How to Change the Spark Plugs on a 2001-2003 Honda CBR600 F4i

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Table of Contents

Introduction & Precautions…………………………………………………………3

Parts and Tools……………………………………………………………………..4

Section 1 - Disassembling the Motorcycle…………………..……………..………5

Section 2 - Installation of New Spark Plugs……………………………………....10

Section 3 - Reassembling the Motorcycle…………………………………..…….12

References………………………………………………………………………...13

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Introduction

Like anything else, the components inside any machine will wear out over time due to use and/or misuse. Your vehicle is one of the single most important machines you possess, therefore it is also one of the most important to continually maintain. One of the best ways to save money with any vehicle is to keep it properly maintained. “Missing even one oil change can accelerate premature engine wear and cause engine damage, reducing long term car reliability” (Consumer Reports).

There are many different components of a vehicle, in our case, a motorcycle that will need to be replaced over time. Every mile you ride will cause wear on practically every component of you motorcycle. Luckily for you, Honda is renowned for dependability. This means you probably won’t have to replace major engine components very often, a probability that can be further insured by proper maintenance. In addition to keeping the larger components of your motorcycle safe, like your engine, new spark plugs can improve your fuel economy and performance: “Misfiring spark plugs can reduce fuel efficiency as much as 30%” (Hirsch).

This manual will cover how to disassemble your bike for easy access to your spark plugs, how to actually change your spark plugs, and how to reassemble your bike. If followed correctly you should be riding around enjoying your improved performance and fuel efficiency in about an hour and a half.

Disclaimer: This manual assumes the reader is familiar with motorcycle and tool nomenclature as well as the Honda CBR600 F4i motorcycle itself.

Precautions

WARNING: Performing any kind of modifications to any vehicle may void manufacturer’s warranty. Check your owner’s manual or call your local Honda dealership if concerned.

CAUTION: This manual involves some risk to your vehicle and yourself in the methods used, as does most work on any vehicle. Be sure to follow the manual accurately and precisely to minimize as much possibility of injury to yourself or damage to your vehicle as possible.

CAUTION: Do not attempt to follow is manual under the influence of any drugs or alcohol. Serious injury could result due to carelessness.

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Parts and Tools

4 x New spark plugs 4mm, 5mm, and 6mm Allen Head Wrenches 8mm Socket Head and Straight Socket Driver 2 x #2 Phillips Head Driver (one with a blunt end, one with a sharp end); Note: If you

can, acquire a driver set like the one shown below where you can use multiple different ends on the same driver. The set shown also has Allen head ends (which was used for the 4mm Allen bolt driver).

Socket Joint Attachment; Note: This tool may be the single most important for this job of all the tools listed.

3/8”->5/8” Spark Plug Socket; This tool should have a rubberized interior to protect the spark plug during installation.

3/8” Socket Extension 3” Long 3/8” Ratchet Wrench Small plastic container to hold bolts and screws (suggested) Motorcycle Jack/Stand (suggested)

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Shown here are the required tools for removal of fairings and installation of spark plugs.

Section 1 – Disassembling the Motorcycle

This section will explain how to gain access to the spark plugs. Luckily, there are few items that need to be removed, however the process does take some time and can prove to be rather frustrating if the correct methods or tools are not used. Give yourself about thirty minutes for this section to allow for careful removal to ensure nothing is damaged during the process. If you possess the option, you should ensure stability during the process by using a motorcycle jack/stand. Whenever you remove an item from the motorcycle store it in a safe location out of your way, to protect it from damage, until you reassemble the bike. Also, as you remove bolts and/or screws place them in a plastic container so you do not lose any of them.

1. Remove the driver’s seat by unscrewing the two bolts under the two back corners, as shown in Figure 1-A, using a 5mm Allen bolt driver.

2. Remove the small upper front fairing by removing the bolt using a 4mm Allen head driver and the screw using the sharp #2 Phillips driver. See Figure 1-B.

3. Repeat step 3 for the opposite side.4. Remove the two bolts on both sides of the tail fairing near the passenger seat using a

6mm Allen head wrench and the two bolts on both sides near the driver’s seat using a 4mm Allen head wrench. See Figure 1-C.

