold plenum failed. It looked great but I gave it a heat test and it fell apart. SO this time I am using JB weld high temp epoxy.  Its ugly but it is working.  Did some measuring and found just the right spot to mount the throttle cable. I used the bracket off an old carburetor.
Worked great....No throttle closed, full throttle full open. 

Not sure yet how I am going to deliver te fuel to the injectors yet. I have ordered a used fuel rail that I will probably cut up  and make it fit my layout.  Got some connectors on order and also ordered the power driver circuits but it will take a month to get here from China. 

So soon I will have the mechanical hardware together and start to work on the electronics.  The programming will, I think be the most difficult because I haven't  given it that much thought.yet.

Photos here https://fuelinjectorproject.shutterfly.com/pictures/40
1 Connie, 2 Magnas, 1 Yamaha Vstar 950 Touring.
https://motostuff.shutterfly.com/pictures

Offline gpineau

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Re: Fuel injection retrofit
« Reply #63 on: March 16, 2018, 02:42:34 pm »
Got some work done on the injector mounting bungs. It's ugly but I think it is going to work.

https://fuelinjectorproject.shutterfly.com/pictures/43
1 Connie, 2 Magnas, 1 Yamaha Vstar 950 Touring.
https://motostuff.shutterfly.com/pictures

Offline gpineau

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Re: Fuel injection retrofit
« Reply #64 on: March 17, 2018, 08:31:06 am »
Wife says I need to sell one of my concours. I think I will keep the 99 and sell the 95. 

The 99 has a starter issue.  spins the motor for a few revs then disengages and need to try again. Its not a big issue since it is an easy starting bike bit I stll want to get it fixed. Any one with experience on this problem.
1 Connie, 2 Magnas, 1 Yamaha Vstar 950 Touring.
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Offline gpineau

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Re: Fuel injection retrofit
« Reply #65 on: March 18, 2018, 03:21:08 pm »
I hate to be the bearer of bad news but I do not think four injector fuel injection can be done for anywhere near $300. Even if you were to grab a used F.I. system from a scrapped bike, it is doubtful the control algorithms would be 'close enough' to correct to work right, and even that would cost more than $300.

But is certainly is an interesting project if you do pursue it. Just as an example, this is a source of both the hardware and software, as well as all the information you need to set up a system should you decide to give it a try:   http://megasquirt.info/

Brian


I am just thinking out loud and as someone that has some experience I hope you read this and have an opinion.

Seems to me that each vehicle whether motorcycle or automobile has a look up table for setting the fuel injector pulse width based on a number of input variables mainly  air flow.
Many of those look up table are available for download for free. But the problem is that they are for a specific vehicle  and are not optimized for you vehicle, temperature, altitude and gasoline quality.  So to use one of those tables would require you to modify it based on your conditions and which injector you are using and any other parameters that are pecular to your bike..  And It would vary based on the fuel you were using and whether you are at sea level or in the mountains.

So what I am getting at is this, why not use a powerful enough processor that you don't need to use a look up table but calculate the pulse width based on input parameters in real time.  You could input your altitude, engine size, injector size and fuel type and have processor calculate the tables for you.  If you are coming down from the mountains the air density could be calculated. If you change fuel you could flip a switch to tell the computer you are using ethanol . I think there are 32 bit processors with enough processing speed to do all this on the fly.

I mean, where did the look up tables come from in the first place...?  They were calculated from a number of input parameters . So why not use the same formulas and do the same calculations but in real time?

Any thoughts?
1 Connie, 2 Magnas, 1 Yamaha Vstar 950 Touring.
https://motostuff.shutterfly.com/pictures

Online B.D.F.

