Carb EFI Conversion: VM or CV?

[GSX1100 dreamn]

Hi 93 Bandit,

To answer your question. Yes I cut another ignition cover to extend the original to cover the trigger wheel, not pretty but works for now.
As for the mounting bracket I don't have anymore detail pictures but it was a piece of scrap stainless steel I cut to shape and bolted to the base plate and tapped to mount the pickup.
But also I am still running the Kat ignition setup (does nothing) it was a backup if I needed it when first starting up the EFI, ideally I should pull out the Kat pickup and remount the trigger wheel and pickup further in so I can also use original cover.
Your correct I chose the 1250 Bandit as for capacity it was all but the same as my 1260 Kat so fueling was always going to be very close from start and it is. Otherwise you have to spend $$$/time on a dyno to map the ECU for fuel and if you run it ignition. My o2 sensor is my best friend whether for cabys or EFI it just takes the guess work out of what the mixture is.

Just a few thoughts on setup,

I understand you want to 'convert' carbys to house injectors for that standard look but unless you create the injector angle that a throttle body has you will have very poor fuel atomisation thus negating any benefit/improvement you would normally gain with EFI. Ideally you should get an EFI system up and running reliably with throttle bodies and then once you are happy then muck about with these converted carbys then atleast you know any problems are related to these items and not the new EFI setup.

Another problem is electric power generation as in you will use alot (engine cranking/fuel pump/injectors/lights/ignition) generally more than what the original system was ever meant to cope with, this will need to be addressed. Some EFI converts have changed the rotor/stator from later model higher output bikes whereas others have just added another battery to have a bigger reserve. Either way you have to do something or just keep charging the battery when back home.

Engine management/ECU/computer/ECM call it what you want they all have one and you need to decide what you want to run as it can determine what type of sensors you need to use. After market ECU need to be programmed for all mapping conditions for fuel and if you run it ignition too.

Whereas if you run a factory ECU from a bike that is close to capacity to yours, doesn't just have to be Suzuki it can be any brand and 4cyl then you might be able to get away with only fine tuning the factory mapping, but atleast you have a map to start with and generally close enough to run (like mine).

There are a stack of other things to consider but just a couple very basic ideas for now.

Cheers Andrew.

[93Bandit]

Hi 93 Bandit,

To answer your question. Yes I cut another ignition cover to extend the original to cover the trigger wheel, not pretty but works for now.
As for the mounting bracket I don't have anymore detail pictures but it was a piece of scrap stainless steel I cut to shape and bolted to the base plate and tapped to mount the pickup.
But also I am still running the Kat ignition setup (does nothing) it was a backup if I needed it when first starting up the EFI, ideally I should pull out the Kat pickup and remount the trigger wheel and pickup further in so I can also use original cover.
Your correct I chose the 1250 Bandit as for capacity it was all but the same as my 1260 Kat so fueling was always going to be very close from start and it is. Otherwise you have to spend $$$/time on a dyno to map the ECU for fuel and if you run it ignition. My o2 sensor is my best friend whether for cabys or EFI it just takes the guess work out of what the mixture is.

Just a few thoughts on setup,

I understand you want to 'convert' carbys to house injectors for that standard look but unless you create the injector angle that a throttle body has you will have very poor fuel atomisation thus negating any benefit/improvement you would normally gain with EFI. Ideally you should get an EFI system up and running reliably with throttle bodies and then once you are happy then muck about with these converted carbys then atleast you know any problems are related to these items and not the new EFI setup.

That would be an ideal way to go about things, but that sounds like twice the expense to me. I shouldn't have any problems budgeting for a project like this, but doing it twice seems kind of counter productive, financially anyways. But I see your point.

As for the injector angle; yes it would be 90 degrees if I mounted the injectors vertically, placing the injector nozzle near the needle jet. As for poor fuel atomization due to the angle, I agree. I'm still trying to work that out, I have a few ideas on how to mount the injectors at an angle to help with that, but I'm not too sure how well it'll work. Also, I don't know how the fuel will react at idle with the slide so low over the injector nozzle port. The biggest issue right now is I don't have any injectors to play with, so I don't know how big they are which makes it difficult to see where they will and won't fit. I don't know what injectors I'll use either.

Another problem is electric power generation as in you will use alot (engine cranking/fuel pump/injectors/lights/ignition) generally more than what the original system was ever meant to cope with, this will need to be addressed. Some EFI converts have changed the rotor/stator from later model higher output bikes whereas others have just added another battery to have a bigger reserve. Either way you have to do something or just keep charging the battery when back home.

This is something I've considered as well. I've read about some people rewinding the stator for more output for accessories. I still don't know what power/current demands the EFI system will require, so until I get an idea of it's demands, I won't be able to work out a way to meet that demand. I wouldn't think it would be too much though? I think the highest current draw would be the fuel pump.

