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.

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. Unfortunately, this particular part just happened to fall off my bike sometime this summer and I’m still waiting for a replacement. Here’s a picture of it from the service manual (marked with “1″):

Use a 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.)

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.

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.

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

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

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

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.

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.

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).

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.

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

Here’s our target:

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.

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.

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

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, and to do that, you’ll also 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.

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.

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

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.

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.

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.

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.

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.

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.

Remove the rubber boot.

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

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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Tagged as: howto, maintenance, Motorcycling, spark plugs, SV650