What the dealer told me today about "Big Brutus" ??

[SawTroll]

.... Under-sizing a bar is as problematic as over-sizing. On say a 361, on a short bar (16) you should be looking at an 8 tooth sprocket (your "gear"). ...

The jury (me) is still out on the 7- vs 8-pin with the 15" bar on my 361.

From my own observations, I am slightly in favor the 8-pin 3/8", but advice on saw forums have been holding me back......

Your post is in fact the first one I have seen on a forum, indicating that the 8-pin is the "right" choise...... :yoyo: :yoyo: :yoyo:

 

[manual]

Talon

This will come very naturally for you!

Just picture a 4-cylinder tune, even at idle, turning the mixture out the engine starts to lope a little, that happens when the mixture is getting a little over 10 : 1 ,,,,,, and when you turn a mixture in on a 4- cycle it falls flat on it's face too lean,,,,,, just favor the too rich side of that spot, you might find that just a 1/16th - an 1/8 of a turn in from a good burble will tach out real close.

To check it from the lean side, there will be a spot were turning the screw just a little in makes a huge increase in rpm's, that's a little to lean, just out from there.

I adjust from the High side. Maybe burble is the wrong sound.
Ok you get a hugh increase in RPMs then it starts to what ? starve for fuel .
turn her ccw to get the rpms steady and the back a hair.
When I adjust from the rich side up. seems always to low of RPMs.
highest vacuum is always on the lean side adjustments.
Hows that for a non drinker,

 

[Lakeside53]

The jury (me) is still out on the 7- vs 8-pin with the 15" bar on my 361.

From my own observations, I am slightly in favor the 8-pin 3/8", but advice on saw forums have been holding me back......

Your post is in fact the first one I have seen on a forum, indicating that the 8-pin is the "right" choise...... :yoyo: :yoyo: :yoyo:

On a 16 inch bar 3/6 I find it true in our western lowland timber, but now I just have multiple saws rather than messing around switching bars/sprockets. My 361 sits with a 7 sprocket, 3/8 rsk full comp and 20 inch.

I was more illustrating a point than dishing out hard facts. Half the time I wouldn't know what size sprocket I was running; the other half I make it up:biggrinbounce2:

 

[ciscoguy01]

confused

The bar length has nothing to do with the "gearing".

You are not changing the "speed at which it runs"... just the speed LIMIT if required. Re-read my longer post a few back.

And NO, you don't change the mixture when you change a bar unless you need to STOP it from exceeding the max design RPM. Chasing the mixture setting all over the place with different bars sizes is a recipe for meltdown.

Under-sizing a bar is as problematic as over-sizing. On say a 361, on a short bar (16) you should be looking at an 8 tooth sprocket (your "gear"). On a medium bar (20-24), a 7, and on a long bar (28), a 7 plus the move to skip chain. Maybe skip at 24 also... The idea is to stay IN the power band while the throttle is wide open.

I once ran an 036 with a 16 bar, 8 tooth sprocket and a full skip chain. Cut 10 inch alder like butter! and I could sharpen the chain in about 1 minute. But in an instant it was real easy to be cutting at 12.5k... and it should have been at 9-10k. I probably should have been running full comp, but...

Be careful on short bars and big saws - the chain needs to be cutting and the HP going into the chips... If you put a 16" bar on a 660, then tune it for max rpm (it will be really rich and not optimal), you can't get a sprocket big enough, so the only option is to move to a bigger chain... Nothing like .404 for throwing chips.


Confused? Good! now go cut some wood

Yea, I really am now. Only thing I know is I should be running my saws a little rich. People told me they'd last much longer if I did that. Guess if I change bars or what not I'll just bring it somewhere. Thanks for the info guy... That was why I was asking. I read the other parts of the thread and didn't understand what was being said.