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First piston change. Newbie questions.

Discussion in 'Chainsaw' started by Ryan_289, May 10, 2019.

  1. Ryan_289

    Ryan_289 ArboristSite Member

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    I pulled the cylinder on my Husqvarna 61 project tonight. For showing 150 psi on my gauge, the piston had quite a bit of wear. I was looking at the meteor pistons and the windowed piston they show does not have the ring around the bottom like mine does. Will it still work fine? I did find an oem piston for about $75 if that's a better option. My other question is on honing the cylinder. This on is pretty smooth but I dont see how a hone will work with the open ports. Do you do it by hand and if so how?[​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]

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  2. huskihl

    huskihl Addicted to ArboristSite

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    It'll run fine with the windowed meteor.
    Maybe better yet with the non windowed meteor
     
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  3. Backyard Lumberjack

    Backyard Lumberjack Tree Freak

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    if that was my saw... and it ran fine with 150 psi, I would clean the bore, clean the piston and re-ring it with a good set of new factory rings.

    if that was my saw... I would forget the word hone. I would think deglaze the bore. it will upset it enuff to seat the rings. and I would take some 600 grit wet/dry sandpaper... must be wet/dry (the gray stuff) and fold it into quarters, wet the bore and the 600 grit with gasoline... put the wetted 600 grit into the bore and rotate around the bore perpendicular to the piston stroke. I would not go up and down. I would do this briefly just so as to break and deglaze the bore. then clean well. keep all debris out of crankcase!! on some of my past engines, 2 stroke and 4 stroke this procedure has deglazed the bores sufficiently to reset the rings and let them seat while not removing excessive bore material such as on a well used or worn bore, which is very easy to do if power honed. for small areas of bore I would use smaller piece of the wetted 600 and do the same direction. you may get many ideas on honing, replacing etc... but I am one who has... not wanting to pull an engine but wanting to freshen it up... done rings like this and done rods and mains with not new bearings... but using brass shims. with valve job, etc got another 75,000 miles out of it. but of course, with this level of DIY, one has to know what they are doing. and how to read a bearing. but u have the piston out, so u must have some experience. a thinner cyl to crankcase gasket may help, too.

    your piston's oil grooves are all but non existent. these are important items on the piston to help ensure proper lubrication of the piston to bore when saw running. if it was my saw, it would depend on how I intended to use it, assuming I intended to keep it. I might just up the oil mix in the fuel by 10%, rings and deglaze the bore. a fresh bore, new set of rings and a new piston will give you the best combination. short of that new rings and a hone will do wonders. if it seizes or galls... well, there are ways to remove the alum from the bore. and u will need a new piston. maybe now is the time for a new piston. no doubt a good used serviceable OEM piston will be a good choice if u don't choose to buy a new one or an aftermarket piston.

    good luck with your saw project!
     
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  4. drf255

    drf255 BAD CAD

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    The light area under the intake port looks like worn off plating to me. That’s where it typically occurs, as the intake wall is where the thrust occurs.

    With the open transfer design, a 3 stone hone won’t work. Ball Hones are just bad, they will enter a port and tear off the plating on the side they rotate towards.

    Get the meteor piston.

    Use some muriatic acid on a Qtip, after degreasing that jug, and apply cautiously while using eye and skin protection. You’ll see what fizzes and what doesn’t. Have a bucket of hot water with baking soda dissolved in it to neutralize the acid. Be very careful by port edges and any areas that keep fizzing, you can undermine the plating and ruin the jug.

    When you have done above, use scotchbrite on a drill with some type of arbor and spray WD40 into jug. Hone it with that.

    If it’s a saw you will be keeping, I’d personally find a good used oem jug on the trading post here. That intake port is telling me that the jug has seen its use and performed it’s duty. Make sure your air filtration system is up to snuff as well.
     
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  5. Huskvarna hotellgäst

    Huskvarna hotellgäst ArboristSite Operative

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    You have been busy :)

    61s did not leave the factory with a "powerflow" piston, either windowed or partially skirted (which I guess is what the Hyway piston you've found is).

    1. Do the carb bolts go through the intake block and into the cylinder?
    2. Before you order, measure the bore. It should be 48mm. If that's the case, the piston you have is for a 162. A 162 piston will work but the open sides are not necessary.

    If the bore is larger than 48mm, e.g. 50mm, you have a big-bore open-port replacement cylinder (if in fact such a thing exists).
     
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  6. Ryan_289

    Ryan_289 ArboristSite Member

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    So on these little saws, a light glaze from fine grit sandpaper is the way to go? I've never rebuilt a small engine before, my only experience is on larger 4 cycle engines.

    I looked at that area last night. I will double check but it looked to me like it was original glazed cylinder there. Almost as if the rigs were not making contact on that spot and the rest of the cylinder was worn smooth by the rings. I will look again after I get home from work.


    1. Yes
    2. Will do, as far as I know this is the original cylinder and piston on this saw. My Grandfather bought it new in 86 model but I was born in 82 so I wouldnt remember the first few years of use. The Husqvarna piston I linked below factory number matches my year model and looks like mine.

