fuel injection conversion?

hey guys, I have been thinking about converting my xj700 to efi to get rid of those pain in the @$$ carbs. I have searched all over the forum looking for tips and how to, but i haven't found anything really helpful. Does anyone know if there is a kit i can buy cheap as possible. I have searched google and ebay but I would like some helpful tips or thoughts on the process (where to start, cheapest ways, cheapest parts, etc..) i read one post about a guy using old car parts, but i don't have a welder.

Thanks guys.
Big rob

 

EFI conversins are cool, but for older motorcycles they are also an entirely DYI sort of deal. You will be trading one set of headaches for another. My suggestion is to search out forums that are focused on EFI conversions in order to find out more about the process before diving in. At any rate, if you want an inexpensive solution to your fueling problems you'll be better off by rebuilding your carbs.

 

There was a guy on here who converted an XJ700 to EFI using GSXR600 TBs if I recall correctly. Seems like he got the whole thing working then dumped the bike for another project and never wrapped up exactly what went into it. That being said, he walked through a lot of the work he did with it, search it out, it wasn't but maybe 2012 or so.

 

There was another one done years back, but i

Pretty much this. Did a quick search, and there was a reference to a project done by user Pumba, but searching on that username came up blank. IIRC, he got it running, got into an accident, did battle with his insurance company because they wanted to write off the bike (too old), and rebuilt the bike and the injection setup.

edit: it wasn't Pumba, it was SQLGuy, and the thread is here (but the pictures have gone away).

 

I started an EFI ordeal, ended up buying close to $1000 of parts before a family member decided to buy all the parts off of me + the bike that I was doing it to. He wanted a project for him and his son.

I still have 2 reluctor wheels for the gm dis module though.

 

Pumba is the name of the bike, and that's the exact build I was thinking of when I made my comments. http://xjbikes.com/forums/index.php?threads/pumba-the-xj750-project.23014/ The meat of the EFI conversion begins on page 6.

 

(facepalm) You can tell I haven't been here for a while, right?

 

It is a very difficult project to fuel inject these older bikes.

it requires some fancy machining
alot of very custom wiring and computer control systems.
and if you want to do it "right" it also needs several hours of dyno time to set the timing and pulse duration per RPM band

Assuming your time is worth nothing.

your still going to have $1200-$2200 into building and tuning the system.

it may require a bit of time, but $200-$400 for a complete high end carb rebuild is still easier.
(it can be done a little cheaper)

I know carbs can be fussy but setting up an injection system from scatch is not a project for the timid or faint of heart.
on mud bogging truck most of those systems are plug and play upgrades.
you call up the company tell them the motor and crank and cam upgrades, then they send you a kit with the Injector timing
all coming through a new distributor and brain box. plug the new wiring harness into your factory wiring and play.

if you are intrested in fuel injection, you might think about purchasing a newer bike.
the injected liquid cooled motors are built with much tighter tolerances improving HP and performance.

these old bikes are great, they are (relativly) simple and easy to work on.

if a little maintenence is done they can be very reliable and safe.

sometimes it's better to have a working simple bike then to overcomplicate things to the point they no longer work.

(this coming from a fool who is setting up a 750 seca to offroad, (Insert evil laugh here))
(so Please don't think i'm telling you not to do it, I just want you to understand the challenges you are facing)

so.... if you do go ahead with the F.I. conversion i commend your devotion to upgrading an older bike to improving it's funcionality.

as far as improving reliability, i don't truely believe it will, if a fuel pump dies in the middle of the south dakota plains your done.
if a carb acts up, you pop the carbs out strip them reset them and re-install.
and yes, I've seen it done on the side of the road up at lake superior in WI, took the dude about 1/2 hour. (pod filters)

so Good luck in your endevers.

and happy wrenching!!

 

i looked up fuel system for my suzuki sv1000s in the fsm.........90 pages, granted there's lots of pictures but still....

 

wow alright great response to this. The idea of going fuel injected came from me thinking a lot about the carbs, as i still have to take apart the motor and see why i'm not getting good compression all 4 cylinders around 60 psi. So i thought maybe taking the engine apart would be a great time to try FI. I really don't have 1 to 2 grand to drop on it so i guess i'll stick with the carbs. thanks guys for all the help and setting my mind straight.

 

You don't need to take the engine apart to find out why you have low compression. Do a leakdown test. A great time to try F.I. is after you have a engine that you know runs well.

Diagnostics first; then repair, and only then can you work on modifications. People doing things out of order is why folks like us can find $100.00 motorcycles to fix up.

 

100??

wow.. and i thought i was buying cheap at $200.

Hmm, 60 psi..

if they are all at that, it may be rings, not a big deal.
As the man said, checking things first can save time, money and alot of frustration!!!.

Good luck!

and yes, start with a top notch machine then "modify" otherwise you will spend weeks chasing your tail with tuning issues.
if you don't know what you have, you'll never know where the tuning issue is coming from.

 

Picked mine up for $30, no i didn't forget any zeros, a tad over 8600 original miles, and 1 broken screw that kept it from shifting. Thing looked like it'd been through the apocalypse as it sat outside for god only knows how long. Then I started reading the modification forum and it became a working project. I start work on her when the snow flies, and by spring she's back on the road.

 

I got mine for about four (that's right FOUR) bucks, and that's Canadian! It hasn't run in three years, but isn't missing a thing! Hope to have it running in terrible shape this spring!

 

You could also buy a rack of Keihn Cr carbs(non cv racing carbs) for about 8oo bucks or convert over to round slide carbs for about 500 bucks.

 

at that rate, it would be cheaper to just stick with the original carbs.

