Reading (Another) Spark Plug

Faded

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Jan 7, 2003

842

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• Apr 14, 2003

• #1

Pulled this plug out of a '98 CR250 (36:1 w/pump). Was wondering what peoples options were on rich/lean conditions. Looking for help deciphering what I'm seeing.

 

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T

TRAIL

Member

Nov 12, 2002

119

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• Apr 14, 2003

• #2

it looks pretty close to me.

 

Jaybird

Apprentice Goon

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Mar 16, 2001

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Charlestown, IN

• Apr 14, 2003

• #3

Faded,
If you infact did a WOT and chopped the throttle and kill switch simultaneously, I would say you are on the rich side. Not a bad thing perhaps, but probably room to get closer to the raged edge of lean.
I'm basing this on the fact that there is more than a mm of carbon at the seat of the porcelin.
You could probably accomplish a closer tune with a change of fuel and/or oil ratio easier than fiddling further with the main jet. Were atmospheric conditions close to what you normally ride in?
You are getting close....how does the bike perform for you at this point, is probably the best question to ask.

 

Faded

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Jan 7, 2003

842

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• Apr 14, 2003

• Thread starter
• #4

It's not mine, I posted it for another user. Hopefully I can get him in here to describe riding conditions and how it felt.

 

bedell99

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May 3, 2000

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• Apr 14, 2003

• #5

I think the heat range of the plug is fine. I would say that it is a little rich on the main jet due from the base of the insulator plug. He might be able to go down 1 step on the main and be alright.

Erik

 

F

Fark

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Aug 12, 2002

438

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• Apr 14, 2003

• #6

How can you guys say the heat range is OK? I was under the impression that you tell that by looking at the pits on the center conductor. Or if the edge is jagged, go down. Kinda hard to tell on-screen.

 

S

shifting

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Mar 5, 2003

114

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• Apr 14, 2003

• #7

The plug is a BR8EG NGK. Problem was it started snowing before we got where we were going and temp. was around 33 degrees. We were at the dunes and didn't have the means (safely) to rejet or even think about messing with our carbs. I wanted to drop the main one size but figured richer is better at the dunes anyway. To say the least, it ran like crap!! It felt like I was running way rich. Just for anyone elses sake, DON'T RIDE THE DUNES WHEN THERE WET. YOU WON'T BELIEVE WHAT IT DOES TO YOUR BRAKES.
NO, WHAT IT DOES TO YOUR WHOLE BIKE!!!!!! :whiner:

 

M

Moto Squid

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Jul 22, 2002

853

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• Apr 14, 2003

• #8

how'd you bust the plug apart?? I'd end up shattering everything.....

 

Faded

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Jan 7, 2003

842

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• Apr 15, 2003

• Thread starter
• #9

One of them cordless wizard things, small cutting wheel attachment, and nothing else to do for a while...

 

J

jmutiger

Member

Oct 10, 2001

169

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• Apr 15, 2003

• #10

In my opinion, that plug is being run too lean.. That's my opinion..

If my bike looked like that, I would be looking to richen it up.

Jon!

 

Jaybird

Apprentice Goon

LIFETIME SPONSOR

Mar 16, 2001

6,449

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Charlestown, IN

• Apr 15, 2003

• #11

jmutiger, If your bike looked like that, it would be a spark plug.
Sheesh.

 

S

Studboy

Thinks he can ride

Dec 2, 2001

1,818

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• Apr 15, 2003

• #12

jmutiger,

Are you looking at the correct area of the spark plug?

 

F

flynbryan

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May 22, 2000

1,066

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• Apr 16, 2003

• #13

That is something I wanted to ask ya'll. What is the proper area of the plug to be looking at for the color of the plug indicating a correct jetting? I always thought it was the porcelin and the (forgive the term,but I'm having a brain fart :) ) metal tip at the end(electrode?) of the porcelin. My plugs end up w/ a very cleanly burnt(no carbon) on the arm that goes over top of the plug and the porcelin and electrode have a dark black color to them. Not wet just very dark carbon deposit. I'm also running a four stroke. Is there going to be a difference in how it should look? Can anyone post a picture of what a properly carbuerated plug should look like?

 

Last edited: Apr 16, 2003

bedell99

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May 3, 2000

788

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• Apr 16, 2003

• #14

Rich had a great thread on reading sparkplugs. Before I read that, I was reading spark plugs all wrong. The place to read a sparkplug is at the base of the insulator. All the top does is tell you is of the plug is of the correct heat range. In Faded's particular case the plug is of correct heat range and the main circuit is "little" rich. But overall the plug looks fine. With temps going up he can safely go down on the main jet. Flybryan most people don't run there bikes hard enough to heat up the insulator enough to burn away carbon deposits. You can try a hotter plug and see how that work for you.

Erik

 

F

flynbryan

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May 22, 2000

1,066

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• Apr 16, 2003

• #15

I think this will go through......I hope. Heres the plug current. I'll do some jetting changes this week and try to give some pic updates.

 

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CR-For-Ever

Member

Feb 25, 2002

166

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• Apr 16, 2003

• #16

Hmm,

If I remember the reading plug topic correct your plug looks like it could definetly go down on the main jet.

Atleast that's what I see...

 

F

flynbryan

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May 22, 2000

1,066

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• Apr 16, 2003

• #17

Yea I'm did just that and I'm gonna check it out this afternoon. I think I might even be able to lean my needle as well. I know that leaning my pilot jet out won't help as I tried this and just got a bad BLAAAA when I would ride around and then snap the throttle open quickly. Changed back to the richer jet and all was well again. So again I'm gonna give it a try in the next couple of days and get back.