    These are the 2 pistons im looking at.
    https://www.ebay.com/itm/Meteor-piston-kit-for-Husqvarna-61-Jonsered-625-630-48mm-Italy-windowed/181799366976?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

    https://www.ebay.com/itm/NEW-OEM-HUSQVARNA-PISTON-KIT-503517401-503-51-74-01-FITS-CHAINSAW-61-162/133005917995?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

    or there is a non windowed piston from Meteor as well. With an open port cylinder either will work correct?
    https://www.ebay.com/itm/Meteor-pis...052315&hash=item28035da278:g:KXAAAOSw9N1VoXAZ
     
  7. Ryan_289

    Ryan_289 ArboristSite Member

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    Im 2 stroke small engine dumb. Why would one work better than the other?
     
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  8. jltrent

    jltrent ArboristSite Operative

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    IF the piston skirt looks good and thick re-ring put back together and run. At 150 psi should have left it alone to start with. There is very little if any noticeable difference in 150 psi and 160 psi . On smaller saws you will notice it a little more.
     
  9. Ryan_289

    Ryan_289 ArboristSite Member

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    Last time I heard this saw run was in the early 2000s. Dad said it was running when the put it up but judging by the looks of the saw and the slickness of the piston from the muffler port, I wanted to have a look. Besides, ive never had a chainsaw cylinder off so I needed to check that off my list! I have 3 daughters and a wife so naturally I spend lots of time in my shop!
     
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  10. Huskvarna hotellgäst

    Huskvarna hotellgäst ArboristSite Operative

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    The cylinder could be the original but the piston is not. A 61 piston looks like the 3rd on your list, with a full skirt.
    The first one should work ok. It'll be lighter than the full skirt version. There's a very slight risk of cracking of the diagonal piece between the gudgeon pin and the skirt but probably not worth worrying about in a 61 which won't rev as high as a 162.
    The transfer ports in a 162 start and finish in the cylinder wall. Therefore the only way the fuel mixture can enter them is through the gap in the piston skirt. The 61 ports go straight down to the crankcase so there's no need for anything other than a fully skirted piston.

    Other thing to check is that the top of the cylinder doesn't have an 'A' stamped on it. The 1st meteor piston is a 'B' which is the most common grading and will be ok in either a 'B' or 'C' cylinder but might be a bit tight in an 'A'.
     
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  11. huskihl

    huskihl Addicted to ArboristSite

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    I thought meteor made a non windowed slab sided piston, rather than the full skirt piston in your 3rd option above. Typically, pistons with recessed sides like the windowed meteor will run a little better due to less drag and reduced weight.

    When I made my 1st post, only the first couple pics would load. Like Doc said, it looks like the plating is worn off on the intake side of the cylinder. And the piston shows coinciding wear. I'd bet the intake side of the piston skirt is worn thin as well. The cylinder may last awhile like that for home use, but if the piston skirt is thin I'd replace at least the piston.
     
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  12. Backyard Lumberjack

    Backyard Lumberjack Tree Freak

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    I was wondering why, too....
     
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  13. Backyard Lumberjack

    Backyard Lumberjack Tree Freak

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    >...so naturally I spend lots of time in my shop!

    LOL! I can relate. I :heart: the sanctuary I call... my shop! KEEP OUT! lol... no dirt, no debris, no chips, just clean. unauthorized entry? no mery! lol. :D

    I support fully the desire for mechanical investigative exploration... given both the motivations and skill-set. :yes:

    it may be a good idea to add a carb rebuild/overhaul to your To Do List. that diaphragm/pump may look like it had been shellacked... after last run.
     
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  14. Backyard Lumberjack

    Backyard Lumberjack Tree Freak

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    there is a lot of valor in honesty! :numberone: as this thread grows, so will the advice. ask any 1,000 racing enthusiasts about what camshaft to run? and you will get 1,000 dif suggestions. lol

    since the saw has not run since early 2,000's... and it had good compression play into your honesty. once u start taking pistons off rods things start to get complicated fast if not done exactly correctly. at 10,000 rpms +/- ... things need to be done exactly correctly. uh-huh!

    KISS! re-ring, deglaze cyl, rebuild carb, sharpen chain, new fuel... and go have fun!
     
  15. Ryan_289

    Ryan_289 ArboristSite Member

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    Thanks for the help guys. I'm fairly mechanically inclined, I work on my farm equipment and have rebuilt a couple of old Willys jeeps, I've just never worked on any 2 stroke stuff. Forums like this are a huge help.

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  16. Ted Jenkins

    Ted Jenkins Firewood by TJ

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    I believe Back has this exactly right. My only thought on a single ring piston is that the compression often does not matter. The compression test is not relevant in many cases. This is because the ring depends upon pressure to expand itself on the cylinder wall. Turning the engine over by hand at least some of the time will not create enough pressure to cause the ring to seal. With duel ring pistons this is much less of a concern. Or in other words the OP must know when a engine needs a new piston and ring as opposed to testing for compression. Thanks
     
  17. rupedoggy

    rupedoggy Addicted to ArboristSite

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    How does it do that?????????
     
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  18. Ryan_289

    Ryan_289 ArboristSite Member

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    Pics of markings on top of piston and the intake and exhaust bottom. Also a closer pic of the scuffing below the intake. It is smooth to the feel. This will most likely be a low hour saw when I'm done.

    So just a re ring and a cylinder scuff with red scotchbrite yall think? If this is a non stock piston, how do I make sure and get the right ring.[​IMG][​IMG][​IMG][​IMG]

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  19. jltrent

    jltrent ArboristSite Operative

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  20. Ryan_289

    Ryan_289 ArboristSite Member

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    It is 48mm. I'll order one of those caber rings.

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