I forget, does OP have the IPL and shop manual?
Cannot start MS260
- Thread starter deanbrown
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He was sent them yes.
You can use a 80 grit Dremel flapper on a Dremel tool and get most of it off. Just keep it in mind that it takes patience. The nikasil is maybe as little as two thousandths thick. And, that is a lot of transfer. So, it will be a job to really get it clean and slow and patient. You can see it if you get through the plating.
A little spot is not the end of the world. But, you want to keep the plating intact.
A little spot is not the end of the world. But, you want to keep the plating intact.
What he said, be careful not to burn through the plating.
SteveSr
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Stihl dealers are not allowed to sell parts mail order / online or they could loose their dealership. That being said you can sometimes find new OEM parts online at places like Ebay.
Dealers are also free to set their own price markups so shopping might save you some money. John Deere and Northern Tool are also Stihl dealers and have better pricing than the now Stihl monopoly in my area.
Also as I recall that the engine displacement was increased which changed the piston/cylinder size so the piston and cylinder have to match.
Apologies for ignoring this thread for the last few days - I've had car shudders/vibrations to fix, replaced whole house heating, land surveyors, land clearing and a load more crap to deal with all at the same time. But I am really looking forward to getting back to this chainsaw job! 
Update appreciated.Apologies for ignoring this thread for the last few days - I've had car shudders/vibrations to fix, replaced whole house heating, land surveyors, land clearing and a load more crap to deal with all at the same time. But I am really looking forward to getting back to this chainsaw job!
Twitchy car suspension usually equates to sloppy tie rod ends or a wallowed out Pittman arm. The mating splines do wear out (become rounded off) after a fashion. What always irks me is the fact that modern tie rod ends don't come with grease fittings today, IOW planned obsolescence and eventual replacement. One thing I always do with them is I left hand drill them and tap them and install grease fittings.
That and the 'plastic' inserts in modern ball joints. The plastic inserts give out as well, especially the 'no grease' ones. Once the rubber boots give out, it's only a matter of time before they fail as well. When the boots fail, road grime gets in and 'machines' them quite nicely.
Suspension parts all live in a very nasty atmosphere, all that road grime thrown up by your tires has a nasty habit of destroying suspension parts before their time. I replace all my own but it does entail specific tools to accomplish that. Have fun and hopefully eliminate that shimmy-wiggle without severely draining your wallet.
Just had our central furnace replaced this fall. Heat exchanger failed and it wasn't a cheap date either. The new high efficiency furnaces are not only complex but the failure rate as well as replacement costs are high. I did save the main blower from the old one however. I'll use it in the shop as an 'air mover'. Had our 'up north' property surveyed as well and that wasn't cheap either but then nothing is 'cheap' today far as I can tell.
That and the 'plastic' inserts in modern ball joints. The plastic inserts give out as well, especially the 'no grease' ones. Once the rubber boots give out, it's only a matter of time before they fail as well. When the boots fail, road grime gets in and 'machines' them quite nicely.
Suspension parts all live in a very nasty atmosphere, all that road grime thrown up by your tires has a nasty habit of destroying suspension parts before their time. I replace all my own but it does entail specific tools to accomplish that. Have fun and hopefully eliminate that shimmy-wiggle without severely draining your wallet.
Just had our central furnace replaced this fall. Heat exchanger failed and it wasn't a cheap date either. The new high efficiency furnaces are not only complex but the failure rate as well as replacement costs are high. I did save the main blower from the old one however. I'll use it in the shop as an 'air mover'. Had our 'up north' property surveyed as well and that wasn't cheap either but then nothing is 'cheap' today far as I can tell.
Hello again, I'm trying to get to this ms260 piston - a couple of q's - when you talk of the wrist pin, do you mean the one right by the piston top or the one near the bottom (behind B in the pic)? Does a replacement Stihl piston typically come with this arm? Also, is B a regular right-handed thread? Any tips on holding the piston still when undoing this? I also picked up the tool C that one of you mentioned. Does that push this fan wheel off?
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Behind A is the wrist pin there is a clip you pry out, look close it's tiny. Yes, pistons typically come with wrist pins and clips, don't lose the clips. The flywheel nut comes off counterclockwise, wrap a rag around d the piston put your palm down hard pushing it to the bottom while taking that nut off the flywheel CC wise with an impact gun don't hold the flywheel with tools instead you could break a fin off the flywheel! Oh, and that tool screws in to the flywheel at this point look it up on youtube.
I’ve got my 37% hydrochloride acid out here now and rubbing it onto the aluminum crud. Do you typically see any kind of reaction/bubbling or any black stuff coming off? This is the first time I’ve done this. I removed all oil with alcohol and sanded it gently with 1000 grit.
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37% night be a bit mild- when you pop the lid on the main container does it emit vapours and sting your nostrils?
Should bubble and fizz on aluminium and not hurt the plating- do not let it run into the ports though!
1000 grit is a bit mild, try around 220 for initial cuts.
Should bubble and fizz on aluminium and not hurt the plating- do not let it run into the ports though!
1000 grit is a bit mild, try around 220 for initial cuts.
I’m
i think 37% HCl is about as strong as it can be, and yes it is fuming and pungent. It’s not like H2SO4 or HNO3 which can be pretty much 100%.
I've always used easy off oven cleaner myself. What we used to use on snowmachines that got stuck. That and a small prick punch to pop it off.
Ok this is how it has turned out. It feels a smooth as the other side of the cylinder, completely smooth. I went over it with 400 grit and acid, and then 1000 grit to finish it off. Do you think this is ready? I have a new Stihl piston and rings.
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Looks clean- as long as you cannot catch a finger nail on anything lowered or raised- slap her together.
SteveSr
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I still see vertical lines which may just be shined up transfer that is still there and must be removed. The vertical lines obviously aren't into the plating so it must still be transfer.
Whatever oil is on the cylinder in the photo is obscuring what is really there.
Do a search on the site for "removing transfer without acid". In there you'll find the final step of using red scotchbrite on a mandrel.
Also don't forget a final clean of the cylinder with dish soap or chuck it in the bottom rack of the dishwasher when the wife/s.o. isn't looking!
You should be able to dab some muratic acid on the lines and see if you get a fizz.
Cameras really high light insignificant scratches depending on the light .
Cameras really high light insignificant scratches depending on the light .
