How long has the plug been in the ATV? How many miles? Any problems with the ATV?

 

cant really go by a plug thats been in there for a long lime, put a new one in and run it a few hours in normal conditions. you have a k and n?

seems almost like the one a worked on for a guy in my club, was a newer 450 wolvy, had oil leak and was getting on the plug, the k and n filters let the dirt right by and ruins the rings and jugs. you get oil blowby and blackish build up on the plugs. but that is worst case really

 

If you short them up cold and then shut them off in 30 seconds often, any machine will foul plugs shortly. If its had short runs, its completely normal.

 

don't really look that bad to me. i have always thought that a brownish color was a good clean burn. i have had them come out oiled or wet from gas, more on the 2 strokes than the 4 strokes. i wouldn't be too concerned over your plug but that's just my opinion.
brown --good
black-- too rich
white---too hot

 

Those plugs show a healthy engine. IMO that is.;-) Brownish red is from today's fuel additives I've been told.

 

A good running 4 stroke won't hardly color up the plugs. Pull the plugs from a modern car, and they come out nearly white. They look scary almost, but a 4 stroke isn't supposed to color up the plug like a 2 stroke does. The cardboard brown color is for 2 strokes.

Fuel additives do add a huge amount of color and deposits on the plugs, differing of course by region depending on the fuel we all have available.

 

Just got the bike last summer and personally I've put about 75 miles on it so far. Not sure how new the plugs are but the machines got only about 800 total miles.

Sounds like I'm relatively ok with this coloration then. I'll take that advice and leave everything alone

 

plug is likely original would change the plug and look again after a ride or two, only takes a few minutes.

 

A good running 4 stroke won't hardly color up the plugs......really??? hardly any color??
well i guess that all my 3 wheelers and 4 wheelers , motorcycles all through the years were not running good because they all had a nice brownish plug which i thought was a good clean running motor. just pulled a plug on my honda vtx 1300 not to long ago and it was nice and brownish...it runs superb

 

Pull the plugs out of a modern car, and look for yourself if you don't believe me!

 

the blackish stuff is the concern. could be oil

 

LOL....how can you even compare an atv with a car?? cars will be different because they are better managed electronically. a cars computer is way more sophisticated than an atv engine management system. thus a cleaner spark plug,, but a brownish color 4 stroke atv/motorcycle sparkplug is by no means a bad sign.

 

EXACTLY my point. :clap smilie:
The car spark plugs are spot on and they are white, so thats HOW a perfectly running 4 stroke SHOULD run.
You said you want brown spark plugs, so maybe you belong on a 2 stroke.

 

I always thought that oil on the plugs isn't good, regardless of the engine?...like that shows a leaking head gasket

 

Ok so I'm potentially looking at a leaky head gasket, lovely. How do I go about further testing this?

 

your engine is fine...throw a new plug in it and let er rip.

 

not gonna get white plugs on an atv/motorcycle like a car. that's the point im saying...

 

Ok the brown on the plug is a very good sign, Automotive or powersport it doesnt matter but the blackish oily part looks like your burning some oil. Its either from oil ring or valve guides. Change your oil & plugs see what happens if its burning oil you will know bluish smoke. It really doesnt look that bad i wouldnt be worried about it personally run it see how long before you foul the new plug that will be your answer.

 

Thanks rockcrusher. I'll be changing both the oil and plug this week and then be following your advice to see how long the plug takes to foul again.

Anybody else have an opinion on further diagnosing a plug w/ possible oil deposits on it?

 

if its getting oil in the engine not much you can do but take the engine apart and check things out as per the manual measurements for the jugs and inspect the valve seals. you might luck out if that is the case, the wolvy i worked on had room to get the jug bolts off on the machine. the kawis and stuff anything in the engine or trans is engine out on the bench