Suzuki GSF400 Bandit

tubular
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Suzuki GSF400 Bandit

Post by tubular » Mon May 16, 2011 10:45 am

Suzuki GSF400 Bandit (K -model year 1989)

Once running on carbs, now Microsquirted succesfully :yeah!:

Fuel control only with Microsquirt ECU (code v2.88)
Used DENSO injectors from CBR600 and their fuel rail modified in order to fit in the b4 airbox.
Original bandit MIKUNI carbs are still used as throttle boddies (diaphragm-slide-jet needle assembly removed though)
Bosch automotive type external fuel pump and adjustable fuel pressure regulator to complete the fuel system.
BOSCH CLT sensor installed where the water thermo switch used to be and BOSCH IAT sensor mounted at the airbox. BOSCH O2 sensor with TechEdge wideband controller installed also.
Bike runs on MAP sensor readings only. Still have not managed to mount a TPS somewhere and since things seem to run OK I think I'll pass the TPS stuff.

Started up easy, easier than I expected to be honest :!:

Idles steadily and for the moment it runs lean but the VE and AFR tables are far from optimal or even adequate. No tuning efforts made yet. Will let you know of the outcome.
Last edited by tubular on Fri Aug 05, 2011 10:37 pm, edited 1 time in total.

24c
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Re: Suzuki GSF 400 Bandit

Post by 24c » Mon May 16, 2011 9:02 pm

tubular wrote: Used DENSO injectors from CBR600 and their fuel rail modified in order to fit in the b4 airbox.
Original bandit MIKUNI carbs are still used as throttle bodies (diaphragm-slide-jet needle assembly removed though)
Any pictures or links, as above sounds interesting?

PS Congrats, and I think there is a later version of the B&G 2.88 code too.

tubular
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Re: Suzuki GSF400 Bandit

Post by tubular » Mon May 16, 2011 10:20 pm

Indeed there is a newer sw version out there (3.something I believe). I just used what it came with the ECU. It is working for the moment so I will keep running this and when finished then I'll try updating firmware.

On the other hand if there is a good reason to update now then please let me know. I am totally new at the MS stuff.

Think I have a couple of pics of the injector mounting. Reverting later...
Last edited by tubular on Fri Aug 05, 2011 10:38 pm, edited 1 time in total.

tubular
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Re: Suzuki GSF400 Bandit

Post by tubular » Tue May 17, 2011 11:28 am

Here are a few shots from the injector installation. As I said the injectors and fuel rail came from a Honda CBR600RR and are actually the set of injectors that are mounted on the CBR's airbox (CBR600RR incorporates HONDA's DSFI -Dual Stage Fuel Injection). The fuel rail was modified in order to fit in the airbox. Basically I cut down in length as much as possible and drilled two holes (between injectors 1-2 and 3-4) to attach new fuel inlet and outlet. Then the whole assembly mounted inside the stock airbox on the trumpet air intake. See photos below:

Image

Image

Image

To be honest I had no idea if this was going to work but since it all came down to experimenting I thought I'd give it a try. It is obvious that proper air flow is a thing of the past with this arrangement but until now no negative effects have been observed. Also note that the Microsquirt ECU and the wideband controller are also placed inside the airbox :shock: (at the upper part above the air filter). It was the only place I could place these without having them hanging or exposed. But I am afraid I have reduced the airbox volume quite a bit... :oops: But as I said, until now in the first few test runs the bike is running well.

Using the MS injector test mode I measured the injectors flow rate at about 80 cc/min at approx 15psi. According to MS online manual and calculator it is a good sizing for the bandit's 59HP motor. Maybe a bit on the less side according to paper calculations but hey, my loyal servant is now 22 years old. Think that some of its 59 horses may have retired... :(

For throttle boddies and iar induction I used the bikes assembly of carburetors. The suzuki bandit uses 4x MIKUNI BST33 CV type carburetors. On CV type carburetors the slide and jet needle are not controlled directly from the throttle. These are controlled indirectly from the engine -depending on its load- through a diaphragm/slide/needle assembly. The throttle is connected to a butterfly same as a usual throttle body. So why look for a TB? It is allready there! Simply remove the diaphragm and slide and here you go with a nice TB. I might as well add that removing the diaphragm and slide may not be necessary. Actually the very first injected start up of the engine took place with the slides installed. I removed these to give fuel a clear path to the intake.After tuning is completed I will put them back on and see what happens.