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Re: Fuel injection retrofit
« Reply #66 on: March 18, 2018, 04:24:31 pm »
Well, I really do not know where to start but again, I suggest you go to MegaSquirt and 'study up' on this whole topic. You could start with this page: http://www.megamanual.com/v22manual/mtune.htm

There are two basic methods to control the air / fuel ration on any I.C. engine: speed- density and Alpha-N. Different devices use different systems but motorcycles generally (I believe always) use one induction system per cylinder (one throttle body, one fuel injector, and they are all isolated) and Alpha- N.

Fuel injectors are either open or closed so 'throttling' is accomplished by PWM or pulse width modulation. All fuel injectors have a flow rating, usually in the very odd 'pounds per hour' units. So, the first thing to do is to figure out how much fuel one cylinder of your engine can possibly ever use, under any circumstances and then get a fuel injector that will deliver that amount of fuel if open 85% of the time. Now you have the top RPM and 100% throttle open point of the look- up table.....

Then you construct a look- up table that corresponds with the RPM of the engine and the throttle opening (the X vs Y grid of the table). So the Y axis is engine RPM and the X axis is throttle opening in percentage.

For a rough tune, you can use the air / fuel ration of 12.5:1 (12.5 units of air for every 1 unit of fuel, measured in MASS, not volume). So for a crude example, if the engine's max. RPM is 10,000 RPM, and of course the max throttle opening is 100%, you will set the injector up to have a PWM ON-time long enough to deliver enough fuel to get to that 12.5:1 ratio. So at 5,000 RPM, the PWM On time is one- half of the 10,000 RPM value (assuming 100% throttle opening). Now of course in the real world it is not that simple and there are a LOT of other variables but let us just keep going with our crude example. So you make a look- up table for each, say, 500 RPM increment between 500 RPM and 10,000 RPM. And each 5% increase in throttle from 0 (which is really not zero because you want the engine to idle when the throttle is closed) and 100% open.

Now add to this the nominal air density measured by an absolute air pressure gauge, crank the data from the look- up table through an algorithm that adds / subtracts depending on the air density (for example, altitude changes) and Viola! you know how long to hold the injector open for each 2 engine rotations (remember, a 4- cycle engine has 720 degrees of rotation per cycle, not 360 degrees).

You will also need what is called a Lambda sensor or O2 sensor to know what the engine is really getting regarding fuel delivery. The more O2 in the exhaust, the more lean the mixture, and vice- versa. The nice Lambda sensors are the Bosch 5- wire types, readily available though you do need some electronics to use the data the sensor puts out and put it in some usable, workable form. Again, many devices on the market to do this.

As Lambda sensors are not fast enough to be used in real- time (about 1/12 th second response time), they cannot be used to actually close the control loop. But they are very useful to make minor corrections to the main control algorithm to 'tweak' the mixture for the exact conditions the engine is operating in. That said, they cannot be used even in an speed- density system above 70% throttle opening, at which point you go over to pure look- up table response and forget about any 'real time' input at all. But the Lambda sensor is invaluable, and I believe unreplaceable, for the initial setup of the system, the look- up tables and so forth.

Once you get to that point, you will have to figure out some other things such as injector lag time, hysteresis and a few other (dozen) natty problems but essentially, you will have a running engine.

You will need to sense the crankshaft position (or camshaft) so that you can 1) sense RPM, 2) sense when 'one cycle' is occurring. This is often done with a scheme called the 'missing tooth' scheme, where there are a series of teeth on the crankshaft that an inductive sensor 'watches' pass but there is one tooth missing; typically the number of teeth is 35 (with the one vacant or missing tooth, making 36 even divisions of 10 degrees each).

Now all of this is just the control loop or algorithm. There is still a lot of work to be done regarding venturi size, runner length, injector position and inclination (angle relative to the induction bore) but these are <relatively> small issues if you just want an engine to "work". The good news is that modern injectors such as the 4 and 5 port Bosch's, are actually outstanding regarding atomization of the fuel so putting the injector a bit in the wrong place or position is pretty forgiving.

But all this is just the tip of the iceberg, so to speak. It is a complex and involved subject, even to just do one engine, one time and not even looking for best performance.

