Suzuki GSF400 Bandit

[tubular]

Newsflash: The B4 is alive and kicking again

Just came up from the garage. Indeed the R20 was damaged, probably from failure of the TachoModule. However I cannot put the blame on this tach input module cause it was not designed or intended for such use. This is merely a small circuit designed to drive older coil driven rev counters. Anyway, I removed fried R20 and soldered a hole through resistor. Actually I soldered two leads and put the resistor on a small board so replacement can be easier if needed again. Hopefully not...

Followed EW's advice and applied Matt_GSXR circuit. The bandit fired up immediately and idled smoothly. Kudos to EWflyer and Matt_GSXR
Maybe it's only my impression but it does seem to startup easier. Maybe a better cranking RPM signal from the new tachinput circuit but definitely a charged battery made the difference. Thanks and kudos to 24c for pointing that too.

Tomorrow I will go for a test ride, same as before, and see how it runs. In fact I just might try to rev it up to red line.

However I am concerned about this notice in the Microsquirt installation guide, where it says that if triggering directly of the coil then connect OPTO IN - to 12V rather than grounding it in order to avoid thermal "meltdown" of components inside the ECU. On the other hand I have already fried something inside the ECU so it won't be the first time Just hope that it will work OK in the long run.

I was wondering however, would it be possible to connect the OPTO IN + to a smaller voltage source (eg to Vref) instead of 12V ? Does less voltage means less thermal punishment of the ECU in this case and is it adequate to trigger the optocoupler? All comments are welcome.

I am also planing to get myself or fabricate a fuel valve that will allow a fuel return line to reservoir without any cutting drilling or welding of the gas tank. Until now I have just tee'd the return fuel line back to the pump inlet but it does get hot -both pump and fuel hoses- and it kind of worries me.

Something like this: http://www.pingelonline.com/powerflo_7310-CH.htm
Actually these guys sell also an adapter plate that fits the bike's tank: http://www.pingelonline.com/powerflo_adapter_plates.htm

So back on the streets. I'll keep you posted.

Thanks and Regards

[EWflyer]

However I am concerned about this notice in the Microsquirt installation guide, where it says that if triggering directly of the coil then connect OPTO IN - to 12V rather than grounding it in order to avoid thermal "meltdown" of components inside the ECU. On the other hand I have already fried something inside the ECU so it won't be the first time Just hope that it will work OK in the long run.

I don't think you should worry. Remember that the silicon diode in the Matt_GSXR circuit is completely blocking the coil's effects out and the 1K ohm resister is drastically limiting the flow of electrical amperage through the circuit. Unless my (very limited) electronics knowledge fails me the situation in the Matt_GSXR circuit boils down to this basic formula: Voltage/resistance=current (a.k.a. amperage). So you're subjecting your Microsquirt to 12volts/1K ohms = 0.012 Amps. I'd put that in the "not a problem" category.

I'm very happy to hear that the Bandit is up and running. Keep us posted.

Greg

[tubular]

Greetings everyone,

Baby was born so I left project aside for a while

Not much happened since last update except the fact that I rearranged the fuel system. Removed fuel pump from underneath airbox. It was receiving too much heat from engine block at that place. Also moved the fuel pressure regulator under the tail. Looks a bit more tidy now but I have hoses (fuel and vacuum) running all over the bike...

So I made up my mind. Up untill now I did the whole project with a basic rule: No permanent changes, in case I had to revert.
Since project is proven to work I will pass the point of no return and proceed in the following mods:
- Fit an intank pump in the bike's reservoir. Heading for a GSXR600 fuel pump which has a relatively low power consumption and also has a built pressure regulator,in order to have a returnless fuel system.
- Gut the MIKUNI CV carbs and adapt an injector pocket on each. I have searched a bit but could not find a TB setup that would fit the Bandit's engine. All are too large in size. So I'll convert the carb bodies. It does not look like I can achieve a good angle for the injector. It will be more or less perpendicular to air flow or with a few degrees (abt 10) angle. A search over the net revealed that it is not that important, especially if you are not after peak performance. We'll see.

Who dares wins!

[tubular]

Time for an update. As I said in previous post I would be attempting some serious modifications on some bike parts.

Well, instead of fitting an intank pump, I preferred to stick with with the fuel pump already used and the adjustable pressure regulator. Why spend extra money to buy something that I already have? And the adjustable pressure regulator can help in the tuning process. Besides that, it seems that there is not enough flat surface at the bottom of the reservoir to fit an intank assembly. But I never got to verify this, maybe it is only my idea.

What I did though, was to fit an extra fuel petcock. The fuel pump inlet is 12mm therefore I needed a fuel petcock of the same diameter for the 12mm fuel hose. Moto Guzzi is using in some of their bikes (eg V11 LeMans) an external fuel pump much similar to what I have, and has a suitable petcock. So I ordered a fuel petcock and tank flange assembly. Drilled the reservoir, fitted the petcock assembly and fixed it with epoxy putty (this jb stuff works really well). The result is something like this:



Uploaded with ImageShack.us

So now I am using the original 8mm petcock as a return line and have a more straightforward fuel system, avoiding constant fuel recirculation and fuel overheating that was observed in my previous returnless fuel sytem installation.

