What do these spark plugs say to you?

[Guest]

As the title implies.

The bike runs fine. I just had the tank off to do other repairs and figured I'd take a look at the plugs. Keep in mind this is one of those 2-2barrel carb bikes.

I have Dyna 3-ohm ciols with 7mm 1964 VW-Beetle solid core wires and NGK 5K ohm plug ends with D9EA plugs. Just curious if the center 2 cylinders are lean for street riding to you guys. (If these came out of one of my stock cars I'd lean 1 and 4 about 1 turn and lean 2 and 3 out about 1/4). I'm thinking 1 and 4 are about 1/8 rich and 2 and 3 are about 1/4 lean for air cooled street riding.

Thanks in advance for your opinions.........

(Links to pics of my coil install and carb settings)

http://i510.photobucket.com/albums/s350/donmod/DSC00088.jpg

http://i510.photobucket.com/albums/s350/donmod/DSC00087.jpg

http://i510.photobucket.com/albums/s350/donmod/DSC00085.jpg

[BassCliff]

Hi,









#2 and #3 look lean to me too.


Thank you for your indulgence,

BassCliff

[don]

Curious to know your opinion of 1 and 4. Looks to me like maybe a little oil. But as usual, I don't have the intimate experience with these bikes to know what's ok or not.

I humblly accept and respect yours.......

[don]

Oh, and by the way, I posted a pic of my crispy stator in the other ( electrical forum ) post for your gloating enjoyment. lol Fried the wires clean off of the stator coils.

[hikermikem]

I thought you shouldn't run resistor caps with Dyna coils...

2 & 3 look lean to me too...

[SqDancerLynn1]

I thought you shouldn't run resistor caps with Dyna coils...

2 & 3 look lean to me too...

It depends on what type of wires you use. Solid core YES resistor caps
Suppression wires use auto type ends
2&3 definitely lean

Could you have the jets mixed up ?? center two are jetted different

[don]

No, the jets are in the correct places. I had problems for most of last year and had the carbs apart a mere 100 freakin million times.

No one has commented on the outer two. I'm guessing they look good??

[almarconi]

It has always been my understanding that in order to correctly read the plugs, you need to "chop" them (cut off the threaded part) and look at the area further up the insulator. Chef1366 recently displayed some pics of some properly chopped plugs.

[BassCliff]

Hi,

Yes, don. I'd be happy with the color of those outer two plugs.

I suspect that these colors are at idle. Plug chops at each throttle opening (1/4, 1/2, 3/4, wide open) will tell you more.

I saw your stator. Man! That's one I haven't seen before. Burnt those wires clean off!


Thank you for your indulgence,

BassCliff

[FlyingSteve]

2 and 3 look fine from the base rings... They have a nice full turn of gray color. However, it's not possible to see down to the fuel rings in those pics, which would be another indicator of A/F ratio.

1 and 4 look slightly rich, most likely at idle based on the base ring color and the color at the top of the ceramic which fades to a whiter color as you move away from the center electrode. It's hard to tell about the heat range from the pics, but looking at the plug on the far right, it appears that the color change on the ground strap is happening right at the bend in the strap, which is the proper place. I can't see a color change on the other 3 plugs though.

I'm not certain how you guys are coming up with your "too lean" verdicts...

[BassCliff]

Hi,

For what it's worth...

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

Thank you for your indulgence,

BassCliff

[Mekanix]

As I understand it.

1 carb is for # 1 and 2 cylinder
the other is for 3 and 4

So 1 and 2 should be getting the same mixture.

And 3 and 4 should be getting the same mixture.

So plugs 1 and 2 should be the same and,

3 and 4 should be the same.

The only reason I can think of that would cause this is intake seals on 2 and 3 getting hotter and deteriorating or valve adjustment.

[Steve]

As I understand it.

1 carb is for # 1 and 2 cylinder
the other is for 3 and 4

So 1 and 2 should be getting the same mixture.

And 3 and 4 should be getting the same mixture.

So plugs 1 and 2 should be the same and,

3 and 4 should be the same.

The only reason I can think of that would cause this is intake seals on 2 and 3 getting hotter and deteriorating or valve adjustment.

Yes and no.

You are right about one carb servicing two cylinders, but the only thing they share is one float bowl and one diaphragm that lifts both slides. There are still two separate throats and individual jets for each throat.

Knowing that, the rest of your logic train just derailed.

.

[FlyingSteve]

Hi,

For what it's worth...

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp

Thank you for your indulgence,

BassCliff

http://www.4strokes.com/tech/sparkplg.asp

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

http://forums.bimmerforums.com/forum/showthread.php?t=1282968

Bass, those links you posted have lots of nice pictures with little "one size fits all" explanations, but they do not tell or rather teach you how to actually read all the different parts of a spark plug. That would be like sizing a book up by it's cover.

Enjoy!

[KEITH KRAUSE]

2 and 3 look lean to me. 1 and 4 look better but the shiny black areas would be oil burning.
What throttle position did you chop off at to get these reads? Were they removed after the bike idled some? Was the motor hot or still cold?
The electrical issues you mention need fixing first.
I'm not familiar with your carbs so I can't offer much other than the usual to be sure all parts are clean and checked for wear and correct size jetting. Check all rubber parts too. If all is good then the mixture screws are all you have to change the mixture. Hook up a vacuum gauge to check vacuum levels.