Z1300 and KZ1300 Fuel Injection Conversion

		Z1300 DFI Conversion

Last Update 8/22/08

This page shows a Kawasaki KZ1300 carbureted bike being converted to fuel injection using the later model ZN1300 Voyager throttle bodies and DFI computer. I started this mod because I have the need to test run engines quite frequently that come through my shop since I work on so many of these bikes. I'll get a bike that's been sitting for years and I try to bring the engine back to life. Usually the compression is real low so there's not much suction through the carbs. Even if I have what I know to be a good set of carbs it's still hard to get the motor started when you don't have good compression. Since the DFI meters fuel based on RPM, it injects the right amount whether you have compression or not.

If you're considering converting your bike to DFI, please note that you cannot use solid core spark plug wires with a fuel injection computer mounted on your bike. Here is an excellent article on the Magnecor website called "THE TRUTH ABOUT IGNITION WIRE CONDUCTORS" relative to electromagnetic interference caused from using solid core wires. Damage to your computer could result from using the wrong wires!

Usually the first thing you have to do on one these old motors is check the valve adjustment. I don't know why so many guys buy these bikes and ride them and never get around to adjusting the valves, but I've never bought one of these bikes and found that the valves were in proper adjustment. I guess the fact that our intake valves wear 'tight' and don't make ticking noises when they need adjustment, keeps some people from thinking that an adjustment is necessary. As our valves wear the clearances get smaller, or we say 'tight' because the valve can get to a point where there's no clearance and it doesn't close completely. At that point you eventually start losing compression in that cylinder and you lose overall performance, but it's a gradual thing so most don't notice until it's actually pretty bad. If you continue to ride it like that you'll eventually burn a valve because it's being held open all the time. This is usually the point where I get the bike because it's been sitting in someone's garage for years and either they couldn't get it started or it needs work and they don't want to put money into it.

So I get one and the first thing I do is check compression. A brand new motor should be approximately 155 - 160 lbs, but I see 90 - 110 lb readings all the time on these bikes I buy. Still I want a baseline reading on each cylinder before and after valve adjustment so I can see how much good it did. Other things I generally do on an old motor like this is to spray some penetrating oil in the cylinders when the spark plugs are out. You never know how much surface rust might be down in your cylinders and you don't want to spin the motor without some lubrication in the cylinders.

As you can see in the pictures I have a modified stock cam chain tensioner mounted on this engine. DO THIS FIRST, before you spin the motor the first time! Never turn the motor with the original stock tensioner in it because this is usually when the tensioner will fail. Especially when a motor has been sitting a long time this tensioner doesn't have fresh oil residue on it and even if it does, it's just a bad idea to run these motors with the original tensioners. We cover this subject in great detail on this site, but I just worked on a bike that this very thing happened to. A guy locally bought a 1300 with 8000 original miles and when they tried to start it after sitting for a couple of years it jumped 2 teeth on the exhaust cam. They knew the engine was running good when it was sat up so no one expected that it had jumped time.

Another mechanic had looked at it and he couldn't figure it out, but he discounted the idea that the cam timing could be a problem as it was trying to start, it still had about 120 lbs of compression and it was running good before it was sat up. Good thing it didn't fire off because if it had of started up more than likely it would of bent the exhaust valves after it started. As it was, I re-timed the cams, adjusted the valves and it fired right up and ran perfectly. The valves were probably just barely making contact with the pistons but no harm seems to of been done. Had the motor had been running when it jumped, bent valves are a more likely scenario. When a mechanic says he never heard of a cam chain tensioner problem on these bikes and doesn't think it's necessary to replace it, ask him if he'll replace your bent valves for free if the CCT goes bad. YOU'VE HEARD OF cam chain tensioner problems on these bikes because you've heard about it here. I've seen it, Paul's seen it, other members have experienced it and it's a simple fix, so it's just not worth risking an expensive valve job versus the cost of preventing the problem.

In theses next 3 pictures I want to make everyone aware of one potentially dangerous problem relative to fuel injection on our 1300's. Our bikes whether carb or fuel injected use a 5/16 fuel line. However, BE AWARE that the ZN1300 uses a pressurized fuel system that operates around 33 - 36 psi or more. Below you'll see 2 types of 5/16 fuel hose. One states 'Fuel Injection Hose' and the other says 'Not For Fuel Injection Systems'. The one that say says 'Not For Fuel Injection Systems' is regular fuel line for cars or motorcycles that typically have fuel pumps on them, but they have carburetors and usually don't operate with more than 3 - 5 psi of pressure. I realize that carburetors on race cars may operate on pressures up to 30 lbs, maybe more, I don't know what the current state of the art is.

