Post image for How to Change the Spark Plugs in Your SV650

An engine won’t get very far without spark, a courtesy that the spark plug provides. The maintenance chart for the SV650 recommends replacing the spark plugs every 7500 miles, and here’s a step-by-step guide how to do it.

Like all of my how-to guides, this one is written for those who are new to wrenching. As such, it’s written at an exhaustive level of detail. If you’re experienced at performing your own maintenance, click here to skip right to the summary.

In this guide, we will change the spark plugs on a 2007 SV650. These instructions apply for all dual-spark models of SV650, i.e. from the 2007 model year onwards. If you own a faired (S or SF) model, you may need to remove some plastic. You’ll have to consult your owner’s manual for instructions on removing your fairings.

“Dual spark” refers to having two spark plugs per engine cylinder. The SV650 has a V-twin engine with 2 cylinders; thus, a dual-spark SV650 will use 4 spark plugs.

Step 1: Gather the Required Tools and Materials

Tools:

  • 5/8in spark plug socket
  • ratchet wrench
  • 3in and 6in extensions
  • 10mm wrench
  • spark plug gap tool
  • hex (allen) bits or wrenches: 4mm and 6mm
  • bit driver

Consumables:

  • 4 spark plugs (NGK or DENSO)
  • anti-seize compound

Optional:

  • torque wrench
  • 2×4 block of wood

A Note Regarding Spark Plugs

Iridium. Dual electrode. You can spend a lot of money on fancy spark plugs. If you’ve got the cash and it makes you feel better, knock yourself out. Me? I use regular NGK plugs and follow the heat ranges in the service manual.

Standard Cold Type Hot Type
NGK CR8E CR9E CR7E
ND U24ESR-N U27ESR-N U22ESR-N

I could spend all day writing about spark plugs and heat ranges and all that jazz, but all you really have to know is that for regular street riding on a typical SV, go with the standard heat range. If you’d like to read more about spark plugs, NGK has a very nice guide: Tech Info – Spark Plugs Overview

A Note Regarding Spark Plug Gap Tools

Don’t bother with anything other than a wire or blade type gap tool.

A wire-type gap tool.

A wire-type gap tool.

If you’re trying to gap your plugs with one of those 50 cent “coin” style tools you found at the checkout counter, bin it and get a better one. I think this one cost me 4 or 5 bucks at Napa. Trust me on this.

Step 2: Move the Radiator

This maintenance should only be performed on a cool or cold engine! A hot radiator or engine cylinder can burn you.

First, locate the plastic “fender” attached to the bottom-most fork clamp. Here’s a picture of it from the service manual (marked with “1″):

sv650 radiator fender

Use a 10mm wrench to remove the bolt circled in the picture. Then, remove the fender piece and set it aside.

Next, locate the radiator mounting bolt on the right side of the bike. (For the purposes of this guide, the right side refers to the side that’s on the right when you’re seated on the bike.)

Remove the radiator mounting bolt using the 10mm wrench.

Remove the radiator mounting bolt using the 10mm wrench.

Use the 10mm wrench to remove the bolt. Once the bolt is gone, gently pull the radiator assembly toward the front wheel. This will give you some room to work on the plugs in the front cylinder. If you have a block of wood, you can use it to hold the radiator out of the way.

Step 3: Replace Front Spark Plugs

Now, locate the two spark plugs in the front cylinder. Plug “A” is on the right side of the front cylinder and plug “B” is tucked into the front-most part of the cylinder.

Front plugs 'A' and 'B'

Front plugs 'A' and 'B'

Start with plug A, as it’s by far the easiest to remove. Remove the rubber boot covering the spark plug by grasping the plastic cap and pulling it straight out.

Front plug A with rubber boot removed.

Front plug A with rubber boot removed.

Then, use the 5/8 inch spark plug socket and ratchet wrench to loosen the plug.

Loosening front plug A with spark plug socket and ratchet wrench.

