spark plug reading

[hurleyfrank]

Hi all! I've got some question about spark plug reading since i fear that i run lean and that my engine will suffer someday.

Background: month ago, i installed K&N drop ins+ cobra slipons, i had to change the A/F screw setting to rebalance the whole thing. I kept the old NGK iridium spark plugs. It did run well for a while, until i changed the A/F setting of the front (seemed too lean) and fouled it by ''unscrewing'' it too much(misfires, black plug, you get the idea...)

Now: i changed my plugs for the normal Cooper NGK (supposed to be better) and ran for 300 miles (montreal-lake george,NY and back). Pulled em: only color i get is on the ring; almost nothing on the ''leg'' or the '' white ceramic'' around the electrode. Only blackish color was on the ring of the spark plug just under the thread.

Question: Am i supposed to read it on the thread or on the ''ceramic'' part? How many miles before i take a reading?

I really suck at reading those... any help appreciated! Right now, from the picture i get from google i can't really say.

AND ILL SEND PICTURE OF EM if you tell me how many miles i should do!

Thanks.

[enforcer]

You basically read the whole firing end of the plug. And you do so after a WOT chop. Only way to get a very accurate reading.

Or you can get a slightly less accurate reading after a few hundred mile ride. Never remove or install a spark plug from a warm motor. It may cross thread or you won't get the torque right and once it cools down, the plug will seize. Very expensive to remove.

[JamesC]

I love the threads you supply 98VS1400; they are so practical and helpful. Thank you, Bro. You da man! Enforcer is also a fountain of knowledge. I salute those who help others by being selfless, not selfish. Bravo.

[hurleyfrank]

wow, thanks guys! I was TOTALLY wrong in my way of doing it! now, i need a highway or something to open to WOT....and where i can stop on the side to remove spark plugs....but not reinstall them in the hot engine to not seize them. CRAP, that sucks! XD

[enforcer]

wow, thanks guys! I was TOTALLY wrong in my way of doing it! now, i need a highway or something to open to WOT....and where i can stop on the side to remove spark plugs....but not reinstall them in the hot engine to not seize them. CRAP, that sucks! XD

It's easiest to do on a rolling road or with the rear tire lifted .

But barring that, a few hundred miles is sufficient.

[hurleyfrank]

If i lift the rear tire; it wont hold WOT for 1 second before i hit the rev limiter. Is it how you guys do it?

[enforcer]

If i lift the rear tire; it wont hold WOT for 1 second before i hit the rev limiter. Is it how you guys do it?

Your rev limiter is your WOT in a sense. There's no way to achieve WOT with one. A Dyna 3000 allows you to raise it, but there's no way to completely remove it.

[hurleyfrank]

Yes. My point being that if i hit the rev limiter, the CDI will not send pulse to coils, that wont produce spark to sparkplugs. If i miss one explosion every 2-3 rotation, the plugs will look like it's running rich, right? I could be mistaken on that one....

[Spitfire]

wow, thanks guys! I was TOTALLY wrong in my way of doing it! now, i need a highway or something to open to WOT....and where i can stop on the side to remove spark plugs....but not reinstall them in the hot engine to not seize them. CRAP, that sucks! XD

No man, you need to go back and reread that post. You never remove or install plugs in a warm engine. Removing them while it's hot will cause them to pull the threads out, installing while it's hot will cause it to be seized later. Aluminum heads are really bad about this, never work on the plugs while the engine is warm or hot.

[hurleyfrank]

*remove spark plug once the engine cooled down*

[enforcer]

See what I mean about all the help getting confusing???

I make suggestions about how I or others perform plug readings. I gave another option.

Plug readings are a poor man's way to adjust the a/f mixture. No matter how accurate, it will never be perfect. The only way it will be perfect is a few dyno runs and sniffers in the mufflers.

I've always adjusted mine by blipping the throttle and listening to the engine. Hard to get it perfect with dual carburetors. That's why when I did it on my Intruder I did one cylinder at a time, by pulling the plug cap on the other cylinder.

By adjusting it without pulling the plugs, you can get it close, ride her a few hundred miles, pull them when you get home and fine tune.

I've never once heard anyone say they set their a/f mixture correctly on the first try. It takes time to work it out.

But when you do, man does the bike run sweet.

[enforcer]

I wasn't criticizing you. Your advice was sound, it's just that apparently, the various advice became confusing to the reader. That was my experience in the past as well. I'm not the brightest guy in the world, so I seek out very simple methods for doing anything. Unfortunately, when it comes to carburetors, not much is really "simple".

Unless you only have one. [emoji2]