2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

What Do My Plugs Say?

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Old Feb 3, 2005 | 04:51 PM
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What Do My Plugs Say?




other than the oviously rich, what its the brown stuff on them?
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Old Feb 3, 2005 | 04:58 PM
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Almost looks like a little rust, usually caused by bad coolant seals, but if it comes off fairly easily it could just be ash, as sometimes it'll be brown colored like that.
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Old Feb 3, 2005 | 05:03 PM
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yup don't look too bad to me
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Old Feb 3, 2005 | 05:06 PM
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Originally Posted by SonicRaT
Almost looks like a little rust, usually caused by bad coolant seals, but if it comes off fairly easily it could just be ash, as sometimes it'll be brown colored like that.

It better not be bad coolant seals, motor has only 3k miles on it.
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Old Feb 3, 2005 | 05:14 PM
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they look ok.
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Old Feb 3, 2005 | 05:24 PM
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it's hard to tell what shape a rotary engine is in by how the plugs look, unless they are coated in oil or rusted solid or coated with coolant they "seem" to be ok, but even a firing plug can fire itself clean enough to mask some of major conditions with an engine.


example, my plugs look fine even though it has a bad coolant seal at the rear housing.
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Old Feb 3, 2005 | 05:35 PM
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They look fine.
They tell me you're still using the stock oil injection system.

The tan colored deposits are from gasoline additives.
It is completely normal.


-Ted
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Old Feb 3, 2005 | 06:19 PM
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Originally Posted by RETed
They look fine.
They tell me you're still using the stock oil injection system.

The tan colored deposits are from gasoline additives.
It is completely normal.


-Ted

im premixing......

its good to konw they look ok, but ive never seen the brown/tan stuff on them before and was a little worried.
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Old Feb 3, 2005 | 07:40 PM
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They say ...you like Mt DEW
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Old Feb 3, 2005 | 08:58 PM
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Originally Posted by zooooom
They say ...you like Mt DEW

like isnt the word, its more like an addiction
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Old Feb 3, 2005 | 09:48 PM
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If anything, the second set look a little rich...the brown coloration is fine, seems to be buring ok. Electrodes look fine too...check again at your next oil change.
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Old Feb 4, 2005 | 05:23 AM
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Originally Posted by gergrx7
im premixing......

its good to konw they look ok, but ive never seen the brown/tan stuff on them before and was a little worried.
Interesting...
What brand premix?
At what ratio?

The plugs look "oily".
Weird.


-Ted
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Old Feb 4, 2005 | 08:37 AM
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You're probably mixing in too much...don't wanna clog that fuel filter!
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Old Feb 4, 2005 | 10:39 AM
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From: Gainesville, FL
Originally Posted by RETed
Interesting...
What brand premix?
At what ratio?

The plugs look "oily".
Weird.


-Ted

i use chevron 2 cycle oil at 1oz:1gallon
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Old Feb 4, 2005 | 11:17 AM
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there ya go..... chevron oil..... switch over to quicksilver tcw3 at 1oz per gallong and you'r plugs should look better....

NOW THEN......... when looking at plugs..... what you look at is the ceramic ring around the center electrode, thats the part that will tell you the most about whats going on in the combustion chamber.... that part of the plug looks normal... Coffe with lots of cream colored deposits on the plugs is good.... on a two stoke motorcycle....... being that the rotary is similar, especially when premixing, it follows that the plugs would look similar... being that my plugs always look pretty close to my RD350's (street bike with a Banshe twin cylinder two-stroke in it) plugs in color and condition, i'd say there is some creedence to it. When i had the car running dog rich before i got the haltech tuned in... the plugs looks exacly the same as the RD350's plugs when i had too big of main jets in the carbs.

The metal slots around the edge of the plug always have some carbon on them.. but you should be concerned if the metal pads have hard nubbly bubbly crusty glassy looking deposits on them... signs of running hot (I've seen this several times on cars that were running lean on one rotor because of bad injectors) From the pics.... its hard to see, but i don't think your plugs show any real problems.

HOWEVER........ This is all voodoo science..... an EGT gauge and a wideband are the best ways to tell for sure whats going on inside the motor, but the plugs can give you an indication. Don't ever let anyone tell you that they know EXACTLY what your problem is by looking at your spark plugs.... they are an indicator of a symptom, thats all.
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