The good news is that the PWM nature of fuel injection, along with modern control MPU's, sensors and lots and lots of real- world knowledge make this whole thing much more of a building- block process instead of a solo effort. Which means there are lots of building- block systems as well as knowledge out there to tap into without having to figure all this out.... again. :-) Sorta' like Nicola Tesla did the hard part, all we have to do is follow along and we too can make an induction motor work..... but that first one was a cast- iron B!TCH!  ;D

The first MegaSquirt system I set up used factory injectors in factory T.B.s but I had absolutely no idea what their value was. So I did it 'backwards' and made a look- up table based on 12.5: 1, then varied the size of the injector (in the set- up software) of the MegaSquirt and basically 'backed- out' the injector size. Once that crucial pivot point was reached, the rest was straightforward.

But in all seriousness, if you really want to learn how this stuff works, go read the MegaSquirt manual, concentrating on the Alpha- N part (trust me- that IS the easy one and speed- density is far more complex.... plus it does not work in a multi- induction system such as used on motorcycles).

Best of luck going forward.

Brian

I am just thinking out loud and as someone that has some experience I hope you read this and have an opinion.

Seems to me that each vehicle whether motorcycle or automobile has a look up table for setting the fuel injector pulse width based on a number of input variables mainly  air flow.
Many of those look up table are available for download for free. But the problem is that they are for a specific vehicle  and are not optimized for you vehicle, temperature, altitude and gasoline quality.  So to use one of those tables would require you to modify it based on your conditions and which injector you are using and any other parameters that are pecular to your bike..  And It would vary based on the fuel you were using and whether you are at sea level or in the mountains.

So what I am getting at is this, why not use a powerful enough processor that you don't need to use a look up table but calculate the pulse width based on input parameters in real time.  You could input your altitude, engine size, injector size and fuel type and have processor calculate the tables for you.  If you are coming down from the mountains the air density could be calculated. If you change fuel you could flip a switch to tell the computer you are using ethanol . I think there are 32 bit processors with enough processing speed to do all this on the fly.

I mean, where did the look up tables come from in the first place...?  They were calculated from a number of input parameters . So why not use the same formulas and do the same calculations but in real time?

Any thoughts?
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline gpineau

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Re: Fuel injection retrofit
« Reply #67 on: March 20, 2018, 12:22:21 pm »
Thank you for the information. I have already considered megasquirt and had come to the conclusion although it is a great product I simply cant affort the baseline cost of $1000 just to get started. And the whole Idea is to learn and experiment.

The jist of my question was for an opinion on whether or not a more powerful computer could do all the calculation to generate the correct fuel/air ration "on the fly" rather that using a lookup table and then trimming based on current conditions.

I am going through a "big" remake of the plenum. The first one was problematic when it came to attaching the fuel rail. I just couldn't find a reliable clamp that was hardy enough to stay put under the shake test. 

So I started over with a recycled fuel rail off a 600 CC Honda CBR . it is much more solid and the injectors can be swapped out to a number of injectors that share the same footprint. The injectors are no longer spraying directly into the feeder tubs but rather they are spraying into the plenum just over the feeder tubes.

This is going to set me back about a week.
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Re: Fuel injection retrofit
« Reply #68 on: March 20, 2018, 01:07:56 pm »
Yes, you mentioned the cost of MegaSquirt being too high already; my suggestion was not to buy one but to go to their website and glean the knowledge of how fuel injection systems work. It is the best single source of F.I. information that I know of and the knowledge is entirely free.

Yes, there are sufficiently fast ICUs and even better, MPU's to do real -time calculations with control algorithms. But that is not the reason look- up tables are used; the reason is basically that the entire induction system of any I.C. engine is non- linear and the algorithms would be second order non- linear at that and so very difficult to use for this task. Beyond that, any error, deviation or 'fliers' delivered by any of the sensors would drastically alter the mixture which is absolutely to be avoided and hence, look- up tables are used with rigid parameters around all variables.