FU

 

Original carbs are great as long as they work right. Cleaning them, adjusting them, syncing them, then removing and repeating the process til they work right, is like beating yourself in the head with a hammer.
Round slide and flat slide carbs are so much easier to deal with. When I put my setup on my son-in-laws bike, I cleaned them and put them on, 15 minutes of adjustment and it ran like a top on the first try. Do that with a set of dirty CV's. 500 bucks is well worth it to end the hassle, unless you like hitting yourself in the head with a hammer.

 

depends on the type of hammer?
I read the postings for your bike... have you put up one for the second bike? I'm at the beginning stage of my project, and these carbs seem unnecessarily fussy... I'd be spending a few hundred bux getting them set up... If your method makes things easier, it could be an option.

 

That is true of every carb that has ever been made. I can't begin to tell you how many times I had to take the single barrel Carter carb off of my '64 Cub Cadet before I got it to fuel correctly (and that is a simple slideless carb). The problem isn't the carbs; it's the neglect that they are subjected to before we get the bikes.

 

+1 to that. and after their right they stay right for a long time

 

the carbs I rebuilt for the 550 only need to be taken back off the bike because I forgot to put the heat shield back on after doing the wet set of the floats. when I put them on, it only took a couple cranks and it fired right up. they only required about 20 minutes of tuning and tweaking to get it running like a top. all in it was about $150 for all the rubber parts and gaskets needed to do a complete rebuild.

if you hobgob some other carbs designed for a different engine on your bike, you will have all kinds of fun jetting and tuning them to make it work. good luck with that.

FU

 

I know that switching carbs won't solve my problems... I guess I'm intimidated by the whole process and frustrated at the amount of specialty tools required for basic setup of these machines. Valve retaining tool, float leveler, YICS tool, synch gauge, colortune doohickey, ect. ect. ect... I'm gonna be into this thing for a few hundred bucks before I even get started on the job! But I guess you guys already know that country song!

 

That is the case with most machinery. I'm not a DYI mechanic; I'm a tool collector

Most of what you listed can be made at home for very little money. The valve bucket holding tool for example; use a doubled over zip-ty or a length of unstripped solid copper wire between the open valve and the valve seat.

 

Going through the process with CV's and getting them to work the first time is great. Can't tell you how many times I've seen a post about someone having to go through it 6 or more times. The round slide carbs are so easy to deal with and will handle all the air and exhaust mods you throw at them. After doing the conversion, I was impressed at how simple it was to deal with and how good my bike ran. BTW, didn't have to change any jets with the round slides, just had to adjust the throttle screws and the air/fuel mix screws.
This is a less expensive rout and less work than the EFI coversion. If some of you guys want to keep it stock, that's great too. It's your time and labor.

 

True Dat, K-moe! Has anyone set up threads for the home made tools? How does the zip tie method work? I can't picture it in my mind... How will it hold the valve open?
My plan is to make this bike as simple as possible, and I really don't think I have the skills to fab an intake for a different set of carbs. And I don't even want to THINK about the work I'm facing when I simplify the 80's electronics!

 

The 80's electronics are already simple.

The zip ty (or house wire) method consists of fishing the object through the sparkplug hole and between the open valve and the valve seat so that the valve cannot close.

 

You don't have to do the 2 carb with intakes, you could just do the 4 round slide carb conversion. You would just have to mod the fuel line, petcock, choke/enrichment circuit and find the appropriate throttle.

 

Here is a link from the XJ DIY How-To-Instructions section that provides pictures on the zip tie / wire method.

http://www.xjbikes.com/forums/index...tment-part-2-the-tool-vs-ziptie-w-pics.29209/

There are also some cautions on doing it this way, and IMHO I would recommend purchasing the tool to get the job done.

 

Also, if your bike is a 700 airhead.... You better hope your low compression ISN'T piston rings.....

 

Thanks Rooster! I was thinking that the wire was supposed to be used the same way as the actual tool. How the heck is a wire supposed to push it down? Easy... it isn't! After those concerns about damaging valve seals and disturbing the carbon, I'm kinda leaning towards the tool.
Cost of renting from, and hassle of returning to Chacal, vs cost of buying one... Chances are, I will do this more than once, right?
Like K-Moe sez: "I'm not a DYI mechanic; I'm a tool collector"
As for the "simple" electronics, they're waaaay easier if some PO hadn't already hacked the harness and replaced everything with one color of wire!

 

No doubt, that's a true sign of lameness.......but it's not just PO's that do that. I've got a 25kW Generac generator (4-cylinder turbo Mitsu engine) that has the entire thing....control panel, switches, gauges, engine wiring, etc.....wired with one color (dark blue) wire in the entire thing.....probably a full 1/4 mile of wiring....and that's how the factory did it. Unbelievable.

 

if you put the wires on one at a time and don't screw up, you only need one color, besides that's all i have

 

Your local big box store has them in a variety of colours, every one in the rainbow and then some....

 

No. Thats so you have to pay a tech to come fix it.

 

Tech support? We don't need no stinkin' tech support!

 

easier electronics then the 80's..

yep those are called points and condensers, i've got a 75' Kawi with those..

you should clean and adjust points every 400-800 miles.

and that bike has 3 sets of points.

it's a great machine, just requires very regular "maintainance" every weekend (i ride to work every day i can)

where as the mag pickup's on my xs/xj bikes,
i check them when i get the bike running for the first time, and forget about them.(probibly should re-check them)

but i have yet to have a issue with that part of the system.

PO adjusted wiring.. that's to bad..

my advice, ebay.. just buy another wiring harness, it'll be worth the 30-40 bucks (that's what my last seca harness cost)

and they are not to hard to swap, just be care full, take your time, and keep in mind that the relay down by the brain box has the same type of connecter as one for the brain box, mix those 2 up and you will fry the brain box. ...

just do 1 connecter at a time and you'll be fine.

good luck!