What Do My Plugs Say?
Joined: Dec 2001
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From: NY, MA, MI, OR, TX, and now LA or AZ!
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.
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.
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.
example, my plugs look fine even though it has a bad coolant seal at the rear housing.
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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
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.
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.
its good to konw they look ok, but ive never seen the brown/tan stuff on them before and was a little worried.
What brand premix?
At what ratio?
The plugs look "oily".
Weird.
-Ted
Locust of the apocalypse
Joined: Apr 2003
Posts: 2,553
Likes: 2
From: Directly above the center of the earth (York, PA)
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.
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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