Brian

Thank you for the information. I have already considered megasquirt and had come to the conclusion although it is a great product I simply cant affort the baseline cost of $1000 just to get started. And the whole Idea is to learn and experiment.

The jist of my question was for an opinion on whether or not a more powerful computer could do all the calculation to generate the correct fuel/air ration "on the fly" rather that using a lookup table and then trimming based on current conditions.

I am going through a "big" remake of the plenum. The first one was problematic when it came to attaching the fuel rail. I just couldn't find a reliable clamp that was hardy enough to stay put under the shake test. 

So I started over with a recycled fuel rail off a 600 CC Honda CBR . it is much more solid and the injectors can be swapped out to a number of injectors that share the same footprint. The injectors are no longer spraying directly into the feeder tubs but rather they are spraying into the plenum just over the feeder tubes.

This is going to set me back about a week.
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline connie_rider

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Re: Fuel injection retrofit
« Reply #69 on: March 20, 2018, 01:37:01 pm »
So, the first thing to do is to figure out how much fuel one cylinder of your engine can possibly ever use, under any circumstances and then get a fuel injector that will deliver that amount of fuel if open 85% of the time.

Brian. You 2 are way above me on the programming. I won't even try to understand.
I do understand what your getting to with the injector sizing.
But I have 1 question. (Relating this to 1 cylinder)
  When you say if open 85% of the time are you meaning 85% of 1  {360*} rotation,
                                                                                                            or 85% of 1 complete cycle {720*} ??

Ride safe, Ted

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Re: Fuel injection retrofit
« Reply #70 on: March 20, 2018, 02:24:12 pm »
Hey Ted, how are you doing?

One full engine cycle rotation, 720 crankshaft degrees. But it is not the rotation that becomes critical, it is the time available and the precision of the fuel delivered.

A simple example: suppose our imaginary engine turns at a max. speed of 11,000 RPM. That means just under 184 revolutions per second. 184 divided by two is 92, so there are 92 injection cycles per second, and each full engine cycle (720 degrees of crank rotation) will take ~0.011 seconds. Multiply that by .85 (85%) and the window of time to inject one engine cycle's worth of fuel is ~0.009 seconds, or 9 milliseconds. So the injector must be able to inject all the fuel the engine can require at WOT and 11K RPM in 9 milliseconds or less. As injectors are only made in certain incremental sizes, one would just choose the next- larger injector and have the 'right' size for the cylinder / engine in question.

The 85% is not arbitrary either; it is chosen so that there is a comfortable margin for the injector to get dirty, have some pressure fluctuations, have slightly thicker fuel, etc. and still deliver enough fuel. That is why 100% is never used. But neither is, say, 40% for other reasons that become important but are not obvious perhaps.

We talk and think about injectors being open or closed and the transition being instant. In 9 milliseconds, that is close enough to correct to work. But as the engine slows and the throttle is closed, such as at idle, the injector may only be called on to deliver 1/100th of the max. delivery, and in fact, at very small injector delivery rates is where the delivery must be the most accurate. So let's just say that it takes 1/2 millisecond for the injector to open and 1/4 millisecond for the injector to close. While the injector is opening and closing, it is delivering fuel but not the full amount- to keep things simple, let us assume it delivers 1/2 of its fuel capacity during the opening and closing cycles. So for 3/4 of a millisecond, the injector is only providing 1/2 of the fuel we expect but with a 9 millisecond opening, it is not all that critical. But at 1/100th of 9 milliseconds, or .09 milliseconds, we see that we cannot even open and close the injector in that amount of time but also that the opening and closing times become quite critical. That is why a [far bigger than needed] injector is not used, because it becomes almost impossible to control accurately enough at low fuel usage conditions, which is actually the majority of time any road vehicle engine is actually used. That is also why some engines use a pair of injectors per cylinder; a small one used alone at low fuel delivery times, and a larger one that is used when a lot of fuel is needed but extreme precision is not required.  This whole thing is sort of like choosing the right size water valve: a very small one is great for filling eyedroppers but not so good for fighting fires. But the fire hose and valve is not so good for filling eyedroppers. So we have to be careful not only in choosing the correct size injector but also in knowing the lag time (opening and closing) and compensating for that when setting up the mixture tables.

