| For the spark
plug gap -- go to the NGK site and look it up! |
http://www.ngk.com
(Hint: 1st category in their search tool is Power Sports) |
| For specific info on Virago spark plugs |
See
Rain's letter from November 5, 2002 |
| What does the spark plug do, anyway? |
Well, when working correctly, the spark created in the
gap of the spark plug ignites the fuel/air mixture in the combustion
chamber of the engine and drives a piston to move the rest of the
thing-a-ma-jigs inside which allows the bike to run. |
| And why do I care? |
Because most bike manufacturers have recommended
timeframes for changing your spark plugs for optimum performance
(for my bike, it's every 5,000 miles). Also, if your bike starts
backfiring, hiccupping, farting, or running rough, spark plugs are
one of the easiest things to check for problems and change even if
you're out riding. |
| So, what does one look like? |
Here they are! All shinny and new! The
top is the gap where the spark is created, and at the bottom is
where the spark plug wire is connected.
|
| They sure are funny looking. |
You would be too if you had been engineered to death!
Trust me on this -- it all really makes sense to people who know
about these things! |
| Ok, so where do I start? |
At the beginning of course! |
| Seriously! |
By determining how many spark plugs you have and
locating the spark plug wires that lead to them. Check your service
manual under the General Maintenance Section. I'll point to the two on
my bike.
|
| Ok, I found the spark plug wires. What tools do I need
to get this puppy off? |
Just your fingers -- the spark plug wires just
"pop" off the tips -- and then you'll see the skinny end
of the spark plug and the white ceramic part of it. The arrow to the
left shows the spark plug with its wire still connected. To the
right, it the spark plug with its wire off. See the white ceramic
and skinny tip poking out? Of course you do!
|
| Well that was easy. Do I get to go home now? |
Hardly! We've just begun! To inspect a spark plug, or
change it out, you'll need to unscrew it. |
| By hand? |
Nope, now you need a spark plug wrench. Something like
this:
That's the spark plug socket at the far left and it's cushioning
inner sleeve next to it (which just sits inside the socket to
cushion the ceramic part of the spark plug so it doesn't get
damaged). In order to turn the socket, you need the third part which is a socket
driver and you might want the driver extension to the far right if
space is tight. You can buy the socket individually,
or get a driver/socket/spark plug socket combination set. |
| Geez, hold it. I might have to go to the hardware
store real quick to buy one or ask someone if they'll loan me one. |
Take your time. It's important to have the right tool
for this job. |
| Ok, I'm back. |
Then let's get started. Place the socket with it's
cushioning sleeve over the spark plug. Then connect the driver (you
may want to use a driver extension piece (I find it easier to work
with then) . Now, turn the whole mess counterclockwise to loosen it.
Don't worry if the first part takes a little "oomph"
because a spark plug is tightened in. Got it? Keep turning it until
it comes out.
|
| Hey, I did it! |
Congratulations. Now it's time to figure out what
you're really looking at. |
| Such as . . . . |
Here is a picture of a baaaad plug. You're really only
concerned about the fat end, where the gap is, although you should
check the white ceramic part as well to see if there are any cracks.
Take a look: 
|
| Ugh. Who knew they could get so crudy. |
Exactly. That's the point. To understand
what you're looking at, look at the gap end.
If the gunk is black, wet and shinny, you've got an oil fouled
plug that may be caused by worn rings and pistons, loose valves, a
weak battery, faulty ignition wires, circuit breaker trouble, a weak
coil or a cold plug.
If the gunk is dry, fluffy or sooty black, that's gas fouling, a
result of a too rich carburetor air-fuel mixture, a lot of engine
idling or a cold plug.
If the gunk is dry, glassy and brown, that's an overheated plug
caused by too lean an air-fuel mixture, a hot running engine, valves
not seating, improper ignition timing or too hot a plug.
|
| So what should I do? |
Hold onto your old plugs to show your
local service person if further troubleshooting is necessary.
Meanwhile, install new plugs. |
| Just any old plug? |
Nope -- it's important to install the
spark plug that is recommended by the manufacturer of your
motorcycle. You can find this in your service manual (even the
"beginner" manual that might have come with your bike).
Or, tell your local dealer exactly what year and model bike you've
got and they'll have the specifics.
|
| I'm ready maestro. Lead on! |
The thing you have to do with new
plugs is check the gap. Even if the package says that they are
"pre-gapped," check it any way. |
| And how do I do that? |
By using a feeler gauge. They come in a
variety of styles, but here is mine:
Notice the numbers on each "piece." That's the
thickness of the piece. |
| And I have to know that because . . . |
Because the recommended gap is listed in
your service manual. Your local dealer will have the answer as well.
|
| And then I . . . |
And then you choose two side-by-side
"pieces" that add up to your gap size and you slide that
through the spark plug gap to check if it's too loose or too tight.
New plugs are usually too loose.
|
| So how do I get the correct gap? |
Well, this may not be highly scientific,
but I just gently push the top piece gently against my workbench to
snug it in a little.
You could also use a pair of needle nose pliers to bend the thing
in a little.
Then I use my feeler gauge to re-check the gap. Ideally, you
should feel a slight "drag" of the gauge as it passes
through the gap. |
| And then I just screw them back into the
slots? |
VTwin Mama sister Jan notes that it is
important to apply a coat of anti-seize compound to the threads (the
part that screws in). Anti-seize products are designed to provide an
insulating layer between the metal of the spark plug and the metal
of the casing you are screwing it into so they don't fuse (melt)
together. Any local hardware store should be able to assist you with
this purchase.
Then you can turn them in by hand
clockwise. Using the same spark plug socket, turn it gently
until it is seated all the way in and then give it one extra 1/4
turn to snug it in.
|
| What's left to do? |
Reconnect the spark plug wires. Then
start the bike to see if everything is okey dokey! |
| Wow. I did it! |
Congratulations. Piece of cake! |
| Is there anything I can do for emergency
repair on the road? |
Yes -- as long as you can get the darn
things out to check, you can always clean off the gap area by filing
off the residue. An emery board for filing nails is a handy tool!
But remember, this is only a temporary fix -- get new plugs in as
soon as you can!
|
