Stihl MS260 rattle

[NorfolknGood]

I will give it a bit more of a general clean up and blow it out with the airline after 9am then run it up. IIRC the rattle was still there with clutch engaged. It's a regular metallic rattle sounds a bit like a large thin washer on a shaft if you know what I mean.

 

I think the noise is too pronounced and regular to be a loose bolt but I like your thinking

[NorfolknGood]

Just blown everything out with an airline and started her up again. Rattle is still there with chain brake on and I now feel it's more of a clatter than rattle !!! I'm thinking needle bearing or word wrist pin?

[spudulike]

I have found that these saws rattle at the best of times, main reason is piston slap at BTDC. It is basically the piston slapping the cylinder as the lower skirt has worn.

One test is to get the piston at its lowest position and move the flywheel back and forth and see if it rattles or clanks.

 

Other than that, see if the clutch shoes are loose in the central boss - you could run the saw up with no clutch on it to be sure.

[NorfolknGood]

I pulled the barrel off and top ring is stuck at the exhaust port and has left a lil slip in the bore and a slight scuff on the piston. I will report back once I investigate further.

[NorfolknGood]

Piston has a 1mm taper on the exhaust side narrowest on the skirt I guess that means a new bloomin piston to I also hear the after market ones are not to be trusted.

[spudulike]

Piston has a 1mm taper on the exhaust side narrowest on the skirt I guess that means a new bloomin piston to I also hear the after market ones are not to be trusted.

 

There you go, piston slap, 1mm is very excessive but love it when I am right:thumbup:

 

Use a Meteor piston but check the diameter I believe that they are 44mm but the later ones are 44mm. Meteor are close to OEM and check the bore is smooth especially around the exhaust port and I would re-bevel the exhaust port.

 

Your saw has probably mildly seized at some stage, worth investigating why!

[NorfolknGood]

I just took a look at meteorpiston.com ref their pistons but didn't understand the lingo even in English so I have ordered a OEM Piston Assembly 44.7 mm £77. The bore has cleaned up ok with a flap wheel in a drill without ruining the chrome all looks good.

[spudulike]

I just took a look at meteorpiston.com ref their pistons but didn't understand the lingo even in English so I have ordered a OEM Piston Assembly 44.7 mm £77. The bore has cleaned up ok with a flap wheel in a drill without ruining the chrome all looks good.

 

Harsh way of cleaning it but would do the job. The OEM piston will work fine, just cost more.

Make sure you know the reason why it failed before running it hard or do all the normal checks on reassembly.

[NorfolknGood]

Harsh way of cleaning it but would do the job. The OEM piston will work fine, just cost more.

 

I thought that but I was assured by a fella that has been working on Stihl's on a daily basis for years.

I would have gotten the piston you mentioned but went the easy route and threw £ at the problem which I'm not able to do often

 

 

Make sure you know the reason why it failed before running it hard or do all the normal checks on reassembly.

 

Normal checks being check for play on everything, make sure air is getting round cooling fins etc and to make sure plug right heat. Fuel mixture correct on carb and mixed in can.

 

Anything else I missed?

[Stubby]

I thought that but I was assured by a fella that has been working on Stihl's on a daily basis for years.

I would have gotten the piston you mentioned but went the easy route and threw £ at the problem which I'm not able to do often

 

 

 

 

Normal checks being check for play on everything, make sure air is getting round cooling fins etc and to make sure plug right heat. Fuel mixture correct on carb and mixed in can.

 

Anything else I missed?

 

No air leaks causing it to run lean and nip up . No point fixing it if its going to do the same again . Fuel line , impulse line ,crank seals , carb boot , etc etc .....