Spark Plug Reading - What's your read?

[MelodicMetalGod]

Here's a pic of the plugs in question:



According to the following images,

http://www.gnttype.org/techarea/engine/plugs.html

I'm thinking that the read is that my plugs are in the early stages of carbon fouling.

Would you agree?

Thanks for your time!

[Dave8338]

I disagree...if anything, they are slightly lean (not much) but IMHO, along way from fouling out.

[NickNoo]

Yep - perhaps a tad lean, but nothing to worry about.
Have a look here for some good spark plug info : http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

[denydog]

They look kind of new. I don't see any fouling of the electrodes and insulators. They look a lot like mine. I'll vote for slightly towards the lean side also.

[DimitriT]

I agree with everyone else

If you pulled these from a normal shutdown (idling) bike they are normal. The idle is a bit lean on these bikes but that's ok so long as your choke can start the bike. You don't want lean when your bike is on the main jet (with the throttle way open) as you can damage your motor.

[MelodicMetalGod]

OK, so it looks like I was reading it wrong. Guess it's a "Lean" read then. Well, I've got very little experience reading plugs and that's why I posted.

Thanks everyone!

[MelodicMetalGod]

I agree with everyone else

If you pulled these from a normal shutdown (idling) bike they are normal. The idle is a bit lean on these bikes but that's ok so long as your choke can start the bike. You don't want lean when your bike is on the main jet (with the throttle way open) as you can damage your motor.

Yep, lot's of idling and then I pulled the plugs. Still have some carb tuning to do. Now I have a good read to work from. Thanks!

[rustybronco]

Some more reading...

http://faq.f650.com/FAQs/SparkPlugFAQ.htm#Plug%20Chop

http://www.nightrider.com/biketech/readplugs.htm

http://www.4secondsflat.com/Spark_plug_reading.html

MORE... http://www.dragstuff.com/techarticle...ead-plugs.html

if this doesn't fill your head, nothing will.

[Steve]

The outer edges of the plug do have black stuff on them, but that's not where you read them. :shock:

You read the porcelain cone in the middle that holds the electrode.
They are mostly white, with beginning tinges of tan, indicating slightly lean, but not enough to worry about.


.

[rustybronco]

Did you read the section about dividing the the center insulator up into three parts yet? how about reading for timing?
there is a lot to know about what effects what, such as a rich condition leaving the insulator white from fuel washing it clean, and the tan on top 1/3 not going all around.
how about way down where the insulator is near the shell that tells w.o.t. mixture.
there is a LOT to know my friend, and if you can grasp it all you're better than me!!!!!!!!!

yes steve imho is correct. thats how i read it also.

[steve-lloyd]

I would say they are more than a little lean.
The really important test is to run the bike hard at full throttle, uphill if possible, then cut the engine on the kill switch. Now remove the plugs.
The part of the plug you need to inspect is the centre cone shaped part, which should be light to dark tan.
White is dangerously weak, grey is weak, dark tan/brown is rich, and black is very rich.
Many Suzukis are running around too lean, because owners fit pods on the carbs instead of the standard airbox and filter without rejetting and readjusting the carbs.
GS bikes hate being meddled with like this and are very difficult to get running really well with pods.

[MelodicMetalGod]

rustybronco,

Thanks for the light reading. I have now decided to go back to school full time to major in Spark Plug Reading. First Course: Shades of Tan and What They Mean.

Seriously, very informative. Thanks.

[MelodicMetalGod]

Steve, thanks for taking a peek. Reading the porcelain I noticed that plugs 1 & 2 are showing tan where 3 & 4 are very clean. Could that be from carbs that aren't synched (which mine aren't yet)?

[MelodicMetalGod]

I would say they are more than a little lean.
The really important test is to run the bike hard at full throttle, uphill if possible, then cut the engine on the kill switch. Now remove the plugs.
The part of the plug you need to inspect is the centre cone shaped part, which should be light to dark tan.
White is dangerously weak, grey is weak, dark tan/brown is rich, and black is very rich.
Many Suzukis are running around too lean, because owners fit pods on the carbs instead of the standard airbox and filter without rejetting and readjusting the carbs.
GS bikes hate being meddled with like this and are very difficult to get running really well with pods.

Haven't really done much at full throttle yet. Mostly suface street driving (mid-range) and idling. I've got a stock airbox, but I suspect that I've had an air leak at the intake boots. In addition, I've got two pilot screws that are stuck and stripped out and I was running the other two about 1.5 turns out.

I'm thinking that I need to do the following:

1) Get the two stuck pilot screws unstuck and set all screws to 3 turns out.

2) Ensure that I've got an air tight system from the air box to the cylinders.

3) Sync the carbs.

4) Tweak #1 as needed based on future reads.

Sound about right?

[twistedwankel]

Yep. Those are spark plugs. They work better in the head. "Reading" is that you will meet a short dark stranger on a moonlit road in August. He will tell you where to go.