Who's running scored pistons in their saws?

[August76]

Makita mistake buy $140 it's a ea6100p. Wasn't able to remove muffler in Walmart parking lot so I took gamble .got home found this. Does run.
Seemed to bogg cutting more like carb issues. Dunno what to do with it now.
Bucking wood with my dolmar 111 now. But need bigger for all this dead n down and forest service trim firewood I'm grabbing for winter selling.
Any idea why this got scored?

 

[pioneerguy600]

Looks like a bad case of carbon scoring or a foreign object got sucked in the exhaust. Piston looks fine otherwise in that there has been good fuel oil mix run most of its time til this scoring happened.

 

[Cantdog]

I would guess....not that good of an oil and to much of it......heavy, gooey carbon deposits in the ex port tells the tale. As Jerry suggested I suspect that some of the carbon build up broke off and got stuck between the piston crown and cyl wall giving you those streaks. I would take it apart, clean the cyl and port up real nice, getting rid of all that carbon. Clean the piston gently with scotchbrite or similar.....the ring may be fine but I almost always replace it....they're cheap and you're already there...put it back together and enjoy it. Might want to put a new kit in the carb too and check the fuel line for any issues while you have that stuff apart too. I think there's a lot of hours still left in that rig basically as is......minus the carbon.

 

[kz1000]

Been looking at all those pistons and cylinders, now I think I may have got screwed! I thought all them grooves was "finger ports" and payed extra for a properly "woods ported" saw.

 

[August76]

Looks like a bad case of carbon scoring or a foreign object got sucked in the exhaust. Piston looks fine otherwise in that there has been good fuel oil mix run most of its time til this scoring happened.

Kinda what I figured. Auto mechanic here. I've seen it happen on a motor from seafoam loosening up carbon on a neglect motor.
Wonder can I just run this thing?

 

[August76]

I would guess....not that good of an oil and to much of it......heavy, gooey carbon deposits in the ex port tells the tale. As Jerry suggested I suspect that some of the carbon build up broke off and got stuck between the piston crown and cyl wall giving you those streaks. I would take it apart, clean the cyl and port up real nice, getting rid of all that carbon. Clean the piston gently with scotchbrite or similar.....the ring may be fine but I almost always replace it....they're cheap and you're already there...put it back together and enjoy it. Might want to put a new kit in the carb too and check the fuel line for any issues while you have that stuff apart too. I think there's a lot of hours still left in that rig basically as is......minus the carbon.

I started to tear the saw down when I realized that you had to remove all of the crankcase and everything to get The Jug off so I put it back together but the saw is actually from 2016 so it's not that old where would be the best place to order a piston ring I poked around on the internet and apparently as luck would have it I happen to buy the one dolmar Makita that you can't buy a Big Bore Kit for it looks like

 

[Cantdog]

Ahhh.....it's a clamshell then...you do have to take them all apart to get the jug off but once you have the flywheel, clutch and oil pump off they are real easy to work on. Most usually have a couple gaskets and crank seals that you will need to acquire too but not to bad really as long as you take it far enough apart. Some folks get angry that they have to perhaps do this much work on a new to them saw.......I kinda look at it from the other end.....parts to go through this little saw might cost an additional $25.00 or so.....plus a little time but when you're done you'll have an as new saw that you know every thing about.....no worries or trying to figure out what someone else has done.

 

[August76]

Ahhh.....it's a clamshell then...you do have to take them all apart to get the jug off but once you have the flywheel, clutch and oil pump off they are real easy to work on. Most usually have a couple gaskets and crank seals that you will need to acquire too but not to bad really as long as you take it far enough apart. Some folks get angry that they have to perhaps do this much work on a new to them saw.......I kinda look at it from the other end.....parts to go through this little saw might cost an additional $25.00 or so.....plus a little time but when you're done you'll have an as new saw that you know every thing about.....no worries or trying to figure out what someone else has done.

so is it really worth fixing this particular saw.
I need a 60+ cc saw to power through bs and get done quicker. My 52cc dolmar 111 works great when it runs mostly but once the temp gets into 90s the saw is very hard to re start if you shut it off.
So basically looking at that picture The Jug should be okay or am I probably looking at needing a new jug piston and ring because I priced it out and the cheapest I could find was $128 and I don't want to put that much more money into this saw I'd rather go spend $320 on the 64cc saw that they have at Home Depot for sale as a former rental also at least those you can do the big bore on

 

[Huskybill]

Older new parts I’m not sure to stock up on pistons, cylinders and bottom end parts.
I have enough new parts for my husky dirtbikes to support a post vintage race team.

 

[August76]

Older new parts I’m not sure to stock up on pistons, cylinders and bottom end parts.
I have enough new parts for my husky dirtbikes to support a post vintage race team.