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Figure 1-A

Figure 1-B

5. Remove the tail fairing by carefully sliding it towards the back of the motorcycle as you guide it up and over the bar that had the two 6mm Allen head bolts in it. Once you reach the point where it can no longer go back due to the narrowing of the design, pull the right side over the bar after taking the two relays on the right side near the bar off of their bracket by simply pulling them up, this will give you more room to maneuver. Then pull the left side over in a similar manner while being careful not to damage the faring on the metal box that is under the bar.

CAUTION: This step is very difficult due to the lack of space in which to maneuver the tail fairing. Be very careful not to place too much stress on the fairing when freeing either side or there is a good chance the tail fairing will crack. Use the method described to avoid the possibility of damage.

Note: This step is not completely necessary; however it is strongly suggested to ensure there is no damage to the tail fairing, the paint of the tail fairing, or the gas tank during the rest of the process.

6. Remove the two bolts at the back of the gas tank using the 6mm Allen head driver. See Figure 1-D.

7. Remove the two bolts at the front of the gas tank using the 8mm socket and straight socket driver. Figure 1-F.

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Figure 1-C

Figure 1-D

Figure 1-F

8. Suspend the gas tank in the air so you have at least enough clearance to fit a Philips head driver between the tank and the air box. There are a few different methods in which you can accomplish this; the simplest and easiest method is using a piece of 2x4 between the front of the tank and the part of the frame that it was bolted onto. See Figure 1-G.

CAUTION: Be very careful not to knock into the 2x4 as you proceed or the gas tank will fall and could injure you. Also, make sure you do not accidentally pull any of the fuel lines off of the gas tank by not propping it up too far or you could incur a fuel leak.

Note: You can also completely remove the gas tank to avoid this risk; however gas tank removal will not be covered in this manual for the sake of time and ease. Gas tank removal also involves emptying the tank of gas and could cause more safety risks if done incorrectly.

9. Remove the three screws holding the leather dust cover onto the side of the air box, as well as the one near the center of the front, the one at the center of the back, and the one in the very middle of the air box using the sharp #2 Phillips head driver, and disconnect the wiring harness from the air box. See Figure 1-H.

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Figure 1-G

Figure 1-H

10. Remove the remaining three screws from the opposite side holding the other dust cover on as well as the one remaining screw near the front of the air box using a sharp #2 Phillips head driver.

11. Remove the top half of the air box along with the now exposed air filter.12. Remove the six screws on the back side of the air box securing the throttle body Velocity

Stacks using the blunt #2 Phillips head driver. If you have trouble finding the screws, look for the small sections cut out of the top of the round Velocity Stacks. See Figure 1-I.

13. Disconnect the five vacuum hoses connected to the base of the air box: one large and two small hoses in the back; one large hose in the front; and one more small hose connected to the base of the map sensor (on the bottom left front of the air box). Also, disconnect the map sensor from the wiring harness.

14. Loosen the bottom half of the air box by picking it up from the back side and sliding the ram air ducts so they separate in the middle. Once the air box is loose, remove it by orienting the air ducts up so your 2x4 is between the two ducts, then turn the air box to the side and remove it without hitting the 2x4. Your engine will now be exposed as shown in Figure 1-J. You may want to put a cover over the throttle bodies to ensure no debris gets into to combustion chamber.

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Figure 1-I

Figure 1-J

Section 2 – Installing the New Spark Plugs

This section will explain how to remove your old spark plugs and install your new spark plugs and will take approximately 20 minutes. I chose NGK IMR9A-9H spark plugs for my motorcycle. This was actually a mistake due to NGK’s website listing the wrong spark plug for the 2001-2003 CBR600 F4i. The correct plug from NGK is the IMR9C-9H, however if you mistakenly got the IMR9A-9H do not despair, the differences are negligible. The only difference is a tapering of the electrode end of the plugs and will only cause a very slight performance difference if any. Also, there are many different spark plug manufacturers, so NGK is not required. If you ever have a doubt about which plug to use there should be a small chart on the plastic piece under the passenger seat on the right side which will display the manufacturer’s recommendation. Also, you can always visit your local auto parts store, call your local Honda dealership, or do a quick search on the internet for compatible plugs from different manufacturers.