It actually gets much more complicated with a lot of tricky little problems; inside of every large problem, there is a small problem struggling to get out. In controlling the induction system on an engine, there is a little box- full of problems waiting. For example: you are cruising along at low throttle and suddenly open the throttle rapidly. The injectors immediately inject far more fuel, according to the tables and perhaps some external sensors (atmospheric pressure where you are, the temperature, etc.). Let's say the injector suddenly has to provide 30 times as much fuel to the cylinder and it does this. But does all of that additional fuel get into the engine in the first cycle or does some of it coat the induction path walls? So should we inject a little bit extra for, say, the first 5 cycles and then cut back to the 'correct' amount? Or should we inject a bit more for the first 5 cycles, then cut back a little below the 'correct amount' on the next three cycles as that fuel is washed off the port walls, and then inject the 'correct' amount?

Just tuning an already packaged solution that is correctly designed, such as retrofitting the controller on an existing F.I. system, is a challenge. Building one that works reasonably well, at least as well as good carburation, using self- chosen parts, would take some time and effort to be sure.

Brian

So, the first thing to do is to figure out how much fuel one cylinder of your engine can possibly ever use, under any circumstances and then get a fuel injector that will deliver that amount of fuel if open 85% of the time.

Brian. You 2 are way above me on the programming. I won't even try to understand.
I do understand what your getting to with the injector sizing.
But I have 1 question. (Relating this to 1 cylinder)
  When you say if open 85% of the time are you meaning 85% of 1  {360*} rotation,
                                                                                                            or 85% of 1 complete cycle {720*} ??

Ride safe, Ted
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline gpineau

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Re: Fuel injection retrofit
« Reply #71 on: March 20, 2018, 03:05:18 pm »


Just tuning an already packaged solution that is correctly designed, such as retrofitting the controller on an existing F.I. system, is a challenge. Building one that works reasonably well, at least as well as good carburation, using self- chosen parts, would take some time and effort to be sure.

Brian
That is exactly what I am doing. I do not pretend to know everything I need to know starting out. But I intend to finish and when I am done I will know everything I need to know to repeat it on my other bikes. I know it is a challenge and  it gets me excited knowing I am doing something that I have never done before and learn a lot in the process.  I have bee all over megasquirt's manual and  I have read every scrap of information I can find on the internet. I am not getting any smarter but I am beginning to get the big picture forming in my head.

 Its a big complicated project. Mechanical, electrical and programming. I don't expect to be done with this for a very long time. I just scrapped everything I have done so far and started over because I couldn't build a reliable fuel delivery system from the parts and tool I have.  It's a good thing because I learned something. Besides it was really ugly.

I see your point now about using look up tables. If using real time calculations a sensor going haywire could really muck things up,

I have not yet decided to use Alpha-N or speed density.  I am still reading reviews on the different method. I could settle on a hybrid system .....I am not close to that problem yet. I still need to get the manifold, injectors and fuel plumbing done before I begin the electronics. By then I will have a pretty good picture of the the programming that needs done. 
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Re: Fuel injection retrofit
« Reply #72 on: March 20, 2018, 03:30:38 pm »
There really is no choice; speed- density is only practical on plenum based systems. Motorcycles are always based on individual induction ports without a common plenum. Speed- density is not practical if using multi- runnier intakes on relatively small engines due to the pulse effect so that leaves only the multi induction port system using Alpha- N for the control method. It is not a case of which works best, it is a case of achieving good running characteristics for a given type of engine.

