Topic: Strange plug reading

[pmpski_1]

I pulled my plugs to read them today. One of the plugs had the nice tan color on the electrode on one side, while the other side was carbon fouled. Seems strange. Any ideas or explanations?

[kghost]

Hmmm....

One cylinder has bad rings or valve seals the other doesn't?

[pmpski_1]

This is on the same plug! I should have gotten a picture of it. All of my plugs are reading differently, but that's another post ... 

[77F2cb]

Tan means lean....a light greyish color would be correct.  The others are rich, are they fouling (that means not firing), or just sooty, or wet? Is the bike ridible or worse?

[pmpski_1]

Sorry guys, I know this is strange - One side of the same plug is different than the other side. 

I removed the number 1 plug. I was happy to see a nice tan color as opposed to the normal carbon fouling that I have been seeing. I looked at the other side of the plug and it was still carbon fouled.

On one side of the electrode it's tan, on the other side it's black. I'll try for a pic tomorrow.

I cleaned these plugs yesterday and rode for about 10 miles today.

[TwoTired]

I don't understand.  Did you clean the plugs before attempting to get a new reading?
Or, were they sooty, tuning changes made, and then read again after a ride?

Could they be in the process of self cleaning but haven't achieved uniformity yet?

Perhaps you need to index your plugs?

[MRieck]

You could have a condition of a rich main jet/needle to high but correct air screw setting. What this will do is when cruising at light throttle,ie, highway, you are burning clean. Get on the throttle and the plug begins to foul. You have to look deep in the plug to get a real reading and you will need a light and magnifying glass(or a plug reading tool). Looking around the ground electrode doesn't give you a good reading. If all the cylinders are burning a lot differently you could have worn parts in the carbs, ie needles, needle jets or float needles(or a combination). All cylinders will burn a little differently especially with modifications to the exhaust and the addition of individual filters etc. What type of ignition are you running? You could try a hotter plug if evertything else is in order.

[pmpski_1]

They were sooty before riding. I cleaned the carbs, then I cleaned the plugs (they were carbon fouled) and rode around for a bit. I guess this is more of a weird phoenomenon than a problem. In fact this was the best plug out if the 4.  I tried to get some pics of it tonight but they turned out bad and out of focus. You can't see it very well.

My bigger problem is the oily plugs on 3 and 4. The manual says that you can use a hotter plug if you don't want to put in new rings right away. I don't want to do the rings until the weather starts getting worse, so I'll try the hotter plugs for now.

[Bob Wessner]

They were sooty before riding. I cleaned the carbs, then I cleaned the plugs (they were carbon fouled) and rode around for a bit. I guess this is more of a weird phoenomenon than a problem

If I'm reading your description correctly, I ran into this same problem while trying to sort out the idle mixture on my bike. The side opposite the electrode was sooty and on the electrode side there was this 'patch' that appeared pretty clean with what seemed like the correct color, etc. What I found was this was an indication I was getting close on the mixture. I turned the airscews out just a touch more and the correct color appeared over the entire plug. All I could figure was as you get close to the correct idle mixture the side opposite the ground electrode must be slightly cooler??, just my guess, have no clue if it's correct, but leaning out a hair did the trick.

[pmpski_1]

Yep Bob, that sounds about right. I'm glad it's getting closer.