Loosening front plug A with spark plug socket and ratchet wrench.

Once the plug starts spinning freely, you can use your fingers to loosen it the rest of the way.

Success!

Success!

New spark plugs should be “gapped” before being installed. The spark plug gap should be between 0.7 and 0.8mm.

Measuring the gap.

Measuring the gap.

Take the spark plug gap tool and select a feeler sized somewhere within the spec. For example, I like to use the 0.76mm feeler on the particular tool that I have. Gently run the feeler between the contacts on the plug. The feeler should slide between the contacts with a slight resistance.

If the gap is too narrow, use the special tool to very gently push the contacts apart. Think “nudge” instead of pry. You shouldn’t feel anything move.

Slight pressure is all you need to change the gap on a spark plug.

Slight pressure is all you need to change the gap on a spark plug.

If the gap is too wide, use the tool to push the contacts together. Remember, gentle is the way to go. It’s extremely easy to over-do the adjustment.

The phrase “slight resistance” is standard shop manual verbiage. Unfortunately, it’s also open to a particular person’s notion of the word “slight”. To really double check the gap, measure it using a feeler that’s within spec, then select the next bigger size and try to run it through the gap. If the gap is correct, the bigger feeler won’t fit. For example, I measure against the 0.76mm feeler. The next size up is 0.83mm, which is out of spec. If the 0.76mm feeler fits and the 0.83mm one doesn’t, I know I’m close enough for government work.

Once the spark plug is gapped, rub the threads with anti-seize compound, which will help prevent the threads from sticking inside the cylinder head and make it easier to remove the plug in another 7500 miles.

A little anti-seize can save you headaches later on.

A little anti-seize can save you headaches later on.

Now, take the new plug and thread it into the cylinder by hand. Keep tightening the plug until it’s finger tight, i.e. when you start to feel resistance like it’s finally tightening up. Take the socket and ratchet and turn the wrench an additional 1/2 turn. Do not over-tighten! If you have a torque wrench, the spec is 11 N·m (1.1 kgf-m, 8.0 lb-ft).

The new plug.

The new plug.

Replace the rubber boot, pushing the cap on firmly until it snaps into place on the plug. Front plug A is done.

Remember these basic steps, because we’ll be repeating them three more times for plugs B, C, and D.

  • remove plug
  • gap new plug
  • apply anti-seize
  • insert and tighten new plug
  • replace rubber boot

Now it’s on to plug B. This one’s trickier because there’s not a lot of room to work with between the cylinder and the radiator. I recommend moving to the left side of the bike to tackle this one.

Disconnect the wire to the horn to give yourself a little more room.

Horn with disconnected wire.

Horn with disconnected wire.

Grab the plastic cap on the plug and give it a strong pull until the rubber boot comes free.

Front plug B's rubber boot.

Front plug B's rubber boot.

Here’s our target:

Front plug B is down in this hole.

Front plug B is down in this hole.

Grab your 5/8 inch spark plug socket and the 3 inch extension bar. Attach the socket to the extension, then insert the socket into the hole. If there’s not enough clearance, separate the socket from the extension, put the socket part-way into the hole, then attach the extension.

A 3 inch extension is required to reach front plug B.

A 3 inch extension is required to reach front plug B.

Once the socket and extension are in the hole, slowly and gently spin the end of the extension by hand until you feel the socket match up with the plug.

Turn the end by hand until the socket matches up with the plug and stops spinning.

Turn the end by hand until the socket matches up with the plug and stops spinning.

Now, you can use the ratchet to loosen the plug.

Loosening front plug B.

Loosening front plug B.

Once the plug spins freely, detach the ratchet and spin the extension by hand until the plug comes free.

Check the gap on the new plug and apply anti-seize. Replacing this particular plug has some added complications: you can’t see the actual spark plug hole in the cylinder head and you can’t reach it either. The solution is to essentially reverse the steps you took to remove the old plug.

