I was changing the spark plug out in my 03 rubicon which has about 400 hrs on it and when i took the spark plug out i looked down in the cylinder and the top of the the piston looked black and i mean solid black... i beleive its carbon build up.... my question is, is that normal for a machine with 400hrs on it, or is it because the machine is running too rich.... the spark plug hasnt been changed in a while and it was really black on the end... i know the ideal color is golden brown so not sure about that.......

Also i know honda is very reliable so is 400hrs alot of wear on the atv or does it have quite a long life ahead of it....

 

I've seen them with well over 2,000 hours, still running perfectly with nothing more than routine service type items.

A bit of black carbon wouldn't cause me any concern, if the machine runs fine otherwise. Has it been fouling plugs, burning oil, or smoking?

 

thanks for the reply.. no its not been smoking or anything like that at all.. no fouling plugs or anything... i was just wondering...

 

like JeffinTD said thats normal. actually carbon on the top of the piston is a good thing. that carbon coateing actually displaces alot of heat from the top of this piston. as long as its not smoking or using any oil ect. your mechine will be fine!

400 houres isnt anything for a mechine these days, i wouldnt get nervous until it hits 1,000 hours

 

awesome thats great.... thanks so much for the info

 

Pick up a can of Sea Foam at your local Auto Parts Store or a local Walmart Super Center and mix some up with your gas , run a tank of mixed fuel through the engine it will clean and burn off the carbon from the combustion chamber ; and it will also clean the entire fuel system this is a very good product you can get a 16oz. can that treats up to 25 gallons of gas or diesel fuel !

Works well with both 2 and 4 stroke engines i highly reccomend this product , it will more life to your engine and the cost is around $6.00 to $7.00 for for the 16oz. can ; complete mixing instructions for mixing on the can and has been around since 1942 with the same Guarantee " Your Moneys Worth Or Your Money Back" not many products on the market that has this Guarantee and i know it works !

I use it in every other tank full in my 2006 AC 400 FIS Auto 4x4 , so if isn't a carb jetting problem this will do the job ; and welcome to the forums !......

 

i agree, using seafoam will clean up any overly gunky carbon deposits. it wont take off a light coat of carbon, which is good for your engine to have. but heavy deposits of carbon are bad and can scar the cylinder, valves, and rings; and shorten engine life.

 

If the plug and piston dome was "really" black, I would lean it up a bit. There is zero reason to run an engine this rich. It will also solve a lot of problems.