A plenum system <could> be used on a motorcycle of course but throttle response will suffer, and it will get worse as one moves away from an in-line four toward something like a Vee engine. The induction paths are too long and vary too much in length from the shortest to the longest. The key here is that while we think of air as having no mass, it really does have some and so moving the T.B. close to the intake port and placing the injector such that it is basically injecting 'downstream' and close to the intake is the preferred way to go.

Of course this all assumes you are trying to build a system that works well (seriously, not sarcastically). If performance and throttle response are not important to you, you can absolutely go the plenum route and use either one or multiple injectors, as you wish. One quasi- fuel injector (more like a 'dribbler') in a large plenum was very common in the early days of electronic fuel injection and was the fore- runner of multi- port injection systems now in common use. They absolutely work.

I know you did not ask but I will offer that the best way to proceed with retrofitting a motorcycle, IMO, would be to get throttle bodies and fuel injectors from an existing design with a similar cylinder size as what you have and adapt it. That way the T.B. and fuel injectors are sized appropriately, located appropriately and have the great advantage of being known to work on a similar application. Then you could concentrate on the code and 'tweaking' of the system to get it to work on your own motorcycles. Just a thought.

Brian


<snip>

I have not yet decided to use Alpha-N or speed density.  I am still reading reviews on the different method. I could settle on a hybrid system .....I am not close to that problem yet. I still need to get the manifold, injectors and fuel plumbing done before I begin the electronics. By then I will have a pretty good picture of the the programming that needs done.
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline gpineau

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Re: Fuel injection retrofit
« Reply #73 on: March 20, 2018, 03:45:52 pm »

I know you did not ask but I will offer that the best way to proceed with retrofitting a motorcycle, IMO, would be to get throttle bodies and fuel injectors from an existing design with a similar cylinder size as what you have and adapt it. That way the T.B. and fuel injectors are sized appropriately, located appropriately and have the great advantage of being known to work on a similar application. Then you could concentrate on the code and 'tweaking' of the system to get it to work on your own motorcycles. Just a thought.

Brian
That is exactly my intent long term. This project is to prove out the electronics and the programming. I am doing it on this V4 Magna because it is a spare bike I use for experiments.

I do not want to do practice surgery on either of my connies. I have been gathering parts already for my connie but I wont touch it until I am through with this project.

And you know if I am successful there are thousands of 1980s-1990s motorcycles sitting in garages and sheds that could be resurrected by duplicating what I am doing.
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Offline connie_rider

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Re: Fuel injection retrofit
« Reply #74 on: March 24, 2018, 09:25:47 am »
Hey Ted, how are you doing?

One full engine cycle rotation, 720 crankshaft degrees. But it is not the rotation that becomes critical, it is the time available and the precision of the fuel delivered.

A simple example: suppose our imaginary etc etc etc,,,,


Hi Brian.   Decided to add a note here.
As I said, I can't touch ya'll on the programming, but can follow/offer thoughts with the build etc.
Interesting discussion...!!

One thing I want to bring us is the sizing of the injectors. You talked about the importance of them not being be too big and got into the pules widths.
But I don't think you went in the basic; why that is so important...
I think the reason for that is; too large of injector isn't precise when small amounts of fuel are required.
    {For most riders, that is probably over 90% of the time)..

Bottom line, he'll need injectors that are capable of supplying enough fuel at WOT/etc, but it is essential to "not" use injectors with too much capability.  Particularly when spraying into a combined Plenum.
        Right???   :o

I'm guessing the size of his Throttle Body is of similar importance?

PS: I tried to PM or Email you several times with no luck. Can you contact me..?

Gpineau; Keep up the good work. I'd love to see you make this workable!!
              I'm still concerned your assembly methods might not hold up for a prototype.
               "But" I also understand why your building the "proto" in this manner.
                   Fingers crossed that you can figure it all out!!  :thumbs:

Ride safe, Ted