Author Topic: How do these plugs look?  (Read 835 times)

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Offline sparty

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How do these plugs look?
« on: October 21, 2007, 01:39:26 PM »
Guys,

I pulled the plugs after today's ride.  I thought that I was running a bit rich, but the plugs look like I might be running just right.


Sparty
1972 CB750 K2 Cafe' Style




GO AWAY SNOW AND COLD!  Can you see the Hot Rod wants to run...
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Offline TwoTired

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Re: How do these plugs look?
« Reply #1 on: October 21, 2007, 01:43:16 PM »
They don't look bad as a general run subject.  But, need a clearer, in focus picture of the strap and a look deeper into the plug at the insulator.

Was this all throttle positions?
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline sparty

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Re: How do these plugs look?
« Reply #2 on: October 21, 2007, 01:58:30 PM »
They don't look bad as a general run subject.  But, need a clearer, in focus picture of the strap and a look deeper into the plug at the insulator.

Was this all throttle positions?

Those are the best pics my camera will take.  Throttle position was all over the place except WOT.  The insulator looks similar deeper into the plug.  I am most likely just a tad rich looking at some of the carbon on the skirt.  The strap is a bit brown from the tip to about half way.
1972 CB750 K2 Cafe' Style




GO AWAY SNOW AND COLD!  Can you see the Hot Rod wants to run...
“That's thirty minutes away. I'll be there in ten.”

Offline TwoTired

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Re: How do these plugs look?
« Reply #3 on: October 21, 2007, 02:39:50 PM »
On an air cooled motor running at anything but WOT throttle only, you can expect the outer ring to be black always.  That is, if the cooling fins are doing the proper job of cooling the engine.  Then the temps at the base ring will not support combustion.

Have you gotten past the initial oil consumption of ring break in?  Those deposits could brown plugs some, I think.

I would look into the insulator. The base of it could be carboned, too.  Perhaps up to a third for multi throttle positions.

Slightly on the rich side helps cool the engine during break in while the friction is a bit higher.

Cheers,

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.