How is my piston?

GLantern

GLantern

New member
I'm going through my gasser (2012 EC300) piece by piece to get it ready for next season. I took a peek inside the exhaust port last night and took some pics of the piston and cylinder. I'm not very familiar with how everything should look and what is ok so I figured I would ask you all on here about it. From what I have read it looks like I'm getting some blow by. The piston feels smooth to the touch on the exhaust port side.

Piston
207463ffdd2210f2c893d43c21447c02.jpg

2cd01cff967c921a24f1b8b0c17aba0a.jpg


Is that scoring?
Cylinder
11952d9495bbc59464cd74462f47437a.jpg


I don't know how many hours are on the piston as I bought the bike used. I put about 30 on it since I got it. I should also add the bike has been running fine as far as I can tell, I rode it 3 weeks ago.

Thanks for any advice on next steps here, new piston, new rings, new whatever else?


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Last edited:
GLantern said:
I'm going through my gasser (2012 EC300) piece by piece to get it ready for next season. I took a peek inside the exhaust port last night and took some pics of the piston and cylinder. I'm not very familiar with how everything should look and what is ok so I figured I would ask you all on here about it. From what I have read it looks like I'm getting some blow by. The piston feels smooth to the touch on the exhaust port side.

Piston
207463ffdd2210f2c893d43c21447c02.jpg

2cd01cff967c921a24f1b8b0c17aba0a.jpg


Is that scoring?
Cylinder
11952d9495bbc59464cd74462f47437a.jpg


I don't know how many hours are on the piston as I bought the bike used. I put about 30 on it since I got it. I should also add the bike has been running fine as far as I can tell, I rode it 3 weeks ago.

Thanks for any advice on next steps here, new piston, new rings, new whatever else?


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Click to expand...


Besides that "red stuff" on the piston which looks like "rust" but I doudt it is, and exhaust power valve looks pretty clean.

What your seeing in the cylinder is the "cross hatch" and that looks pretty darn good = very little wear!

If it was mine I'd ride it! Pull a compression test and go from there! Some of these guys are getting a ton of hours out of a 300 topend, I think 70-100 + hours on a rec rider topend is pretty good, some more get more hours depending on how the bike has been cared for.
 
I can only think that red stuff is some metal element contained in your 2 stroke oil that acts as a lubricant? Never seen anything that looks like that before!

Cylinder looks new!
 
Agree with all above. Everything looks good, with exception to the odd red coating which I imagine would be oil related based what else can be seen. What brand oil?
 
I'd definitely look at a oil with a higher flashpoint, and perhaps slightly richer jetting. It doesn't look like there is any blow by on your rings (from excessive wear) but due to the way a 2 stroke works those red but a will get sucked back in to the bore and between the piston and bore, or worse into the crank bearings.

Do you know your jetting?
What oil ratio are you using?
Does the bike ever run hit at all?

When I look at my piston through the bore it is wet with 2 stroke (a good thing), that looks dryto me.
 
I never touched the jetting on the bike, it ran pretty well except in the cold down low. I just picked up a jd jet kit for a Christmas gift and will be installing that before I take the bike out next.

My ratio is 50 to 1.

As for running hot I never had the bike boil over but the last time I rode it I felt the temperature read out was hovering a bit higher then normal.



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You will like the Interceptor, ive been using it for years.

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I have always been an amsoil fan I'm not sure why I hadn't switched sooner. I'm glad to hear someone else has a good experience with it.


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ive put 50hrs from new running belray h1r and my piston/ports do not look like that.no red residue and everything is oily,in fact the entire inside of pipe from piston to muffler tip is oily!h1r has one of the highest flashpoints,ie it doesn't burn easily!im running 40:1 as per packet recommendations.id say if that's oil residue its from the previous owner and whatever oil they used not h1r unless youre running a lot hotter/leaner than me.what does your plug look like?what is your local fuel grade/octane/ethanol?not running well in the cold may suggest lean mixture.can you get a pic of the piston dome,with piston fully down?
 
