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Narrow Kerf Combined with Muffler Mods?

Started by tigpoz, February 05, 2007, 04:52:08 PM

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tigpoz

I had a Husky 359 (59cc) until someone borrowed it from my pickup, so I'm looking for a replacement saw.  On that 359 I had replaced the stock 20" bar 3/8 chain & sprocket with narrow kerf 18" .325 x .050 bar, .325 sprocket & 95vp chain.  I was pleased with it.

So I've been trying to figure out what saw I want now, and I am thinking the Stihl 361 is nice. I'd like to fit out a Stihl 361 (which is also 59cc) with the narrow kerf 18" .325 x .050 bar, sprocket & 95vp chain.  --- But also, I've been reading here about the power advantages of muffler mods and that sounds like a very good idea so I'd like to do that too. 

--- My question is this:  The Oregon info on the 95vp chain says it is intended for bars up to 20" on saws up to 62cc.  I'm within those guidelines with the 59cc Stihl 361, but near the limit.  If I modify the muffler on a 361, and run 95vp chain, does that increase the stress on the chain enough to have crossed over into "Not Safe" territory?  Or are the power increases from the muffler mods not going to have much effect on the chains' limits.  I'm sure there is a wide margin of safety built into Oregon's recommendations for limits on the 95vp or any chain, so I wouldn't worry about pushing a little past the limits, but I wouldn't want to find out the hard way that I was overlooking some factor.
--- So, Stihl 361 with moded muffler running 95vp chain-- Reasonably safe, or not?

Thanks

Michael

If you like 325 chain, run it. I modified a 088 Stihl for a guy to use on his mill. It had lots of power and he never had a chain break. He had several customers that had big mills also use 325 without problem. Stretching and jumping out of the rim/sprocket or bar is more of a problem than breakage.    Mike
If you need saws or parts I may be able to help.

Tony_T

I've run narrow kerf Stihl (picco) 3/8 chain on an 066 with 25 in bar on my chainsaw mill without a problem. I think you'd need a 3/8 sprocket compatible with the 361.

SawTroll

Quote from: Tony_T on February 06, 2007, 03:51:54 PM
I've run narrow kerf Stihl (picco) 3/8 chain on an 066 with 25 in bar on my chainsaw mill without a problem. I think you'd need a 3/8 sprocket compatible with the 361.

3/8" Picco is standard on the Logosol version of the 660 here.

On the other side, I am pretty sure that a .325 setup on a 361 will be faster with RS/RSC chain, than with 95VP.
The 95VP is at its best on 40-50 cc saws, where the reduced resistanse in the cut more than compensates for the less efficient cutters......

If you want to use a smaller than 9-pin .325 sprocket, you will have to change out the clutch for a small spline one (I don't know if they exist at all).
Information collector.

ComputerUser

The 361 is faster with 3/8" 7-pin than with .325" 9-pin, especially if it is muffler modded.  Skip the .325" idea, it isn't worth your time or effort. 

A buddy who posts at the other site ran 3/8" 7-pin on his 361 with 16" through 28" bars in hardwood (the 28" was just for kicks), and when muffler modded the saw was very happy with that setup.  The same saw with .325" was, well, let's just say that after he tried the saw with 3/8" instead I got a great deal on a nearly-new .325" bar and some loops to run on my 026Pro.

If performance is your ultimate goal, the 361 when modded (woods porting, not just muffler mod) is a heck of a machine.  Cuts just two seconds behind a modded Husqvarna 372 in 20" hickory (17 seconds versus 15 seconds) when we side-by-sided them a few weeks back.

jokers

Quote from: ComputerUser on February 10, 2007, 07:44:05 PM
A buddy who posts at the other site ran 3/8" 7-pin on his 361 with 16" through 28" bars in hardwood (the 28" was just for kicks), and when muffler modded the saw was very happy with that setup.
 Who is your buddy ComputerUser? Can you tell us in greater detail the conditions of this test where he ran the 28" bar in hardwood? Thanks.
Quote from: ComputerUser on February 10, 2007, 07:44:05 PM
If performance is your ultimate goal, the 361 when modded (woods porting, not just muffler mod) is a heck of a machine.
They sure are! Here is a pic of several saws getting ready to go under the knife over the next few days, notice the three 361s!   
*edit*  You were going to see a picture of some saws but the hoops that you have to jump through to post a picture here have dissuaded me from doing so. The picture is available elsewhere.

beenthere

C'mon Jokers
4Woody got er dun, you can too.  ;D

Lookin forward ta seein the 361's
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

ComputerUser

Quote from: jokers on February 10, 2007, 09:20:27 PM
Quote from: ComputerUser on February 10, 2007, 07:44:05 PM
A buddy who posts at the other site ran 3/8" 7-pin on his 361 with 16" through 28" bars in hardwood (the 28" was just for kicks), and when muffler modded the saw was very happy with that setup.
Who is your buddy ComputerUser? Can you tell us in greater detail the conditions of this test where he ran the 28" bar in hardwood? Thanks.

Not too much to tell, really.  The saw was near-new with a muffler mod and it did OK with the 28" in white oak, which is more than had been anticipated.  Bogging could be induced, obviously, but the saw made a good showing all the same.  Times weren't taken or comparisons made, it was just a "gee, I wonder if it would work" sort of thing.  It wasn't any 066, but for the guy who only occasionally gets into bigger hardwood this combo with skip chain would work reasonably well without making him buy a big saw that he really doesn't need for the other 99% of what he cuts.

EDIT: Geez, foreget this "Must be in ForestryForum Gallery bit.  What's so wrong about linking to photo_bucket?!  Heck, I can't even say photo_bucket, it would seem!  I had some nice pics to post...no dice, it would seem...

Quote from: jokers on February 10, 2007, 09:20:27 PM
Quote from: ComputerUser on February 10, 2007, 07:44:05 PM
If performance is your ultimate goal, the 361 when modded (woods porting, not just muffler mod) is a heck of a machine.
They sure are! Here is a pic of several saws getting ready to go under the knife over the next few days, notice the three 361s!   
*edit*  You were going to see a picture of some saws but the hoops that you have to jump through to post a picture here have dissuaded me from doing so. The picture is available elsewhere.

This was the test log.  (EDIT: Imagine a 20" hickory log elevated off the ground)   Just playing around, but this saw made it through within two seconds of a modded 372.  20" GB, Stihl RS, 8-pin.  The saw was built by Dave Neiger.  It actually ran a bit faster than my muffler-modded 7900, though I was running some crummy off-the-roll GB round chisel.

I've run this saw with 16" 8-pin in both white oak and hickory.  Very impressive.  If I was starting over and didn't have a bunch of saws already, I could meet all my cutting needs with this saw, something small like a Dolmar 401 or an MS200, and my 075.

Furby

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