The second and most important modification was fitting injector pockets on the carb bodies. I had to remove the float bowl covers and all internal carb parts, leaving nothing but the slides. Then started cutting and drilling. The most comfortable place to drill was actually to enlarge the small hole for the idle mixture screw. So I took a deep breath and started drilling. The result was fairly good:



Uploaded with ImageShack.us



Uploaded with ImageShack.us

Then I had to cut the CBR airbox injector housing assembly into four separate pieces and attach each one on a carb body. Again used plenty of jb epoxy putty to fix in place.



Uploaded with ImageShack.us



Uploaded with ImageShack.us

As you can see, the injectors are not at all angled towards the engine intake. They have a small angle aiming towards the throttle plate. Could not do much about it as this was due to the design of the carb body. But it actually works good. My theory is that the fuel spray hits on the throttle plate, then atomizes even more and redirected to the engine intake. Air being drawn into cylinder takes care of the rest. But I think I might have been a bit lucky on this point because it just happened that I am using injectors with a wide spray pattern. I am using the secondary set of injectors of a CBR600RR that are mounted at the airbox. Maybe these are more of a "shower" type injectors than the primary units of the same bike. Flow rate is the same but body colors are different (primary set is pink and secondary set is dark green), so that makes me think that these are not the same. Anyway I am only speculating but, if I was using the primary set of injectors or some other type of injectors with a more "focused" beam of fuel, this setup would not work good or even at all. I will try it out sometime if I find some other injectors.

The whole thing mounted on the engine:



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What d'ya think???

I did not put back on the airbox and in the free space I mounted the Microsquirt, the fuel pressure regulator, the MAP sensor and pretty much everything. Fuel pump and fuel filter are also attached on the throttle (once carb) bodies and the whole thing looks much more compact now. No more fuel lines running all over the bike! Even the side covers can fit back in place.

Weather has not been very helpfull to go out for a ride. I am really curious to see if the VE tables of the previous setup will still be usable now!

So, Santa dropped by a couple of days earlier and brought me a nice present!!!!

My warmest wishes to everyone. May in the New Year we become better men and this world a better place to live.

[EWflyer]

I like the new configuration, hope it works well.

I think your placement of the injectors is about the best you could hope for in a carb-to-throttlebody conversion. It seems to me that it's a good choice to have the injectors pointed upward, and it's also good that the injectors will hit the side of the throttle plates that angles toward (into) the engine, and most importantly I like that the injectors are very close to the point in the throttlebody bore where both the carb slide-plate and throttle plate open up. That should provide for a nice area of flow that is both high speed and turbulent for good mixing of the injected fuel.

When you get it up and running well you should do a video of the whole thing like I did. I'd like to see it all explained in video and to see/hear it run. Keep us posted on your progress.

[motthomas]

Nice work mate! I really hope this works well for you. Im looking to do the same kind of thing as you did first as a temporary setup on my CBR250RR and then if it works Ill be modifying a set of GSR400 throttle bodies.
What pump and pressure regulator did you end up using?

[tubular]

...What pump and pressure regulator did you end up using?

Hi,

I am still using the same stuff I bought originally for the project. This would be:

-an external in-line fuel pump (automotive type replacement for bosch part # 0580464070)
-an adjustable fuel pressure regulator (1 - 5 bar)

The exact parts are:

fuel pump: http://www.fuelpumpsonline.co.uk/sytec- ... 1931-p.asp
fuel pressure regulator: http://www.fuelpumpsonline.co.uk/fse-ad ... 1901-p.asp

The important thing before going out and get yourself a fuel pump is to check your bike's electric power budget. A fuel pump that draws a lot of current and exceeds the capacity of what the bike's electrical system can produce, will not be a sufficient solution.

A possible alternative would be an in-tank fuel pump/pressure reg assembly from a GSXR600. Or if you can source GSR400 TBs (this thing is almost impossible to find - at least where I live and) then most likely you can source the fuel pump/pressure reg assy as well. This would give you a perfect match and would save you space and from a lot of hose routing, making your project look nice and tidy.

[motthomas]

Thanks mate! The current draw of the fuel pump has been my biggest concern alright. To try get an idea what I can use I have been looking at 125 2stroke projects as they would have a similar problem with current draw. I have a short list of cheap pumps that I will test out as part of the project.

[Tiberius]

Hi

I've been planning on converting my CB-1 for a while. Now I've startet buying parts and ended up getting the injection assembly (TB's, TPS, injectors, FPR, rail, lines...) off a Triumph TT600. Those are nice because they are really individual TB's and can be spaced as needed.

Now I came across a question: The FPR on the assembly needs a vacuum reference. I don't have the Triumphs Workshop manual so I couln't find out where the vaccum hose goes bu this puzzles me a bit. How did you solve this? is your FPR vacuum referenced?

cheers

Kevin

[tubular]

Kevin,

I just t'eed together the vacuum port from each separate carb body (originally intended for carb balancing) in one hose. Fed the MAP sensor and pressure regulator from this pipe. Got a decent MAP signal and it works good for the FPR I suppose. Now the thing is that I am not really sure if having the FPR vacuum referenced or just connected to Patm, will have any noticeable effect on our small engines. For quite some time I had the bike running with the FPR on atmospheric pressure by mistake(obviously I forgot to connect the vacuum hose during the numerous assemblies/dissasemblies). Did not observe any difference, but I must admit that the bike was in setup/tuning status at that time (actually still is...). I did not get into the subject further though. Surely somebody knows a few things more about it.

I do have one question though. You are working on Triumph TT600 TB's etc etc. The TT600 TB have no injector pockets. How do you intend to mount the injectors?