I'll check my plug later but my fuel is 91-93 octane and 10% ethanol. Maybe it is from the previous owner then.


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Nothing that loose would be from the previous owner, and the fact it is dry raises concerns to me. Forgive me if I'm wrong, but I love 2 stroke and have ape t a fair amount of time reading up on them and working on them, that looks hot to me, and I'd imagine any sustained full throttle bursts could cause severe damage. Do some plug chops and get it perfect imho
 
K I will, I'm going to get the jetting sorted out over the next couple of weeks. Excuse my ignorance, what's a plug chop?


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throw a pic of your current plug up first,it might tell us more.a plug chop is used to check the jetting at certain throttle positions.eg.you go flat out for a few hundred yards,kill the engine and coast to a stop,pull the plug to see how your jetting is.can be done at different throttle settings.BUT if your too lean I wouldn't be doin full throttle plug chops just yet.the plug you have in should tell us something as is,so start there.personally I find it difficult to read new plugs with only a few minutes running,i wait until I have a few hours on plug avoiding long wide open throttle,then check plug,then when youre pretty sure its close,do a wide open plug chop,with a new or slightly used plug.different parts of the plug can tell you different things about the mixture at idle,part,and wide open throttle.google 2 stroke spark plug reading and compare your plug,or post a pic.plenty of helpful people on this forum will give you pointers for your jetting.however I personally have no exp with ethanol fuels and their effect on jetting so hopefully someone more knowledgeable will chime in with information more specific to you.include the altitude you ride at,and the temperature range,along with your fuel blend and oil ratio to get more specific jetting info.or scroll through the jetting database and see if you can find an equivalent setup to yours
 
1 - remove your spark plug, take a picture and post it here, it will tell us a lot.

2 - fit a new plug, warm the bike up normally, ride it until hot, then gas through all the gears at full throttle on a nice straight bit of land, try and maintain full throttle as long as possible then hit the kill switch, pull the clutch in and let it die.

Remove the plug, take a picture and post it here. The plug should be a nice medium light chocolate / tan colour.

3 - do the same as above but at half throttle to 3/4, this will tell you how your needle is jetted.

4 - do the same again, but warm it up, then just let it idle for a minute and remove the plug.

If you are anything like most of us, you spend most of your riding on the needle (mid throttle) with few full throttle bursts.

If at any time you find a light, burnt, yellow / red / light brown colour, it almost always indicates a lean condition, just as the darker the colour, the more rich (safer)


Just to add, this isn't a gas gas only problem, all bikes are given a "general" jetting and it is up to the owner to tune it in. It is far more obvious on 2 strokes as 1 jet can make a huge difference, the equivalent change in a 4 stroke can be up to 3 jets!
 
That thing has been HOT! Given that you are running 50:1 and your jetting is too lean you have a ticking time bomb. You need more fuel!!!! The brown/red stuff you are seeing is soot from your oil being burnt at a really high temp. Pull your plug out as it sits and let us have a look at it.


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Here is my plug
203cd9edab7df2af7a7ea7bb80d8908a.jpg
294392231a9a938c1d2645be63c26ea9.jpg
81535a923b38962de9adb8dccf74f890.jpg


I think it looks pretty good? It has that chocolate tan color, maybe I wasn't lean. Let me know your feedback.

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Dark outer ring indicates lean idle which is good. Centre electrode looks like its been a bit hot to me. You need to find out if its the main jet or needle (or both) that's running lean. I would def go up 2 sizes on the main before doing a proper plug chop as a precaution.

It still gets me that your piston looks so dry also, consider running more oil in your mix (then rejet).
 
Thanks Moto I'll do that. So I'll switch to a bit more oil in my mix, 45:1 or 40:1, what do you suggest? Then go up 2 sizes on the main and see how it all looks, I'm glad I got that kit for Christmas! Then plug chop!

Might be a little bit as I have the bike in pieces right now but I'll be sure to follow up as soon as I do.


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