EVO All Evo Model Discussion

Plug color opinions

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Old May 17, 2019 | 12:02 PM
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Default Plug color opinions

So i know this is about like starting an oil thread and i apologize..... I just wanted to get your opinion on my plugs. There is about 3k miles on these. Bike runs flawless no hesitation, or coughing, or breaking up of any sort. That being said they look just a tad lean to me but i want a second opinion.

Bike is an 86 heritage. Full s&s carb and air cleaner 295 intermediate and 70 main jet. 2 into 1 pro pipe.

Motor has 10:1 pistons in it with a 561 s&s cam. Running the ultima/dynatek ignition setup.

Plug on the right is front hole. Looks perfect to me. Left is rear. Looks a touch lean maybe??


 
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Old May 17, 2019 | 12:15 PM
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You're fine.
The rear plug will always be a bit darker than the front.

What's up with the dot on your thumb??
Is it so that you know that's your left hand????
 
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Old May 17, 2019 | 12:32 PM
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Originally Posted by texashillcountry
You're fine.
The rear plug will always be a bit darker than the front.

What's up with the dot on your thumb??
Is it so that you know that's your left hand????
Ok thanks for the reassurance!

The spot on my thumb is a hammer bullseye. Works like a charm i seem to never miss!
 
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Old May 17, 2019 | 01:31 PM
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Originally Posted by Farm Shop
Ok thanks for the reassurance!

The spot on my thumb is a hammer bulls-eye. Works like a charm i seem to never miss!
Maybe put the dot on the nails you want to hit????
Just a thought...
 
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Old May 17, 2019 | 10:04 PM
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Originally Posted by Farm Shop
So i know this is about like starting an oil thread and i apologize..... I just wanted to get your opinion on my plugs. There is about 3k miles on these. Bike runs flawless no hesitation, or coughing, or breaking up of any sort. That being said they look just a tad lean to me but i want a second opinion.

Bike is an 86 heritage. Full s&s carb and air cleaner 295 intermediate and 70 main jet. 2 into 1 pro pipe.

Motor has 10:1 pistons in it with a 561 s&s cam. Running the ultima/dynatek ignition setup.

Plug on the right is front hole. Looks perfect to me. Left is rear. Looks a touch lean maybe??

Rear does look lean. Check for intake leaks.
 
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Old May 18, 2019 | 05:15 AM
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Left(rear) plug does appear to be lean on fuel compared to right(front) plug.
 
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Old May 19, 2019 | 07:33 AM
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Originally Posted by Son of PMS
Rear does look lean. Check for intake leaks.
I will triple check but intake seals were new at the time of rebuild about 3k ago. And before that the plugs always looked just like this with the rear one always being more white than the front.

I guess I can always bump my main jet up one and see what happens.
 
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Old May 19, 2019 | 08:53 PM
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Bumped my main up to a 72 from a 70. One quick beat run around the block and i like the results. Its hard to see becasue of the stupid camera flash but the rear plug now has a light grey/tan tint to it. And the front is a little darker as well

Still doesn't explain why they are so different though? No symptems of a vacuum leak or anything like that. Bike idles great, never pops or sneezes and pulls hard. Maybe something to do with my intake and or exhaust setup?

First pic is front hole.



 
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Old May 19, 2019 | 11:04 PM
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Plugs look ok. I always have different looking ones too. Rear does seem lean. If there is no pinging or if you can use a borescope and look at the pistons to be sure there is no damage, I wouldn't worry.
On a side note, I dont reinstall plugs once I pull for inspections. Personal choice but new plug always goes back in. It will always give the most accurate reading then.
 
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Old May 20, 2019 | 07:44 AM
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Looks great but the thumb is way too rich.
 
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