First, push the new plug into the spark plug socket so that the electrode end is barely sticking out. Then, insert the socket into the hole before connecting the 3 inch extension bar. Now, use your fingers to tighten the new plug. If you’re careful, you’ll feel the new plug align itself properly and then start to tighten. The threads should turn smoothly. If you feel something catch, STOP. Back the plug out, then try again.

When the extension is finger tight, use the ratchet wrench to tighten the plug an additional 1/2 turn. Put the rubber boot back into the hole and push the cap until it snaps on to the new plug.

Re-connect the horn wire, push the radiator back into place, then replace the mounting bolt. Don’t forget to put that pesky plastic fender back too!

Two plugs down, two to go.

Step 4: Lift the Gas Tank

The gas tank must be lifted in order to access the rear plugs. You have two choices: remove the gas tank completely, or simply lift the tank up on its hinge. Removing the gas tank takes a little longer, but it makes accessing the rear plugs so much easier that I strongly recommend it. Here are step by step instructions on how to remove the gas tank on an SV650.

If you choose to lift the gas tank, you’ll still need to remove the seat. Use the 4mm hex (allen) bit to loosen the 2 bolts on the plastic trim covers below the seat. There’s a cover on each side of the bike. Remove both covers and set them aside.

asdf

A 4mm hex bit will loosen the bolt on the trim cover.

Then, use the same 4mm bit to loosen the 2 tank bolts. I like to use a T handle bit driver to reach these bolts.

My trusty T handle bit driver.

My trusty T handle bit driver.

Whatever you do, don’t drop your bit around this part of the bike!

Whatever you do, don’t drop your bit around this part of the bike!

Next, use the 6mm hex bit to loosen the 2 bolts holding down the seat. There’s one on each side of the bike.

A 6mm hex bit will loosen the bolts on both sides of the seat.

A 6mm hex bit will loosen the bolts on both sides of the seat.

Once the seat is loose, lift it up by the edge closest to the gas tank, then pull the seat forward until it slides free. Remove the passenger seat and grab the gas tank prop. Use it to prop the gas tank up by one of the tank bolt holes.

Step 5: Replace Rear Spark Plugs

Now you’re ready to tackle rear plug “D”. (Don’t worry, I’m saving plug “C” for last!) Rear plug D is tucked under the reserve coolant tank on the left side of the bike.

Hope you have small hands!

Hope you have small hands!

Take a deep breath because this one's a colossal pain.

Take a deep breath because this one's a colossal pain.

As with the other plugs, remove the rubber boot by pulling on the plastic cap. You can try gently pushing the coolant and fuel hoses aside to give yourself some room.

Rear plug D with rubber boot removed.

Rear plug D with rubber boot removed.

You’ll need the 6 inch extension bar to reach the plug. Attach the socket to the extension and thread the socket down through the various hoses until you reach the vicinity of the plug.

Threading the socket down through the hoses.

Threading the socket down through the hoses.

If you look through the gap in the frame, you should be able to see if the socket has matched up to the plug while moving the end of the extension bar around with your hand.

Look through the frame while moving the end of the extension.

Look through the frame while moving the end of the extension.

Use the socket and ratchet to loosen and remove the plug.

Gap the new plug and apply anti-seize. Just like the previous plug, you’ll need to reverse the steps you took to remove the old plug in order to install the new one. Start by inserting the new plug into the spark plug socket, then use the 6 inch extension to “fish” the new plug into place. Carefully tighten to finger tight, then use the wrench and give it another 1/2 turn.

New plug peeping out from behind a coolant line.

New plug peeping out from behind a coolant line.

Replace the rubber boot and push it into place. Then, run inside and grab a cold beverage because you deserve it.

The final plug, plug C, is much easier to get to.

Rear plug C is easily found on top of the rear cylinder.

Rear plug C is easily found on top of the rear cylinder.

Remove the rubber boot.

Rear plug C with rubber boot removed.

Rear plug C with rubber boot removed.

Use the 3 inch extension and socket to remove the plug.