Our carbureted KZ bikes didn't come with fuel pumps as they're just gravity feed, but some times members have installed low pressure fuel pumps on their Z1300 to solve fuel delivery problems and that's OK if that works for you. Still we're talking pumps with an output of about 3 - 5 psi of pressure on a bike with carbs. On the 1300 Voyager we're talking about fuel pressures around 33 - 36 psi or more if you use an adjustable regulator. Here's the problem... you can't use the 5/16 fuel hose labeled 'Not For Fuel Injection Systems' on the pressure side of your fuel system on the Voyager 1300. You can use it on the suction side from the gas tank to the fuel pump and you can use it on the return line AFTER the fuel pressure regulator, as the return line from the regulator back to the tank will be substantially less pressure. I am using regular 5/16 low pressure fuel line for the return line hose on these 2 bikes with no problem, but the point is that if you're using 5/16 hose labeled 'Not For Fuel Injection Systems' on the pressure side of your fuel system you're asking for big trouble.

Like maybe a fire between your legs! How would you like to spring a gas leak at 35psi and have gas spraying all over you while you're shooting down the freeway at 70 mph!!! Boy you haven't lived until you've done that! You can buy this high pressure hose at your local auto parts and your bike shop may have it too, but keep in mind your bike shop probably doesn't work on many old fuel injection systems as the ones they do get are probably fairly new bikes and don't need new fuel hoses. If they actually needed some hose like this, they'd probably send someone down to the auto parts to get it. Be ready to pay $6 a foot for it or more because it's not near as cheap as the low pressure hose.

I don't know what exactly what pressure the 'Fuel Injection Hose' is rated at, but I can tell you that the standard 'Not For Fuel Injection Systems' hose seems to be able to handle 33 - 36psi for a period of time because I've had 2 Voyagers in my shop with the 'Not For Fuel Injection Systems' hose on them and they hadn't blown up yet. But I did notice that the hoses on one were badly cracked and I bet it could of blown at any time, so don't take the chance. Look at your bike and if it doesn't say 'Fuel Injection Hose' on at least the pieces on the pressure side of the system that goes from the fuel pump to the fuel rail on the right side and from the fuel rail down to the pressure regulator on the left side, don't ride your bike till you've dealt with this. I guess it goes without saying if you still have the original hose on there from 1984... Just be sure you've got good high pressure hose on your bike.

In these next images you can see how I modify the hose from the fuel filter to the fuel pump inlet when using a ZN1300 fuel pump on my test bench system. Right now on the stock setup you have a 5/16" outlet on your filter that goes to a 1/2" inlet on your pump. I buy some brass fittings and basically make an adapter with a 5/16" inlet and 1/2" outlet. Then I can run 5/16 hose down to the pump and don't have to have the special stock Voyager 1300 adapter hose from Kawasaki to make it work. This straight through setup I'm using on my test bench. On a bike I use a 90 degree fitting because it's very tight quarters in that area. Another option when working on a ZN1300 is simply to turn the pump around with the inlet on the left outlet on the right. This gives you more room to run your new lines if you're just replacing hoses.

Then you can hook up any style straight through filter you might find from the auto parts store that fits in the space. Take your outlet down to the left side and there's more room to work with over there for your adapter. The pressure outlet on the right side can be turned so it's pointing straight up and that's an easy run up to the fuel rail right above. I've found there's enough slack in the fuel pump wiring to reach if you're careful how you fit the wires in place.

In these images you see what the throttle bodies look like with new injectors installed.

In these images you can see how it fits up to a KZ1300. These are my test bikes, I did a 79' KZ1300 first and then the 80' B2 model. Now I'm running motors off my engine stand using this setup.

On the right side you can see how the stock ZN1300 fuel rail interferes with the KZ frame on the fuel rail inlet. After you modify the inlet position, which has to be done because otherwise it's under a lot of pressure up against the frame, the fuel rail will just clear the frame rails on both sides without touching.

There's a few things you see from looking at the pictures. My coil set has extra long wires on it and the 3 coils are tie-wrapped together and held to the frame with Velcro tie-wraps. I made short interchangeable adapters where I connect the ground side of the coil because the KZ's use round connectors and the ZN's use spade connectors. This way, if I have a bike in and I suspect bad coils I can connect my test coils up and if it's a ZN I just use my adaptors and plug the coils into the original wiring harness. With the extended igniter connection wires, the separate power wire and the long spark plug wires, I can tie-wrap this whole assembly down by the right side-cover, make the connections and take the bike for a ride. If that solved the problem then I know to put new coils on the bike, but at least I've been able to test ride it without even pulling the old coils off!

You'll notice I have an extra fuel injector plumbed in on the left side fuel return but before the pressure regulator so it gets pressurized fuel. You also see I moved the fuel pressure regulator out from where I had it originally and added a fuel pressure gauge. I've since bought an adjustable fuel pressure regulator that has a connection right on the side of the regulator where I've mounted a liquid filled fuel pressure gauge. I'm installing this setup on my ZN1300 so I can experiment with the effects of raising the fuel pressure. If you read the FAQ page you'll see this thought discussed there. I used this gauge and extra fuel injector on my test rig for diagnostic purposes when I was trying to get this system up and running.