1. Disconnect the spark plug boot from the wiring harness of the spark plug you would like remove first. See Figure 2-A. For simplicity you should start with a spark plug on either end, however not one of the two in the middle. Also, do one spark plug at a time so not to confuse the wiring harness connectors or spark plug boots with their corresponding location.

2. Remove the spark plug boot corresponding to the electrical connector that you disconnected. The boot may require some playing with to get loose since they are required to be set in air tight. If you cannot get it loose by hand a set of pliers may be useful for assistance, however be careful not to damage the boot by applying too much pressure when squeezing the boot with the pliers.

3. Assemble your spark plug tool by using your 3” long 3/8” socket extension attached to the female end of the 3/8” socket joint with the 3/8”->5/8” spark plug socket on the other end of the socket joint as shown in Figure 2-B.

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Figure 2-A

4. Holding the extension in your hand, angle the spark plug socket into the engine without your ratchet wrench attached yet for the sake of space. You should be able to get the spark plug tool onto the spark plug with just enough of the extension sticking out of the engine to connect the ratchet wrench on the end of the extension. See Figure 2-C.Note: Without the socket joint fitting a socket extension into the engine and removing with the spark plug on the end would be nearly impossible due to space constraints.

5. Connect your ratchet wrench onto the end of the socket extension and remove the old spark plug. Repeat step 4 in reverse to take the spark plug tool out of the engine, which now has the old spark plug on the end of it. See Figure 2-D.Note: This is a good opportunity to inspect the spark plug to see how it has been performing. There is a plethora of information online to determine what the condition of your old spark plug indicates.

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Figure 2-B

Figure 2-C

6. Set the new spark plug in the spark plug socket in the same manner as the spark plug you removed. Reference Figure 2-D.

7. Install the new spark plug using the reverse of the method you used to remove the old spark plug, however once you have the spark plug tool inside the engine with the new spark plug on the end tighten the spark plug first by hand. Once the spark plug is hand tight connect the ratchet wrench onto the end of the spark plug tool and tighten it one more half of a rotation.

CAUTION: Over tightening the spark plug can cause damage to the aluminum threads and will cause major issues with the engine. Be very careful not to over tighten by using the method described.

CAUTION: Be careful not to hit the end of the spark plug against anything during installation. Doing so could change the gap and will affect the performance of the spark plug. If the gap is effected it must be properly regapped.

8. Replace the spark plug boot ensuring that you hear two to three light pops letting you know it has been properly set as the rubber gaskets create an air tight seal. You should not be able to see the rubber gaskets at the top of boot if it has been properly set in the engine.

9. Repeat steps 1-8 for the other three spark plugs.

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Figure 2-D

Shown above is a comparison of four old spark plugs (right) and one new spark plug (left).

Section 3 – Reassembling the Motorcycle

Refer to Section 1 for reassembly, and perform the process in reverse. Like Section 1 this section will also require at least thirty minutes. Be sure to tighten all of the bolts and screws very snug, but not too tight to damage any of the components of the bike. Remember a bike experiences a lot of vibration as well, so if the bolt or screws aren’t tight enough they may work themselves out and fall off while you’re going down the road. Be sure to connect all hoses and wiring harness connectors or your motorcycle will not operate correctly. If after reassembling your bike it is not running correctly, go back through Section 1 to double check if anything was not replaced back to the condition it was in prior to disassembly. Even one vacuum hose disconnected will make the motorcycle malfunction; especially the small hose connected to the bottom of the map sensor (see Step 13, Section 1).

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References

Consumer Reports. Go by the book. October 2009. 21 September 2011 <http://www.consumerreports.org/cro/cars/tires-auto-parts/tires/making-your-car-last-10-07/go-by-the-book/200k-book.htm>.

Hirsch, Jerry. Tips to improve your vehicle's fuel economy. 10 March 2011. 21 September 2011 <http://articles.latimes.com/2011/mar/10/business/la-fi-autos-fuel-20110310>.

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