Author Topic: 028S - worn piston  (Read 344 times)

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Offline qigley

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028S - worn piston
« on: October 27, 2016, 10:37:16 am »
Hi everyone..
Im a bit of a noob when it comes to repairing saws.

I have a 028S with a scored piston, low compression, and blowback,  so its engine reco time. Do you  rebore the cylinder and use oversize pistons, or get a complete new cylinder and pistons assembly? Both can be got off Ebay   for $50 and $120 respectively.
Also are there any tests I should do on the machine before pulling down, such as the crank seals, etc.

Thanks

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Offline Cut4fun .

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Re: 028S - worn piston
« Reply #1 on: October 27, 2016, 12:23:18 pm »
No reboring as the cylinders are plated. Just find out why yours scored and then rebuild.  If you cant clean your cylinder up (most you can), you buy used or new cylinder. Piston kit too.
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Offline jmester

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Re: 028S - worn piston
« Reply #2 on: October 27, 2016, 07:30:29 pm »
Check your hotmail. Sent you a service manual. Hope it helps.
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Offline Al Smith

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Re: 028S - worn piston
« Reply #3 on: October 28, 2016, 05:02:51 am »
It depends on weather the piston is scored or scuffed .Scored most likely  is caused by a lean run condition and will transfer aluminum to the cylinder and the damage will be on the exhaust side .Scuffed is slight damage on the intake side and could be nothing but a faulty air cleaner ,Usually no transfer .

On a scuffed intake side unless it's real bad all it might take is a set of piston rings .Fact I have several that all it took was a little clean up with a 3M pad,rings and good to go .You can't tell them from a brand new one .Some it took a new piston .

Offline qigley

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Re: 028S - worn piston
« Reply #4 on: October 28, 2016, 03:20:38 pm »
Check your hotmail. Sent you a service manual. Hope it helps.
thanks that would be handy but I never received it.   

Thanks to other for their replies. I'll attempt to pull it down and see whats what.

Offline Cut4fun .

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Re: 028S - worn piston
« Reply #5 on: October 28, 2016, 07:00:22 pm »
Check your hotmail. Sent you a service manual. Hope it helps.
thanks that would be handy but I never received it.   

Thanks to other for their replies. I'll attempt to pull it down and see whats what.

Check your spam folder for SM.  Still using the hotmail?
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Offline qigley

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Re: 028S - worn piston
« Reply #6 on: October 28, 2016, 07:27:06 pm »
Check your spam folder for SM.  Still using the hotmail?
yeah still using it, I checked all folders, nothing. I changed it to a gmail address, can you send it there, pls? Thanks

Offline oldpro

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Re: 028S - worn piston
« Reply #7 on: November 12, 2016, 10:20:38 pm »
How badly is the piston damaged, is it obviously melted and scraped up or the there just some small scuffing in a small area? A couple photos would help. Is the damage to the piston on the exhaust or intake side? Also find out and determine if the cylinder is really damaged,often the cylinder can be repaired saving you a lot of money. A new piston assembly(Or piston and cylinder assembly) is available from several makers.

Offline qigley

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Re: 028S - worn piston
« Reply #8 on: November 12, 2016, 11:16:49 pm »
How badly is the piston damaged, is it obviously melted and scraped up or the there just some small scuffing in a small area? A couple photos would help. Is the damage to the piston on the exhaust or intake side? Also find out and determine if the cylinder is really damaged,often the cylinder can be repaired saving you a lot of money. A new piston assembly(Or piston and cylinder assembly) is available from several makers.
Ive just looked at the piston thru the exhaust port. doesnt look good to me.  Motor starts ok, but there is a fair bit of blow by back out the carb.. Im going to pull this apart soon.

Offline jmester

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Re: 028S - worn piston
« Reply #9 on: November 13, 2016, 06:24:41 am »
I can send you the manual to your gmail as long as you updated your profile page here. Also based on the pic looks like you have a 029 super. A clamshell engine design.
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