pferdfiler
Husqvarna-Jonsered Fan
Ok smart guy lets cut some real wood,like 20"hard maple.....Then we shall see what tune is best!
390xp Highspeed problem
- Thread starter CoastRangeCutter
- Start date
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Big_Wood
westcoast dweller
Ok smart guy lets cut some real wood,like 20"hard maple.....Then we shall see what tune is best!
Why do you do this to yourself? Lol your saw is slower then a stock one for starters and we get bigger maple then that here. in fact it’s a waste of time so it goes to firewood. If we got a maple on a sideline it’s to be treated like a snag. Dump the POS straight down the hill lol. we don’t need to compare cause damn near anyone’s stock 390 on here would beat yours lol
My wood's bigger than your wood.
My wood's harder than your wood.
My saw's stronger than your saw.
Come on guys.
My wood's harder than your wood.
My saw's stronger than your saw.
Come on guys.
SierraMtns
ArboristSite Operative
How did a high speed adjustment thread for the 390XP turn into a "towel hanging contest"?.....LOL.
Tuning for maximum no-load rpms is NOT how to tune a saw, especially if it has a rev-limiting coil in it. The coil will mimic the 4-stroking caused by a close "H" speed carb setting.
I much prefer to start out just a tad "rich" with the "H" speed screw with noticeable 4 stroking a tad early in the rpm range, then start making cuts and leaning the saw up every so slightly with each cut until it makes the best power. With each cut made remove the load about half way thru the cut and make sure it 4-strokes nicely then cleans up instantly when the load is applied.
With "H" speed tuning, unless you are in some sort of speed cutting contest it is best to er a tad rich than lean. This brings in more lubricant for the engine and reduces piston speed and EGT's, all for the better of the saw in the big scheme of things......IMHO.....Cliff
Tuning for maximum no-load rpms is NOT how to tune a saw, especially if it has a rev-limiting coil in it. The coil will mimic the 4-stroking caused by a close "H" speed carb setting.
I much prefer to start out just a tad "rich" with the "H" speed screw with noticeable 4 stroking a tad early in the rpm range, then start making cuts and leaning the saw up every so slightly with each cut until it makes the best power. With each cut made remove the load about half way thru the cut and make sure it 4-strokes nicely then cleans up instantly when the load is applied.
With "H" speed tuning, unless you are in some sort of speed cutting contest it is best to er a tad rich than lean. This brings in more lubricant for the engine and reduces piston speed and EGT's, all for the better of the saw in the big scheme of things......IMHO.....Cliff
SierraMtns
ArboristSite Operative
KG441c
Keith
Common overlooked issues - is the tank vent partially plugged and is the fuel filter big enough?
That's one way to do it, although I typically er a bit toward the rich side of things vs right on the edge of being lean.
I don't have a saw in my line-up where you are going to be able to adjust it in the cut, so I'll start a cut and stop for each adjustment as I lean it up to find the ideal adjustment where the mixture is correct vs it hitting the rev-limiter.
I'd also clarify that when I saw "er a bit rich" I'm not talking where you are loosing any power in the cut and the saw is "puking" all over itself, not making optimum power, etc. I've just found over the years that being a little conservative is easier on the P/C and I've never once "smoked" on in any of my saws. Matter of fact my 480CD was purchased new in 1989, has at least a zillion hours on it, and P/C and compression are perfect..........Cliff
I don't have a saw in my line-up where you are going to be able to adjust it in the cut, so I'll start a cut and stop for each adjustment as I lean it up to find the ideal adjustment where the mixture is correct vs it hitting the rev-limiter.
I'd also clarify that when I saw "er a bit rich" I'm not talking where you are loosing any power in the cut and the saw is "puking" all over itself, not making optimum power, etc. I've just found over the years that being a little conservative is easier on the P/C and I've never once "smoked" on in any of my saws. Matter of fact my 480CD was purchased new in 1989, has at least a zillion hours on it, and P/C and compression are perfect..........Cliff
CoastRangeCutter
ArboristSite Lurker
wow , some guys got really wound up. all i was trying to do is get some info on why an unlimited coil is not allowing higher rpms than stock. im just experimenting with this saw. and i tuned it just like madsens instructed, and leaned it out a touch to see how it affected rpms. ive been cutting timber for years with stock 390s and this is the first one ive tinkered with. just trying to learn about a more complete function of these saws and how certain mods may help with efficiency. thanks all
KG441c
Keith
Good muffler mod and a timing advance will go along ways
