Piston of Stihl MS361 Clone Kit Saw

[arto98607]

Hi all,
I am a homeowner and could not justify buying larger new professional OEM saws for my occasional use so couple of years ago decided to build couple of clones since my Husky 162 and Stihl AV031 are pretty old.

I built MS660 and 361 clones from kits and both have worked out very well, except some difficulties in tuning the 361 due to very restricted muffler it came with, making it difficult to hear "burbling" stop and engine cleaning up when loaded. Apparently others have had similar issue with MS361's.

No such difficulty at all with the 660 kit saw.



I have now switched 361 to "Rippa" muffler and it's easy to hear burbling stop when saw engine is loaded.
Photo below was taken while changing mufflers.

Question:
Are the vertical "scratches" just above the top piston ring normal? (Please zoom in on the photo)




New muffler, no more trouble tuning in:

 

[dieselscout80]

What is a clone MS361?

 

[arto98607]

OK I have edited the post title!

Farmertec MS361 kit of complete 100% set of spare parts for Stihl MS361

 

[dieselscout80]

Thanks

 

[xyz123]

It's a G366 farmertec copy.

Mine ran as good as my oem one did with muffler mods on both. These need it IMHO.
I just do free no cost muffler mods.

They seem to be more of the problematic clones for owners though.

 

[xyz123]

I honestly can not see anything wrong with your piston and rings in your pic.

 

[arto98607]

I agree the rings look great, but if you zoom in the photo you will see what I think is a band of short vertical scratches indicating metel to metal contact.

Just wondering if that is normal?

 

[ruffdog]

Many moons ago I was involved in a reseller of cheap big-bore kits and aftermarket cylinders. We found the quality was spotty and the cast seemed dirty with sand. Those scratches sure look like it is from "dirt" but it could also be from the quality of the mating parts like the cylinder wall.

 

[arto98607]

Many moons ago I was involved in a reseller of cheap big-bore kits and aftermarket cylinders. We found the quality was spotty and the cast seemed dirty with sand. Those scratches sure look like it is from "dirt" but it could also be from the quality of the mating parts like the cylinder wall.

I agree and don't think it's normal to have markings like that!

Oh well, the saw works good and I will keep using it but will soon order better quality cylinder & piston.

Used it to fell about 70 hybrid poplars just before taking the photo of the piston.


Not looking for big bore, just regular MS361 47 mm set - I am open if anyone here has suggestions on suppliers?



Felling was the easy part, now the real work begins:

 

[dodge man]

I agree, the scratches don’t look right but they don’t extend down onto the rings. A pic of a MS 250 that had a badly damaged piston and rings, yours doesn’t look near as bad.

 

[xyz123]

I see some once blown up. But I have seen that on other saws that ran great newer or older oem too.

Could be rough bevel in exhaust area etc. Why lot of guys guys the extra mile to smooth out the bevels in the afm cylinders.

Without going OEM on stuff. I used to use meteor but their quality has dropped on some kits.
But to the point I been using Chris's piston kits in a few saws with great results. Feedback from others is what made me give them a try. THE DUKE'S PERFORMANCE COATED PISTON FITS STIHL MS341 MS361 HOLZFFORMA G366 47MM

Great feedback on his p+c kits too. THE DUKE'S NIKASIL PLATED PISTON AND CYLINDER FITS STIHL MS361 KIT 47MM HOLZFFORMA G366

 

[arto98607]

Thank you, I just ordered Dukes set and will update once it's installed and been running for awhile!

 

[dieselscout80]

It's a G366 farmertec copy.

Mine ran as good as my oem one did with muffler mods on both. These need it IMHO.
I just do free no cost muffler mods.

They seem to be more of the problematic clones for owners though.


View attachment 761450View attachment 761451View attachment 761452

Can you elaborate on how you do your muffler modification on a MS361?

 

[xyz123]

Can you elaborate on how you do your muffler modification on a MS361?

I for one am not opening the inside of muffler by uncrimping to remove all the restriction inside. I just open the outside with a deflector or gill. Some use a pipe.

 

[dieselscout80]

I just open the outside with a deflector or gill. Some use a pipe.

Sorry I‘m not sure I understand this part.

 

[xyz123]

Sorry I‘m not sure I understand this part.

Look at the 3 pics you quoted me in on your first post. Shows it and self explanatory. That one is a gill.

 

[dieselscout80]

Look at the 3 pics you quoted me in on your first post. Shows it and self explanatory. That one is a gill.

Oh the opening on the side of your muffler. I was thinking of tools to do it with.

How much louder is it with the modified muffler?

 

[xyz123]

Oh the opening on the side of your muffler. I was thinking of tools to do it with.

How much louder is it with the modified muffler?

Since the baffle is still inside. Not much louder at all.

These saws are just so choked from factory, like a 290-390 too is bad.

On a 290 I seen 23% gain in faster cuts just by opening the muffler. Those are the worst choked ones. I can go right through their baffle and by pass it on those.

Now doing like this cant go got in areas that require spark screens. If that you need to use a deflector with screen under it.

 

[arto98607]

I considered opening up, gutting & re-welding the crimped seam in the muffler of my MS361 clone, but decided it was better to buy one already modified.

Sure I could have saved $65 but would have easily spent couple of hours messing with the stock muffler....

 

[xyz123]

I considered opening up, gutting & re-welding the crimped seam in the muffler of my MS361 clone, but decided it was better to buy one already modified.

Sure I could have saved $65 but would have easily spent couple of hours messing with the stock muffler....


View attachment 762681

I wonder if he cut and removed the baffle inside or just cheats like me and just add more outer opening. No cost that way.