So this is my batch/port hybrid injection setup. When I first started the project, its purpose was more experimental and less of practical use. Back then I said that if engine runs continuously for 30"then project will be succesfull. Today at this point I cannot even remember when it was the last time I heard the engine idling so smooth and sweet. It seems that the bandit may see even more glorious days!!! :yeah!:
Last edited by tubular on Fri Aug 05, 2011 10:39 pm, edited 1 time in total.

tubular
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Re: Suzuki GSF400 Bandit

Post by tubular » Wed Jun 15, 2011 8:22 am

A small update.

The bike is running perfect in the test runs. AFR table is set to stoichiometric (no I don't care about performance) except from high RPM - High load areas were it is set richer. Wideband O2 sensor and autotune is handling the rest.

A small modification performed is a piece of heat resistant material wrapped around the fuel pump. I noticed that the fuel pump is getting too hot. Kind of expected though since the fuel pump is placed underneath the air filter box and receives too much heat from the engine. Also the return fuel line does not go all the way back to the fuel tank. So heat from engine and extra heat from fuel -which in turn gets heated up even more- will most likely result in some kind of problem in the fuel system, so I thought to try applying some kind of protection. Let's see how it works. If not then I will move the fuel pump to the undertail most likely.
Last edited by tubular on Fri Aug 05, 2011 10:39 pm, edited 1 time in total.

EWflyer
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Re: Suzuki GSF 400 Bandit

Post by EWflyer » Wed Jun 15, 2011 9:54 pm

Question for you, I'd like to know how you handled the tach input to the Microsquirt.

Are you using the OPTO input, sensing directly off the coil? Or are you using the bike's VR sensor off the rotor?

I'm trying to use the OPTO input, sensing directly off the coil. I haven't been able to work on my project bike (Kawasaki EX-250) for over a year now but I plan to get back at it soon. Anyway, I haven't been able to come up with a coil sensing setup that works well at RPMs over about 9,000.

If you've got a good solution I'd love to learn about it and copy it on my own project.

EWflyer
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Re: Suzuki GSF 400 Bandit

Post by EWflyer » Wed Jun 15, 2011 10:08 pm

Also, here's an idea for your fuel heat problem.

http://www.summitracing.com/parts/FLX-4130/

This is the smallest fuel cooler I could find when I was building up my EX-250 project. It's small, only 12 inches long and 2 & 1/2 inches tall. I found that on my bike I didn't have room for the whole 12 inches so I took it to a local shop and they shortened it to 6 inches for me by removing the fittings then cutting it shorter and then re-installing the fittings.

Even with it cut down to 6 inches it gets rid of all the heat from the fuel pump. My setup is similar to yours, with no fuel return to the bike's tank. My cooler is mounted right under the bike's air filter so I think it gets a lot of air flow over it.

tubular
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Re: Suzuki GSF400 Bandit

Post by tubular » Thu Jun 16, 2011 10:57 pm

Thanks for fuel cooler tip!

Yes, I am triggering of the coil. To be exact I am triggering off both coils by using a "tacho driver module" (check this: http://trigger-wheels.com/store/contents/en-uk/d31.html ) and scroll down to find the Tacho Driver. I am using the 2-input module which enables me to connect to both coils. I have pushed the bike only to up to 10.000 rpm and haven't noticed any issues. But there are still 4.000 rpm to reach the red line... still not tested.

I am getting a very clear rpm signal but I really have no idea if this related to the tacho module or I am just lucky! I tried it out of curiosity to see if it would work. One thing I observed is that when I have both inputs connected it gives correct RPM, when I have only one input connected I have half of the actual rpm. The b4 has an I4 motor with cylinders 1 & 4 firing off one coil and 2 & 3 on the other. Someone would expect that connecting to one coil would get the actual rpm number since there would be one firing event every 360 deg. Or am totally wrong?
Last edited by tubular on Fri Aug 05, 2011 10:40 pm, edited 1 time in total.

EWflyer
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Re: Suzuki GSF 400 Bandit

Post by EWflyer » Fri Jun 17, 2011 7:29 am

Thank you very much for directing me to the tacho driver module, it looks like just what I need.

I've ordered the 2-input version which they say is good for either 4 or 2 cylinder engines (as long as they have two independent coils, which my motorcycle engine has).

So you just followed the installation instructions (I'm guessing it comes with instructions) and wired the tacho module output to the Microsquirt's OPTO circuit, right?

Thanks again for your help on this.

tubular
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Re: Suzuki GSF400 Bandit

Post by tubular » Fri Jun 17, 2011 8:46 am

I just followed the MS installation manual. The tacho driver module is very simple to install. It is a Y cable so you just connect the single end to the OPTO input of the ECU and the other two to the coils.

Hope it works for you too. And if you need any help I am always around.

Good luck with your project.
Last edited by tubular on Fri Aug 05, 2011 10:40 pm, edited 1 time in total.

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