Inside the 572xp

[MustangMike]

Also, a 2 ring piston! Imitation is ...

 

[StephK87]

mhh, not really matching


also interessting, no difference anymore with these caps between the 572xp and the 565 (like on the 545 to 550), cylinder/piston kit has the same part number.

 

[StephK87]

these bearings on both sides

 

[StephK87]

these screw are just there to hold the cover in place

 

[huskyboy]

Also, a 2 ring piston! Imitation is ...

They’ve had 2 ring pistons on some saws since the late 70s I believe. Two thin rings on the early 181se. Mostly 1 1.5mm ring though on a lot of saws. 394 has 2 1.5mm rings and the 395 2 1.2mm rings.

 

[StephK87]

Here some weights (without the brake handle and crank stuffers)

dry out of the box


fully fuel'd up





fully fuel'd with a 20" stihl rollomatic and chain

 

[StephK87]

time to get the numbers down


Stock squish with the gasket

 

[huskyboy]

Thanks @StephK87 for doing the tear down. I’m wondering where the “dirt” came from. I’ve had stuff fall into the case just taking a cylinder off even after cleaning the area. Maybe some of those dust/magnesium particles from the drilled screw holes fell in that you saw under the muffler? Just a guess. I always flush my case out whenever I take a cylinder off for this reason of stuff potentially falling in even if I don’t see anything.

 

[concretegrazer]

Very interesting how it feeds from the front like a Stihl 461 or 661! Don't most 4 port Huskies feed from the sides?

The 550 & 560's are front fed.

 

[StephK87]

Here some first thougts of the saw.

Handling feels good, like on all 5xx saws to date. Great center of gravity. It looks like they really paid the most attention to solve the heat problems. LOL i don't run it so far, cutting vids will follow this week.
Castings and plastics are ok, not the best in the game but ok, it cant match the overall haptics of the 462.

The case seems not that much heavyer than the case of the 462 (flywheel feels also much lighter on the 565), in my opinion most of the extra weight are coming from the bearings, that big heavy muffler, and from the huge spaced cylinder (especialy fins).

One thing confuses me, between 565 and 572xp. If most of the important parts are the same (case, bearings, cylinder, piston, carb, fly wheel, muffler etc.) where the heck is the huge power gab on paper coming from?

The only differences i've found so far, are the crank stuffers and the ignition modul. I can't really believe this will cut down 1hp in power

here's a stock numbers comparison, the 545 for example dont have crank stuffer like the 550 and it has these smaller transfer caps, but on paper there only 0,3kw away from each other.




i already ordered a 572xp ignition modul (and crank stuffers later) to put it on the 565. Interessting to see how the carb will handle it.

 

[nohoff]

Maybe its only the programmed timing advance.
Like some degree earlier Ignition on the 572 XP at 8000 rpm.
They both have different vibration values on those specs.

Do they have different clutches or springs?
Cause the have different clutch engage speeds.

 

[TreeLife]

Excellent information!! Thanks man

 

[StephK87]

Here are the stock numbers (with gaskets)

exhaust 101° from tdc, 158° duration

intake 74° from tdc, 146° duration

transfers 115° from tdc, 130° duration

compression is near 160 psi (the saw has no runtime)

 

[mdavlee]

Very interesting how it feeds from the front like a Stihl 461 or 661! Don't most 4 port Huskies feed from the sides?

575/576 fed like that since the mid 2000s. Most of the saws over 50cc had 2 rings since 2001 or so.

 

[Dub11]

575/576 fed like that since the mid 2000s. Most of the saws over 50cc had 2 rings since 2001 or so.

That predates the 461/661 right?

 

[huskyboy]

I’ll take those bigger bearings for the modest weight increase. If you think about it it weighs the same as a xtorq 372, has more power and larger bearings. If someone’s running a oregon rw on a 572 and a standard bar on a 462 the 462 will most likely be heavier.

 

[mdavlee]

That predates the 461/661 right?

Yes

 

[Dub11]

Yes

Cool wasn't sure.

 

[concretegrazer]

I’ll take those bigger bearings for the modest weight increase. If you think about it it weighs the same as a xtorq 372, has more power and larger bearings. If someone’s running a oregon rw on a 572 and a standard bar on a 462 the 462 will most likely be heavier.

Same weight and power on paper as a 576. Which seems to have been a dud in the marketplace. More to it than paper stats but it is what it is.

 

[TreeLife]

I'd like to run a 572 and 462 back to back. As a full time logger reduced weight is always rewarding, but not at the sacrifice of power or longevity. Endurance of the machine is most important to me, can't be replacing/rebuilding 1000 plus dollar powerheads all the time