Carbon streaks on cylinder?

[Mycamaro_68]

I need some help please. I have a Jonsered 2083 that I am getting ready to sell and while taking pictures of the piston and cylinder, it looks like scoring on the intake side of the cylinder. The piston looks great on the exhaust side. I used a small screw driver to see if I could feel the "scoring" but it felt smooth as could be. It feels like it has great compression. Is this what people refer to as "Carbon Streaking"?

 

[andyshine77]

Cameras and flash can make things look bad when that are not. It could just be some rubbing and maybe oil. Carbon scoring normally happens near the exhaust port, not intake, that would normally be debris ingestion. I would probably pop the cylinder off and have a closer look, it's super easy to do on these saws, you can even leave the carb and exhaust on the cylinder if you want. It does look pretty dry, not much residual oil that I can see. Maybe running lean, or 50:1?

 

[Mycamaro_68]

I mix my fuel at 40:1. This saw has been sitting for about a year. I will try and make some time this week to pop the cylinder off. I was super bummed when I saw this. Hopefully its nothing major.

 

[Moparmyway]

Looks like the exhaust port had some work done to it, no ?


Reminds me of the cylinders I’ve seen before that got the jms treatment

 

[Wolverine]

I bought a 357 a few years ago to flip. It had a ridiculously damaged chain on it. When I pulled the muffin, I found carbon scoring. I was worried enough about the resale that I put a fresh Meteor in it. Probably could have buffed the original and been fine. I'd definitely open it up if I were you.

 

[rogue60]

That looks like it's been so close to seizing from lack of oil to me.
And someone has had a good old time with a grinder in the exhaust port I'd be pulling the jug off to see how bad the rest of it is.

 

[Mycamaro_68]

I thought the exhaust looked like someone had played around in there too. I got this saw in a trade deal with no real story of its history. Thanks for all the words of wisdom! Keep them coming!

 

[andyshine77]

You guys are right, I was just looking at the cylinder wall, someone definitely went at that saw with some type of grinder. If you had fuel mix right I'm wondering if somewon installed a nice air leak. Probably do a vac test before pulling it apart.

 

[Moparmyway]

That diagonal line looks like a mandrel with a cutter was used to cut squish. jms is famous for it, scratching cylinders on the way in & back out.

I see two major commonalities with your pictures and the crap work that stool-stained con artist did to the cylinders of the saws that passed through my barn.

My apologies for saying that, and this: I’d bet a case of beer thats a jms cylinder. Most of his exhaust port work was polished, but I’ve seen a few that weren’t, especially if he thought that he could get away with half assing it

I could be wrong, and I hope that I am, but I’d happily help you down a few cold ones from that case either way

 

[blsnelling]

That topend doesn't look good at all. Sorry.

 

[Al Smith]

What it could be is a portion of the plating on the exhaust port missing .Flaked off,ground off allowing aluminum to aluminum contact .--just a guess .It certainly would not help if that is the case to run a low oil ratio in the gasoline .

 

[MustangMike]

I had an 066 that has slight scoring on both sides of the piston, but the rings were free and it ran fine.

I ended up replacing the P+C, but likely did not have to, compression was good and I ran it for months that way.

I guessed it was just run too hot and almost seized.

Your damage on the intake side looks worse than what I was dealing with.

 

[Mycamaro_68]

My memory is horrible so I checked my old PMs from when I made the trade deal. The fella I got this saw from said he rebuilt it with oem bearings and seals and a golf brand piston. He had sent me a picture of the piston but not a picture of the bore. I didnt notice the port work at that time and he never mentioned it. This all went down over 3 years ago and I doubt that I ran a full tank of fuel through it in that time. He hasn't been active here for a while so its doubtful I will get any other info from him.

I will make some time in the next week or so to pop the top off and get a better look.

I'm just happy I caught this before I tried to sell it though!

 

[Cut4fun]

Pull the topend. I have only seen 1 other 54mm with 2 ring piston oem. Most with 2 ring have had the 660 piston put in. I have done that.

Dont know if pic shows stock look on the 505. Sorry nope. Here a fubbared 2083 of mine I found.

But that cyl IMO is crap had a 2083 come in like that with crap porting. I tried my best to clean this 2083 cyl back up and then the fing crank broke.

Toss that golf piston and grab a meteor 66. If you can get the cyl cleaned up.

 

[Moparmyway]

The fella I got this saw from said he rebuilt it with oem bearings and seals and a golf brand piston. He had sent me a picture of the piston but not a picture of the bore. I didnt notice the port work at that time

wanna guess jms’s favorite AM piston to use ?

 

[Nutball]

That diagonal line looks like a mandrel with a cutter was used to cut squish.

The OP mentioned running a screw driver along there to try to feel for scoring. I assumed it was a mark from that.

 

[blsnelling]

I believe that topend had a seized piston in it before and was cleaned up. There was still damage and that's what tore up the new piston.

Golf pistons are bottom of the heap.

 

[MustangMike]

Maybe the new piston is not torn up, maybe they just never properly cleaned the cylinder, and it needs to be cleaned and the piston is new and undamaged (but I would not leave a golf in there).

The more I think about it, it looks like it was just a quick fix, with a new piston for show but never doing the work to clean up the cylinder.

 

[jacob j.]

I thought the exhaust looked like someone had played around in there too. I got this saw in a trade deal with no real story of its history. Thanks for all the words of wisdom! Keep them coming!

Did you make the deal here, another forum, or on Facebook? I would definitely pull the jug and get the full story on it. Like Kevin said, a Meteor 066 piston
is a good replacement for the OEM piston.

 

[Mycamaro_68]

Did you make the deal here, another forum, or on Facebook? I would definitely pull the jug and get the full story on it. Like Kevin said, a Meteor 066 piston
is a good replacement for the OEM piston.

It was a deal through here.

Edited to add: It was over 3 years ago... Back when I really didn't know what to watch out for. Every day has new learning opportunities.