As with the previous three plugs, gap the new one and apply anti-seize. Reverse the steps you took to remove the old plug: put the new one into the socket, use the extension to put it in place, then carefully tighten it finger tight and use the wrench to tighten another 1/2 turn. Replace the rubber boot and push the cap into place.

Step 6: Just a Test

Before buttoning everything back up, try starting the bike. Then, let it run for a few minutes. You should feel the front and rear cylinders begin to warm. That’s a very good sign.

Step 7: Lower Gas Tank and Replace Seat

If you chose to remove the gas tank, instructions for putting the tank back on can be found on my step by step instructions on how to remove the gas tank on an SV650.

If you decided to simply lift the tank, remove the gas tank prop and lower the gas tank. Replace the 2 bolts at the front of the gas tank. Put the seat back on and replace the 2 seat bolts. Push the side trim covers back into place and replace the 2 side cover bolts. At this point, everything should be back together again.

Summary

Tools:

  • 5/8in spark plug socket
  • ratchet wrench
  • 3in and 6in extensions
  • 10mm wrench
  • spark plug gap tool
  • hex (allen) bits or wrenches: 4mm and 6mm
  • bit driver

Consumables:

  • 4 spark plugs (NGK or DENSO)
  • anti-seize compound

Optional:

  • torque wrench
  • 2×4 block of wood to prop radiator away

Spark Plug Gap: 0.7 to 0.8mm
Spark Plug Torque: 11 N·m (1.1 kgf-m, 8.0 lb-ft)

  1. Remove radiator fender, loosen radiator and pull it toward wheel.
  2. Remove right front plug.
  3. Remove left front plug using 3″ extension.
  4. Gap new plugs, replace and tighten to specified torque.
  5. Remove seat and lift gas tank.
  6. Remove right rear plug using the 3″ extension.
  7. Remove left rear plug (located under reserve coolant tank) using the 6″ extension.
  8. Gap new plugs, replace and tighten to specified torque.
  9. Replace gas tank, seat, radiator, and radiator fender.

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{ 18 comments… read them below or add one }

1 Mike October 7, 2009 at 5:54 am

Great. I need to change my plugs. I also am due for the 1st valve check. Hopefully that wont be too expensive.

Reply

2 steadyonthehumble October 7, 2009 at 7:51 am

Wow, what a great DIY post, I’m thoroughly impressed! I don’t have a naked bike like your SV but by the looks of it, my fully faired bike looks A LOT easier to change the plugs on, rear cylinder and all!

Reply

3 Stacy October 7, 2009 at 9:15 am

@Mike: I’ve heard that the valve check is not too difficult. I need to check mine too. I’ve got a couple of friends who’ve volunteered to come over and help me with it. Maybe I can write up another guide.

@steadyonthehumble: It used to be much easier, that’s for sure. Pre-2007 SVs only have two plugs, and both are pretty easy to reach. Now there are 4 plugs, 3 of which are deep inside the cylinder. Lifting the gas tank is cake once you’ve done it a few times, and on the SV, you’ll be lifting the tank a lot.

But yes, this is an hour and a half (or maybe an hour long) job. Changing the plugs on my Rebel took 5 minutes!

Reply

4 LifeOn2Whls October 8, 2009 at 3:41 pm

Ugh. I’m well over 8,500 miles and still haven’t changed the plugs on my ’09. Will get to it eventually but not something I am looking forward to. Great write up and will be very useful when I am ready to tackle this. The cylinder heads on my old CX500 stuck out the side like a Guzzi so everything was exposed…how I miss that and the shaft drive.

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5 cpa3485 October 10, 2009 at 7:57 am

Thanks for posting this. I have been leery to do maintenance work on my scooter, just because of the belief that it is an unusual engine. I used to do much of my own maintenance on some older volkswagons that I owned, including tune ups, valve adjustments, and other repairs. Reading this gives me a little more confidence that maybe I shouldn’t be so timid about tackling some chores on my scooter.

