How to clean or replace fuel injectors

All,

I created this document after figuring out how to do this after many hours of frustration and research, and finding very little, but enough information so that I proceed with enough confidence. Hopefully this helps others and thought I would give back to the community that has helped me. My symptoms were the bike ran on 2 of 4 cylinders after sitting for a week. I previously filled up gas about 25 miles previously. When I started the bike, it was half of what it should have been. I add fuel additive to clean out the fuel system, and rode it for 30 miles and no improvements. It was either a fuel or electrical issue. The fuel side would be easier and cheaper to troubleshoot, and I would be able to check the spark on the plugs while the bike was disassembled. In the end, what I have detailed below did fix the issue, cost me about $60 in a few extra specialty tools, parts, and chemicals. I was able to also replace my plugs. The best part is that I learned about how fuel injection works after being used to rebuilding carbs, and I saved over $500. So knowledge, having fun, and saving money equals win!

I have had fellow riders and non technical people help to proof read it, though I am sure that it is not perfect. Feel free to make corrections. I did not try to use correct nomenclature. I used terms that most people would understand. I have the document in Word form with pictures and arrows so you can print it out. I tried to upload it, but it is too large. Feel free to contact me at my user name at Gmail.

Hope it helps and best of luck!


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How to clean or replace fuel injectors
This document is designed to help others who want to attempt to do this at their own risk. I did not try to have the correct nomenclature for parts, but instead have used basic descriptions for parts. These are my notes I have made for myself for my bike (2007 Yamaha FZ1) , and have modified them so others might find it useful. Use this at your own risk!
Read these instructions ahead of time before you start so that you can make a list of things you will need without stopping and running to the store for a tool, part, or chemical.
This took 4 hours my of my time, and has gone to a little less than an hour now that I know the process.
CAUTION: Use eye protection and other shop safety equipment before you start. You will be using chemicals and tools that could end your days of riding permanently. I have been blinded for 24 hours in the past by not paying attention. Do all work in a well-ventilated area due to explosive fumes and clean floor in case you drop parts.
1. Take notes or pictures. Pictures are preferred as you disassemble the bike, and keep parts that you remove in a safe area away from feet. I keep parts and screws in sections for easier assembly, especially if there is a week or two in between pulling it apart and putting it back together.
2. Remove side fairings by unscrewing the 2 Phillips head screws on each fairing, and then the 2 side Allen head screws.
3. Remove upper tank fairing using an Allen head wrench. There are 4 smaller Allen screws, and one large one in the center of the upper fairing.
4. Remove the two side Allen head screws from the front of the tank, and then loosen the one from the rear of the tank, but keep it in place for step 5.
5. Lift the fuel tank and then by pushing back the connection lock and then pushing in the 2 connection buttons holding fitting onto fuel tank pipe. It helps to push in and twist left and right while pulling down. There will be some fuel leakage, but not much.
6. Remove the fuel vent overflow hose by removing the retaining clip and then feeding the hose through the retention grommet.
7. Remove the 2 wiring connections by pushing in the disconnect button. DO NOT try to force the connection out. If you disengage the holder correctly, the connectors come out very easily.
8. Remove air box sensor connector, air box Philips screws, air box cover, and then remove the air stacks that are inside of the air box. Each of the stacks has 3 Allen head screws.

9. Remove the aft air box rubber hose and hose under the left side of the air box.
10. Disconnect fuel line from fuel supply pipe into injectors by pushing back the connection lock and then pushing in the 2 connection buttons. It helps to push in and twist left and right while pulling down. This is a bit difficult, but DO NOT force, just be firm and keep twisting.
11. Disconnect the connection pin on top of the fuel supply pipe
12. Remove the 2 screws from the supply pipe. If they do not twist out easily, STOP! DO NOT strip them! You can use an impact driver to remove them. This is under $20 at Sears as of 7/25/14, and will save many hours of time, sweat, and frustration.
13. Once the screws are out. STOP! DO NOT pull out the fuel supply pipe from the fuel injectors. There are O-rings inside of the pipe to keep the fuel system pressurized and to not leak fuel when power is applied to the fuel pump.
14. From either left or right side of fuel pump, hold injector in place, and slowly rock the fuel supply pipe forward and back to very carefully disengage injector, paying attention to the top of the injector and not losing the O-ring inside of the injector pipe. If they are broken, then I will cover this later.
15. Continue to work down to the 2nd, 3rd, and then 4th injectors, keeping injectors seated until fuel supply pipe is completely removed.
16. Pull out each injector, slowly! There is a rubber seal that fits inside of the intake manifold that may stay in the manifold, which is preferred, or stays on the injector. If it stays on the injector, place it back in the manifold, being very careful to not drop it. I used needle nose pliers to put it back, and holding my finger on it once in place to seat it in the manifold.

