stihl Replacing cylinder and piston Stihl MS 260

[Craig Howe]

My trusty Stihl MS 260 has a warn cylinder, I do most work on my saws myself but having never replaced a pot and piston, is there anything technical I need to know about? Is it a straight swap or do I need to set anything?

 

cheers

[billpierce]

Straight swap. You may want a new gasket in case your old one breaks. Worth finding the cause of the seizure.

Some good in-depth vids on YouTube. Donnyboy is pretty good.

Make sure piston is correct way and be careful with piston rings when placing cylinder over.

Meteor are decent non original parts.

[EricBradley]

• I'm guessing you've not removed it yet, how do you know its worn?

[Craig Howe]

50 minutes ago, billpierce said:

Straight swap. You may want a new gasket in case your old one breaks. Worth finding the cause of the seizure.

Some good in-depth vids on YouTube. Donnyboy is pretty good.

Make sure piston is correct way and be careful with piston rings when placing cylinder over.

Meteor are decent non original parts.

Thanks bill ??

[Craig Howe]

46 minutes ago, EricBradley said:

• I'm guessing you've not removed it yet, how do you know its worn?

It has running issues, I thought maybe carb, I dropped it into my local machinery shop, they diagnosed warn cylinder 

[bmp01]

42 minutes ago, Craig Howe said:

It has running issues, I thought maybe carb, I dropped it into my local machinery shop, they diagnosed warn cylinder 

As Eric suggests not likely to be a worn cylinder, the metal plating on the inside of the cylinder is very hard wearing.  Usually any wear is limited to the piston rings and piston. Probably the test they did in the shop was a compression test - it just tells you how much gas leaks part the piston assembly. From the outside there's  no way of knowing which aspect of the piston assembly is responsible. Could be just the piston rings stuck ring grooves though to piston assy and cylinder repacement if its been seized...

If the shop pulled the exhaust off (to inspect the piston through the exhaust port) then maybe they diagnosed a seized piston but usually that results in an engine that doesn't run at all, not running problems. 

Take the exhaust off have a look for your self.... just 2 torx screws and 5 mins.

 

 

[Stretchsaws]

Agree with above. First and easiest job is to pop off the muffler and have a gander. Work the piston up and down and give the ring a gentle prod with a small screwdriver to check that it does flex. 

Unfortunately some workshops don't have a clue or aren't interested enough to work on small 2 stroke equipment, so they fudge it off by saying 'not economical to repair.' I know because I've had to do it, it's down to my service manager, not me personally. 

If the top end looks naffed, then give it a go replacing, but should only be done after finding the cause of the damage. Try to find a local shop/person that actually know what they're doing, or if you're in Suffolk, come and see me! ☺

[EricBradley]

If you tell us the running issues your saws having we may be able to point you in the right direction

[Craig Howe]

22 hours ago, bmp01 said:

As Eric suggests not likely to be a worn cylinder, the metal plating on the inside of the cylinder is very hard wearing.  Usually any wear is limited to the piston rings and piston. Probably the test they did in the shop was a compression test - it just tells you how much gas leaks part the piston assembly. From the outside there's  no way of knowing which aspect of the piston assembly is responsible. Could be just the piston rings stuck ring grooves though to piston assy and cylinder repacement if its been seized...

If the shop pulled the exhaust off (to inspect the piston through the exhaust port) then maybe they diagnosed a seized piston but usually that results in an engine that doesn't run at all, not running problems. 

Take the exhaust off have a look for your self.... just 2 torx screws and 5 mins.

 

 

Thanks, I’ll take a look

[Craig Howe]

21 hours ago, Stretchsaws said:

Agree with above. First and easiest job is to pop off the muffler and have a gander. Work the piston up and down and give the ring a gentle prod with a small screwdriver to check that it does flex. 

Unfortunately some workshops don't have a clue or aren't interested enough to work on small 2 stroke equipment, so they fudge it off by saying 'not economical to repair.' I know because I've had to do it, it's down to my service manager, not me personally. 

If the top end looks naffed, then give it a go replacing, but should only be done after finding the cause of the damage. Try to find a local shop/person that actually know what they're doing, or if you're in Suffolk, come and see me! ☺

Yes I’ve had the ‘not economical to repair’ fob off before in the past, thanks for the advise, I’m afraid I’m in Somerset but thanks for the offer ??