gsx-r fuel injection on 79 gs850

[blazinnate]

hey all, i'm trying to figure out what i want to do with my bike this winter. its getting a complete tear down and rebuild, but i've toyed with the idea of either throwing a turbo on, or possibly updating it a bit with a fuel injection system. i guess i'm wondering what throttle bodies would fit closest. i know there's going to be fabrication to be done, and thats not something i'm worried about at all, i'm just wondering what would work best, so any advice is appreciated! thanks in advance.

[Curly]

I've thought about this myself. Biggest issue would be as you said, the throttle bodies. I'd start search forums for port spacing, as that's the hardest to solve. After you find a set that's spaced right I'm guessing the hardest part will be mounting them up. There all larger than a gs's intake ports. Then it's just WB, FP, and MS.

[salty_monk]

Have a read of this.. If your fab skills are really good I suspect you could make your own version

http://roadstercycle.com/yamaha_vmax_fuel_injector_cv_car.htm

[Dogma]

I like that idea of replacing the slide with with an adapter for the injector. It would be pretty straightforward if you have even a small lathe. My brother has one of those... Argh, no time.

I wonder why the deflector under the nozzle is necessary.

[Curly]

To point it towards the intake instead of straight down. Otherwise you'd have gas coming out the intake and igniting. Pretty ingenious, but horrible for dispersal patterns.


P.S. You made me think about this a little more and there are a ton more sub $100 TB setups on ebay than I thought. For a cheap project, you could clamp a pipe in the stock boots and then clamp a silicone reducer onto the pipe, then onto the throttle bodies, no expensive machining required.

TB-$100
FP-$80
WB-$200
MS-$200

$580 for fuel injection doesn't sound too bad at all, although the misc **** is going to eat your budget alive.

[Dogma]

To point it towards the intake instead of straight down. Otherwise you'd have gas coming out the intake and igniting. Pretty ingenious, but horrible for dispersal patterns.

Wouldn't the incoming air just pull it into the intake anyway?

P.S. You made me think about this a little more and there are a ton more sub $100 TB setups on ebay than I thought. For a cheap project, you could clamp a pipe in the stock boots and then clamp a silicone reducer onto the pipe, then onto the throttle bodies, no expensive machining required.

TB-$100
FP-$80
WB-$200
MS-$200

$580 for fuel injection doesn't sound too bad at all, although the misc **** is going to eat your budget alive.

This has been in the back of my head for a long time. I wouldn't want to take apart my favorite bike to work it out though.

[blazinnate]

thanks for the replies! around $500 doesn't sound too bad really. part of me really wants to do this, but part of me just wants to be able to ride next year with no problelms, unlike this year. i probably only had a few weeks of riding out of it because it was one thing after another. i know either route i go its going to be a bit of work, and i've never messed with engines like this, but i'm not too worried about the fab and the technical stuff, i am around plenty of people that will be able to help me out on the stuff i don't know. anyone know what size of TB and injectors i should get? i was thinking somewhere around the gsx-r 750 or so, thoughts?

[86turbodsl]

Slide conversion - terrible idea. The injector needs to spray on the backside of the intake valve. Get regular throttle bodies off ebay. Adapt as necessary. Add crank sensor, fuel pump, temperature sensor, and a microsquirt. Tune as needed. There's your $500 EFI. Don't try and use a factory EFI, you wouldn't be able to calibrate it.

[gmansyz]

Expensive TB's

Hiya all. Man, those are expensive! You got an inline 4 and the '01-'03 GSXR600 has four, individual tb's at 38mm. Or the '00-'03 GSXR750 the same but 42mm. They are like $50 on Ebay and I am using the 38's on my '81 GS11. Just some moderate respacing is all that's needed along with plugging the secondary throttle shaft holes. Then, use the '82-'85 GPZ1100 fuel injection computer and wire harness. The programming is rather close enough and a good way to get your feet wet. Especially if it leaks fuel.
Later on, you can play with the Mega Squirt. And someone named Arttu has done a Turbo bike using the same throttle bodies and the MS.
Just think about it.
Laters
G

[Eliseo Monteverde]

This guy converted his Suzuki DR 350 from the stock carbs to EFI using the megasquirt EFI controller.

http://hackaday.com/2008/04/27/efi-your-motorcycle/

[Curly]

I'm already well versed in MS, that's why I suggested it, I would never want to adapt some GPZ ecu to it. It's simple enough, I don't understand how much simpler you could get or want.

As for injector size, you can change which size you use in MegaTune (I'd suggest Tuner Stuidos though), so any size works, as long as it's big enough in the first place.

[86turbodsl]

Curly, you said FP, WB, and MS. I'm willing to bet most folks don't know you're talking about a fuel pump, wideband sensor setup and microsquirt/megasquirt... it's not that common even after it's been out this long. Just sayin'...

[twotimeGSr]

Questions.. Is this a performance mod.. and if so how much performance? Will gas mileage improve or suffer if driving stayes the same? Can the exhaust stay stock? Is there a mod required to run the computer... stator, etc? and what about reliability..?

thx,

tp

[Curly]

Reliability is all down to how good you and your tune are. If built properly, the MS will last forever. Aside from a bung you'd need to weld in for the wide band, the exhaust could stay the same. I wouldn't think the charging system would suffer with the addition of the wideband, megasquirt and fuel pump, but it'd definitely have to be working at 100%. I don't know how much performance would be added, I know people have added bigger, freer flowing carbs for added power, I'd imagine this would be approx. the same. It should start and respond better however, which would be the real benefit.

86turbodsl, that was more of a list I jotted down for myself, and I know what I'm talking about...sometimes