I found a clear bottle that fit perfectly over the end of the injector, then I pulled the connection off the #1 injector and connected it to my 'diagnostic' injector so when I cranked the motor I could visually see that gas was being metered into the motor. For the fuel return line I just ran it back in the gas tank at the cap. I used the fuel pressure gauge to monitor my fuel pressure. The whole issue is that it's very difficult to hold the throttle body wide open and look up inside with a light and see if fuel is actually coming off the injectors. This setup I did just made everything a no-brainer because all the injectors fire at the same time, so once you can see the diagnostic injector working, you know they're all working.

The wiring is not difficult at all as there are two 12 volt positive '+' wires that go to the DFI computer and a ground wire. I'll post a simplified wiring diagram when I get something drawn up but basically for these test purposes you have your power wires to the DFI and a power wire to the igniter, fuel pump, coil pack and a power wire to the starter solenoid which you run through a momentary switch just like the starter button on your handle bars. I use a master on/off switch and you've got ground wires from the battery that connect back to everything. On the DFI harness you've got the 3 'RPM or speed sensor' wires which you splice to the ground side of your coils; 2 wires feed your injectors and those 2 are all spiced together as 6 positive and 6 negative; 2 wires go to the air temp sensor; there's a group of wires that all go to the throttle position sensor and there's a single wire for the water temp sensor. It's a little easier if you're just doing a DFI conversion because your igniter and coils are already in place and powered up by the ignition switch. Here, I'm powering everything separately so I can bypass the wiring harness on the bike for diagnostic purposes.

Your stock igniter wires are separate from the DFI system even on the ZN1300, so your ignition advance is in the igniter or it's a mechanical advance on the 79' and 80'. No doubt if you hook this up you'll fall in love with it and if we get the MegaSquirt DFI system going some day or adapt some other DFI controller it will be even better since the Voyager parts are so expensive to use to make a conversion like this. But I think you'll find this will make your bike run smoother, have better throttle response and I estimate it should get at least 10 mpg better gas mileage to boot. I say that because a fuel injected Voyager gets 10 mpg better mileage than a KZ1300 with carbs and the Voyager is carrying about 200 lbs more weight around with the addition of the full fairing and saddlebags.

The next 4 images are of a 'Muse Motorsports' adjustable fuel pressure regulator I'm testing. I want to see what the maximum fuel pressure is that our stock pumps are capable of. After testing a couple of pumps I'd say 60 lbs seems to be the maximum these stock pumps were capable of delivering. When I get this installed on my Voyager I'll test to see if there's any mileage difference between running the stock pressure and 10lbs over, 15lbs over, etc. One thing I noticed is you don't get any fuel return out the fuel return line over about 50 lbs, so I'm going to stay below 50 lbs. Maximum observed fuel pressure on a stock pump was about 60 psi, with the pump powered on, but before I started the engine.

The theory is, if we raise the pressure about 10 lbs it will compensate for the changes in fuel formulations over the last 20 years and make our bikes run better. The speculation is that our bikes are running too lean because of the reformulations made in the fuel in that time period. When I get this installed and tested I'll post more pictures but you can buy these adjustable fuel pressure regulators pretty cheap off ebay. I paid $38 for this one with the gauge, and you want one like this that has the gauge right on it so you can glance at it to confirm your pump is working properly if need be. Alternatively you could run a steel braided fuel line from the pressure regulator up to your front fairing somewhere and mount the gauge in a spot where it's easier to see. Keep in mind this has to be a hose that won't wear through or get damaged and leak, so that's why I suggest a steel braided line if you go this route.

This came with a mounting bracket and it's very easy to adjust by loosening the nut on the top and turning the set screw to adjust pressure. I also bought a liquid filled gauge that reads 0 - 60 psi to replace the gauge 0 - 140 psi gauge it came with. One thing to be careful of when you buy these regulators is that some of the cheap ones including the one you see here didn't use pipe threads on the inlet and outlet hose fittings. I wanted to change these to 90 degree fittings instead of the straight ones that came on it and I couldn't screw the 90's in place because the thread on the original fittings is just a standard screw type thread, not a pipe thread as you would expect. Any fittings like this you would buy here in the USA will be pipe thread, so I had to buy a 1/4" SAE pipe thread tap and disassemble the regulator and tap new threads over the old ones. Didn't seem to be a problem since you're cutting a deeper or wider thread anyway, but you have to pull it apart to make sure you don't get any metal chips inside the regulator and ultimately into your fuel line.

As of 12/15/06 I've done an actual DFI conversion with this setup on an 81' KZ1300 A3 I bought out of Kentucky. Go here to read about that install -

http://www.kz1300.com/81-kz1300-kentucky.html

Here's a Windows Media .wmv file with a short 40 second video clip of the first motor I did as it's running at idle. This clip is a little over 7 megs in size so don't try to download it unless you have a fast internet connection. Secondly, opening this file in your browser may hang some computers depending on how your browser is configured to handle a .wmv file. It may be better to use the option to save the file to your computer's hard-drive first, then open it. You might need to right click on the link to access a "save" or "save as" feature on your browser so you can save it to your PC.

kz1300.com/techarticles/kz1300-dfi-test-rig1.wmv

Turn up the Bass, crank up the volume and stay tuned for updates! david@kz1300.com

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