17. Disconnect the wire to the injector by pressing the release button on the underside of the injector and wiggling the wiring back and forth until it comes out. The wires are only long enough to go to the specific intake, so I didn’t need to number them.
18. Now that all of the injectors are out, you can use intake cleaning spray into the top of the intake and where the injectors were. Wear eye protection and spray liberally. There is a lot of back spray, so watch your eyes!
19. STOP! Proceed with caution as injectors are about $150 each to replace.
20. A bit of explanation to help with understanding the fuel system for those who do not know. The injector system works by the fuel pump that is located in the fuel tank. It pressurizes the fuel supply pipe that supplies the injectors, which have a valve that opens and closes, and fuel is supplied into the cylinders through very small holes in the end of the injectors. The only way to remove debris from the injectors is to reverse the flow and gently push cleaner and air through the injector back out the way it came.
21. To clean the injectors, you will need a clear 5/8ths (?) rubber pipe, a syringe or turkey baster, a NEW 9 volt battery, and wires to connect the 9V to the injector connectors.
22. I used a 9V battery connector with leads, and the Micro Scale Test Lead Kit from Radio Shack. I think I spent $25 total on both, and made the job SUPER easy!
23. Connect 9V battery set up together, and connect rubber hose to the end of the injector that sprays fuel into cylinders.

24. Connect 9V test set to injector. As soon as you connect it, you will hear a click, which means your injector IS working. If you do not hear a click, make sure your 9V is fresh.
25. Connect tubing to spray end of injector making sure to have a good seal so cleaning fluid does not leak out of rubber hose.
26. Spray cleaner down in tube, and use syringe or turkey baster to gently push fluid through injector. DO NOT use compressed air as that could blow your injector. If a $5 tool is not worth a $200 injector times 4, then the best of luck to you!
27. You should see fluid coming out of the end of injector freely.
28. Once the injectors are clean and free of debris, then let them air dry.
29. One thing to consider is replacing the spark plugs while everything is apart. This is not very hard to do, just remove the two screws supporting the radiator, and using a 3” extension and a 5/8 spark plug socket, you can remove and replace each plug in about an hour or less, and save you some $$$.
30. If the O-rings were broken or damaged, you can order them from your local shop, or you can get some O-rings from the plumbing section of your favorite hardware store. I got the #6 and #7 O-rings for $6 at Lowe’s and used 1 of each on 3 injectors, and the #6 in the last injector due to fuel leaks.

31. Place the connector back into the injector, and push it firmly back into the manifold. Do this for each of them.
32. Place a bit of liquid lubricant on fingers and get O-ring on top of injector slightly lubed. I used WD40.
33. Start from either the left or right injector, place the injector supply line into the first injector, and continue to work until all injectors are sitting in the supply line.
34. Press down slowly, and firmly to seat the injectors into the supply line, and then replace the screws and tighten them.
35. Plug in connector into the injector supply line.
36. Place supply gas line into injector supply line.
37. Connect gas supply line to gas tank, and plug in wires into the fuel pump.
38. Turn the key in the ignition to pressurize system and make sure there are no leaks in fuel system.
39. Once there are no leaks, remove tank, zip tie all loose wires. Reassemble everything opposite the way it was taken apart.
 

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Decent write up on how to for those who dont know.

My question is how did the debris get into the injectors in the first place?
Bad gas can definitely cause fueling issues but usually a drain and replace with fresh will solve the issue.
Is the fuel filter not in tact? full of crap? I'd replace that too or ya may be doing all that again.
 
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