I used to do that with cars and all my old tube hybrid ham radio stuff.. certain stuff is just hard to find or when you want it. it's expensive, and when you don't need it it's dirt cheap... there in lies the creation of hoarding

 

[Cantdog]

so is it really worth fixing this particular saw.
I need a 60+ cc saw to power through bs and get done quicker. My 52cc dolmar 111 works great when it runs mostly but once the temp gets into 90s the saw is very hard to re start if you shut it off.
So basically looking at that picture The Jug should be okay or am I probably looking at needing a new jug piston and ring because I priced it out and the cheapest I could find was $128 and I don't want to put that much more money into this saw I'd rather go spend $320 on the 64cc saw that they have at Home Depot for sale as a former rental also at least those you can do the big bore on

I am not at all familiar with the Makita chainsaws so I can't really comment on worth but you're already into it for $140.00. I've studied your first three pics by right clicking on them and opening a new window then left clicking on the pic when it comes up....this really zooms in close for a good look. I don't think it looks bad at all nor do I think you need either a piston or cyl but I would want to get that crappy carbon out of the port and by the looks of your plug probably should clean the combustion chamber as well. Carbon in any form is the killer of two strokes. Myself, after a through cleaning I'd install a new ring and what ever pertinent gaskets and seals....like I said probably another $25-$30 bux. If you know the bore and the thickness of the ring Northwoods Saw is a good place to look up a Cabor ring.....may be sold as fitting a Stihl or Husky but as long as you get the correct diameter and thicknesss you'll be fine...just be sure to check the end gap midway in the cly...should be .006-.008 of so,

 

[August76]

I am not at all familiar with the Makita chainsaws so I can't really comment on worth but you're already into it for $140.00. I've studied your first three pics by right clicking on them and opening a new window then left clicking on the pic when it comes up....this really zooms in close for a good look. I don't think it looks bad at all nor do I think you need either a piston or cyl but I would want to get that crappy carbon out of the port and by the looks of your plug probably should clean the combustion chamber as well. Carbon in any form is the killer of two strokes. Myself, after a through cleaning I'd install a new ring and what ever pertinent gaskets and seals....like I said probably another $25-$30 bux. If you know the bore and the thickness of the ring Northwoods Saw is a good place to look up a Cabor ring.....may be sold as fitting a Stihl or Husky but as long as you get the correct diameter and thicknesss you'll be fine...just be sure to check the end gap midway in the cly...should be .006-.008 of so,

Ok. Yeah I figured if it was bad bad it wouldn't run well. I've rebuilt several motors in cars . I'll try to source a OEM makita dolmar ring

 

[pioneerguy600]

Stay away from the big bore kits if at all possible, they are mostly a cheap alternative to OEM and for the most part never work as good as original parts. I have owned and worked with many Sachs Dolmar and Dolmar saws,they were the forerunner of Makita saws. I havn`t worked on a clamshell Makita but I would if one came my way, these saws were always well built and worth repairing. My first SD saw was from 1985, a 116 & 120S , they still run as good today with just a little maintenance they will outlast me.

 

[August76]

Stay away from the big bore kits if at all possible, they are mostly a cheap alternative to OEM and for the most part never work as good as original parts. I have owned and worked with many Sachs Dolmar and Dolmar saws,they were the forerunner of Makita saws. I havn`t worked on a clamshell Makita but I would if one came my way, these saws were always well built and worth repairing. My first SD saw was from 1985, a 116 & 120S , they still run as good today with just a little maintenance they will outlast me.

I have a dolmar 111 the makita ea6100p and I picked up a makita dcs6421 last night . I need to order a piston ring for the ea6100p so I can fix it. It's a pretty light saw and I really want to use it. I just hope the cylinder is ok

 

[pioneerguy600]

I have a dolmar 111 the makita ea6100p and I picked up a makita dcs6421 last night . I need to order a piston ring for the ea6100p so I can fix it. It's a pretty light saw and I really want to use it. I just hope the cylinder is ok

They are good saws and will give long service if looked after. Congrats.

 

[chunez]

Think this will clean up? Rings are free. I’m happy to spend $100 on a new OE 390xp piston too, just not sure how far gone this one is

 

[Cantdog]

I'd say that's toast........I mean it could be cleaned up and with a new set of rings could be made to run again. To bad too....that piston was in good condition wear wise before this happened. I'd put a new OEM piston in it myself if money is no problem but more importantly you need to find out why this happened and correct the issue before installing a new piston as it will very likely happen again to the new piston if not cured.

 

[huskihl]

Think this will clean up? Rings are free. I’m happy to spend $100 on a new OE 390xp piston too, just not sure how far gone this one is

That looks like it was straight gassed. Get a new meteor piston and rings to put in it. Make sure you clean any scoring out of the OEM original cylinder

 

[Cliff R]

One of my Husqvarna 55 closed port saws was purchased off Ebay and had HEAVY piston damage and some transfer to the jug. The ring was seized solid in the piston.

It cleaned up nicely and has been in service over 20 years now without issue. The key to success here is that you can remove the transfer, free up the ring, and that the damage doesn't extend into the cylinder wall leaving deep heavy gouges in it. Provided the piston still holds the ring nicely, and the piston skirt still tight in the bore, and you get all the transfer off the cylinder, it's going to be fine. Back when I saved the 55 CP there was only a couple of OEM P/C's still out there and the folks selling them wanted over $300 for them. Otherwise I would have just replaced all of it and moved on.

The 55 runs equally as good as the other CP 55 that I have in the line-up and was up near 160psi cranking pressure last time I checked it.

I'm really not recommending that others do the same thing as your results may vary.

I'd add here that I've worked on small power equipment for over 45 years, 20 of it full time till retiring 3 years ago and closing down that part of the business. I never spent that sort of time on a customers saw as I'm not willing to send anything out the door that isn't repaired correctly with the best possible parts available. I will NOT use aftermarket P/C's for any reason. It's OEM or we simply handed the saw back to the owner and told them to get another one.....FWIW......

 

[Bob Hedgecutter]

In some of my own personal not for sale saws- yes certainly some are running pistons with scoring- especially if they belonged to someone else first and I got them at my regular bargain basement price!

Better question: How many folk are running a scored piston and have know idea it is?

If the World was full of folk like us that like to pull things apart and fix them- all the saw service shops would be closed!