Reply

6 Stacy October 13, 2009 at 10:42 am

@LifeOn2Whls: 7500 miles is extremely conservative. I’ve heard quite a few folks use the same plugs out to 20k or even 30k miles. For the purposes of this guide, however, I’m going to stick with the party line — the maintenance chart in the owner’s manual.

@cpa3485: I’m a maintenance newbie, so I’m only confident in doing the basics. I’ve found that a service manual helps, as does a strong user community (like a forum or website).

I’m keeping my eye out for a cheap basket case so I can try cracking open an engine without worrying about fubar’ing my primary ride.

Reply

7 Carlos October 15, 2009 at 8:15 am

Whew. I was beginning to freak 0ut!

My 04 SV only has two plugs, both of which I changed at the beginning of the season. I was beginning to think I missed two plugs. :)

Nice writeup!

-Carlos

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8 Stacy October 15, 2009 at 11:11 am

@Carlos: You lucky dog. As you can see, if you have a 2007 or newer SV it’s quite a pain.

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9 Murray December 2, 2009 at 11:42 pm

Changed the plugs on my 2007 SV650 at just under 12,000 KM in August 2009. At that time, I hadn’t come across this site yet so I just went by what the manual said. Plugs were still in pretty good shape. I was able to change them myself without too much difficulty but I doubt that I’ll try the valve adjustments myself. I’m looking forward to the next article on how to do the valve adjustments though.

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10 Pedro187 December 6, 2009 at 9:57 am

I have the W reg SV 650 fully faired only had it 2 weeks have been an in line four man all my life and heard great things about the 650 as a commuter , i also have a 99 firewblade.

As i said have had the 650 for 2 weeks and all of a sudeen it has started back fireing, after the fuel getting low one day , it may have sicked something up so have run some carb cleaner throght the tank but it still seesm to be there.

I am going do the plugs and although the rear look easy enough i dont really liek the idea of having to take all the fairing off and dropping the Rad , does anyone know if i have empty the rad to do this?

Kind Regards

Reply

11 Stacy December 6, 2009 at 11:16 am

@Pedro187: You do not have to drain the coolant before unbolting the radiator. You’ll only need to move the radiator aside a couple of inches — just enough to get your socket in there to reach the plug.

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12 Stan April 4, 2010 at 5:10 pm

Awesome post! Was able to do it in about an hour today and I’m a beginner! :)

Reply

13 giest April 18, 2010 at 3:46 pm

Wow…those are some really interesting spots to put spark plugs! Fantastic guide you’ve wrote up there.

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14 Stacy April 19, 2010 at 11:38 am

@Stan: Good work!

@giest: Thank you. The plug locations are indeed awkward, but at least the bike doesn’t have any tupperware to deal with.

Reply

15 mr bill October 1, 2010 at 8:20 pm

Stacy, thanks for the great article. I just got 4 plugs air filter and some chain degreaser for $70, I think I can do better next time. Plan to tackle the plugs this weekend, your article gives me the added info I need to keep me from swearing like an old sailor…. we’ll I guess that’s what I am. :-)

Reply

16 mr bill October 21, 2010 at 3:02 pm

Stacy, I followed your directions, finished up in about an hour. On my 2007 SV650 I wound up removing both radiator mounting bolts so I had a clear shot at the center plug. The worst part for the the side plug under the tank was that I couldn’t reach in good enough to hear or feel the wire snap back on the plug, but it is running well so I must have gotten it on.
thanks,
mrbill

Reply

17 Double T May 4, 2011 at 5:34 pm

HI !! Just wanted to say how great the write ups here are. So far Ive used the chain cleaning write up and the spark plug change. I would not have even tried the plugs without your write up. Up next Im going to do the antifreeze change. Thanks for saving me a decent amount of money by allowing me to see how easy these procedures are.

Reply

18 Stacy May 4, 2011 at 6:18 pm

Double T,

You’re welcome. :)

Reply

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