Engine management/ECU/computer/ECM call it what you want they all have one and you need to decide what you want to run as it can determine what type of sensors you need to use. After market ECU need to be programmed for all mapping conditions for fuel and if you run it ignition too.

Whereas if you run a factory ECU from a bike that is close to capacity to yours, doesn't just have to be Suzuki it can be any brand and 4cyl then you might be able to get away with only fine tuning the factory mapping, but atleast you have a map to start with and generally close enough to run (like mine).

I intend on using the DIYAutoTune MicroSquirt ECU. There's plenty of support for their ECU's, and even more people using them. I think I could make it work with some trial and error. That's half the fun anyways, right?

There are a stack of other things to consider but just a couple very basic ideas for now.

Cheers Andrew.

I have another question concerning the kaw trigger wheel you used. How did you determine how to time it? I see your thread mentions 7.5 teeth from top dead center, but it doesn't appear there's a way to adjust the timing on your setup? It looks like you filed a nut with the slot so that it would fit in the trigger wheel in the right position, but wouldn't you need a little adjustment ability to get it perfect? Or is the pickup able to move slightly to account for any timing error?

If possible, can you send me some dimensions of the injectors you're using? Like overall length, nozzle diameter, diameter at its widest point?

Also, what kind of idle air control valve setup does your throttle body setup use? If I convert my carbs to EFI, then I'll have to work out the idle air control portion. Will the throttle slides sit high enough at idle to allow easy cold starts? Obviously there wouldn't be an automatic high idle with that set up. Could I just compensate with a rich mixture?

[GSX1100 dreamn]

I find my highest electrical load is sitting at the traffic lights ;engine idling/headlight on/blinker on/ brake light on and you can literally see the voltmeter drop down from the load.

Sorry no readily available injector dimensions they are stuck in the throttle body, but now we revisit my previous post on setup.

You have decided on an ECU so now you need to build around this ECU with sensors that will work with it. Then that will give you the parts you need to buy and then how to mount them based on their specification.

Thats why I used the components on my setup because they suited the Bandit 1250 ECU.

To answer your question on trigger wheel and ISC.
Here is the stock GSX1100 part I modified to mount the trigger wheel.
Item #7

You can see below the slight elongation of the base plate mount which gives me slight movement to line up the 71/2 tooth position.
Timing is done by the ECU so set and forget.

And the picture below shows the ISC, the two lower hoses and the control soleniod on the left.

Hope this helps but remember this setup only suits my Bandit 1250 ECU you need to research the specific components needed to drive your ECU.
Cheers Andrew.

[Spyder]

Hmmm, it would seem to me, that for a GS850, one would look for a GSXR750 setup. (easiest would be an '01-'02)

I have a '95 GSXR that I would like to convert to EFI, and the same setup would likely work out great. The fun part being, FINDING a complete setup. OR, doing a LOT of research, and piecing it together off Ebay... Would also be really nice to have coil over plug as well. Hmmm...

[GSX1100 dreamn]

Hi Spyder,
If your choosing a factory ECU setup for a carby bike best to get one with similar characteristics and capacity.
e.g your GSXR and use a GSXR EFI. ( high rpm power engines similar power delivery)
for 93Bandit with his GS850 look at low to mid range EFI bikes like the GSX-S750.
For me thats why I chose the Bandit 1250 for my 1260 Kat.
Then you can fine tune the ECU to better suit your exact engine needs.
Of course if you are going to use an aftermarket ECU then it dosen't matter in relation to the above except for INJECTOR FLOW CAPACITY SIZE.
Cheers Andrew.

[prostar1316]

Not surprised you couldn't find examples of a successful post conversion. I'm sure there are some, because people have been doing it on old cars since the 90s.
Problem is most new bike engine heads are designed for EFI with short intake runs with steep downhill angles. Very different from a GS with it's horizontal intake.
Building a proper EFI system is only the first part of the conversion project. The long hard part is endless testing and programming a working fuel map.
There needs to be an oxygen sensor located in the best place of the exhaust system.
Starting from point 0, you got a long road ahead before you got a good thing going.

Not sure I agree. V&H have made this easy now that they offer a Dyna type pickup that bolts to a GS engine. The fuel map is easy with closed loop, you just need enough fuel to get it started, then it is straight forward.

I am doing two 1150's now and a 82 Katana after that. I am using Hayabusa Throttle bodies since they are cheap and easy to find.

Good luck

[GSX1100 dreamn]

Not sure I agree. V&H have made this easy now that they offer a Dyna type pickup that bolts to a GS engine. The fuel map is easy with closed loop, you just need enough fuel to get it started, then it is straight forward.

I am doing two 1150's now and a 82 Katana after that. I am using Hayabusa Throttle bodies since they are cheap and easy to find.

Good luck

Hi Prostar1316,
Please post a thread with pictures with your progress and specifications.
Very interested to compare and see your versions of EFI on GS motors.
Cheers Andrew.