MS441 Big Bore rebuild and M-Tronics

[AgTech4020]

Hi folks,

So I just purchased a pair of used and abused STIHL MS441 saws. Both saws were skidder modified but I’ve been able to build a running saw from the remains of the two. Upon getting the saw running I’ve discovered it’s tired, 115 psi compression. No scoring on intake or exhaust side just dull and worn inside but otherwise runs fine. My plans are to order a Farmertec big bore kit for it. The parts saw is a Early M-tronic saw and I would like to move the M-tronics to this saw. My primary concern is will the M-tronics work well with a ported big bore?

Thanks!

 

[alexcagle]

It can handle just about any mods just fine.

 

[Mad Professor]

Not sure about mtronic but I'd pony up for an OEM piston rather than a big bore kit if cylinder is O.K.

 

[AgTech4020]

Not sure about mtronic but I'd pony up for an OEM piston rather than a big bore kit if cylinder is O.K.

The cylinder isn’t scored but looks dusted as if it was run with the air filter loose. There is no visible cross hatching left.


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[Mad Professor]

The cylinder isn’t scored but looks dusted as if it was run with the air filter loose. There is no visible cross hatching left.


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Cleanup the cylinders with some scotch brite then check piston cylinder clearance with some feeler gauges. Post some pictures of each from both saws

 

[AgTech4020]

Cleanup the cylinders with some scotch brite then check piston cylinder clearance with some feeler gauges. Post some pictures of each from both saws

I disassembled it tonight. Found some light scoring around the bottom of the intake port otherwise not bad. I can only fit a .002” feeler gage between the piston and cylinder. Tried a .004” but no go. The scored section of the cylinder can only barely be felt with a thumb nail.



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[Maintenance supervisor]

Did ya get it running? Got apare parts?

 

[AlphaTech]

Did ya get it running? Got apare parts?

Nice saw bro. Looks like it is running great. Wanting to put the 52mm kit on my saw. Does it make a significant difference in power?

 

[AlphaTech]

Hi folks,

So I just purchased a pair of used and abused STIHL MS441 saws. Both saws were skidder modified but I’ve been able to build a running saw from the remains of the two. Upon getting the saw running I’ve discovered it’s tired, 115 psi compression. No scoring on intake or exhaust side just dull and worn inside but otherwise runs fine. My plans are to order a Farmertec big bore kit for it. The parts saw is a Early M-tronic saw and I would like to move the M-tronics to this saw. My primary concern is will the M-tronics work well with a ported big bore?

Thanks!

Why would you want to go from carb to m-tronic unless your changing elevation alot? These saws got alot of hate because they were the first to recieve the m-tronic carb and were also the first strato port saw. They had alot of problems with the mtronic version. Between that and it weighing as much as a 462 but with less power and the av system being slightly floppy with a big bar they did not recieve much love. I have the non-mtronic and my saw has run great from day 1.

 

[OM617YOTA]

Six year old thread.