Husqvarna 564xp (g) fuel inject

[el33t]

I wonder if an offset rod like in a diesel would be any benefit to torque on a short stroke saw since all that it does is give it a more efficient angle to transmit force to the crank but maybe with that angle being changed it would increase vibration. I know an outboard clutch has some benifits but I still think they suck personally, also I’d someone is buying a saw to run a 28-32” bar all the time 60cc class isn’t their saw in any color.

But is it true that increased stroke means increased torque? If we increase the stroke (that is, the length of the crank), then for the same engine displacement, we reduce the bore, which also means the area of the piston on which the gas pressure acts. This surface area decreases proportionally to the change in stroke (displacement = area * stroke) that is, with the same BMEP, a proportionally smaller force will act on the crank (Force = pressure * area), which means that considering only the mechanics, the torque will remain the same.

Can you tell why an outboard clutch, other than making it harder to mount the chain/bar, sucks?

 

[lehman live edge slab]

But is it true that increased stroke means increased torque? If we increase the stroke (that is, the length of the crank), then for the same engine displacement, we reduce the bore, which also means the area of the piston on which the gas pressure acts. This surface area decreases proportionally to the change in stroke (displacement = area * stroke) that is, with the same BMEP, a proportionally smaller force will act on the crank (Force = pressure * area), which means that considering only the mechanics, the torque will remain the same.

Can you tell why an outboard clutch, other than making it harder to mount the chain/bar, sucks?

It is a personal preference I understand but yes the main reason is the mounting bar and chain which isn’t as bad under normal conditions but it isn’t real fun to get the powerhead off the bar if it gets pinched while felling a tree. Also I deal with plenty of huskies that guys can’t seem to remember to make sure the brake is off before prying the cover off with brake set. They always say they just thought it was packed with sawdust and didn’t think to check brake. Far as long stroke if it doesn’t give more leverage and torque why build a slower reving worse vibrating engine? If you increase the stroke on the crank with the crankshaft journal moving the applied force further from the cranks centerline it should give you more leverage on the crank in my thoughts and that’s what I’ve always understood from what I’ve read. Granted other stuff comes into play in the whole thing but maybe I’m way off base and they should all have huge bores and a tiny stroke.

 

[sawmikaze]

But is it true that increased stroke means increased torque? If we increase the stroke (that is, the length of the crank), then for the same engine displacement, we reduce the bore, which also means the area of the piston on which the gas pressure acts. This surface area decreases proportionally to the change in stroke (displacement = area * stroke) that is, with the same BMEP, a proportionally smaller force will act on the crank (Force = pressure * area), which means that considering only the mechanics, the torque will remain the same.

Can you tell why an outboard clutch, other than making it harder to mount the chain/bar, sucks?

One of my really unpopular opinions is...

I wish all my saws had an outboard clutch.

 

[lehman live edge slab]

One of my really unpopular opinions is...

I wish all my saws had an outboard clutch.

Why is that? Worried about heat dissipation? Just curious why you like the outboard better? Definitely not saying one is better than the other just more a matter of opinion i believe. They say the outboard clutch is supposed to be easier on crank bearings but I’m not sure if this is the case or not since the old saws of both types survived well, seems just the newer saws have exhibited bearing issues more and that’s due to stratto saws and 50:1 more than clutch design.

 

[afleetcommand]

Looks great, I'll believe it when I see one as there literally is no dealer presence anymore here. Great in theory... I'll run my Junk pile 572's and new 585's.

 

[Woodpecker]

One of my really unpopular opinions is...

I wish all my saws had an outboard clutch.

I want to hear more about the tiny stroke

 

[David Young]

I want to hear more about the tiny stroke

And a picture is worth 1000 words...

 

[Ketchup]

I want to hear more about the tiny stroke

I’m sure he could send you pictures.

 

[Tor R]

The biggest advantage of the outboard clutch is that the bar and chain come closer to the center of the chainsaw.

 

[lehman live edge slab]

The biggest advantage of the outboard clutch is that the bar and chain come closer to the center of the chainsaw.

I know that’s supposed to be one of the benifits which makes them better balanced and better handling but in practice i guess I’ve never really noticed it not that I’m a professional in any way. I like the husky 346 a lot but not huge fan of the 550 I tried but was only a short while I used it.

 

[Tor R]

I know that’s supposed to be one of the benifits which makes them better balanced and better handling but in practice i guess I’ve never really noticed it not that I’m a professional in any way. I like the husky 346 a lot but not huge fan of the 550 I tried but was only a short while I used it.

Husqvarna's 50 and 60cc are designed to be balanced for tree felling and limbing,
an all-rounder
70cc and above it is less important, inboard or outboard clutch.

 

[afleetcommand]

I want to hear more about the tiny stroke

Same; as that "Swedish" world is a soft wood and limbing world. Remember rev boost? Didn't do a damn thing for hard wood felling. Looks like a softwood focus in specs and also the video.

 

[Ketchup]

Outboards don’t trap bar oil either. Bar oil in the clutch drum contributes to clutch overheat and bearing failure.

 

[cuinrearview]

You guys are heating my bearings up

 

[FergusonTO35]

I'm just glad to see them putting R&D into gas saws instead of trying to force feed us battery power. Husky apparently has plans to keep gas powered machines going for awhile yet, otherwise they wouldn't be doing this. I look forward to seeing Echo's version of an electronic carb or EFI. I suspect they are working on it, probably while taking note of the problems that Stihl and Husky have experienced.

 

[sawmikaze]

Why is that? Worried about heat dissipation? Just curious why you like the outboard better? Definitely not saying one is better than the other just more a matter of opinion i believe. They say the outboard clutch is supposed to be easier on crank bearings but I’m not sure if this is the case or not since the old saws of both types survived well, seems just the newer saws have exhibited bearing issues more and that’s due to stratto saws and 50:1 more than clutch design.

No I just like the way they handle and feel.

I don't care if a saw gets pinched, we have 15 saws laying around to cut it out. And now that I think of it, I never had to unbolt a powerhead from a pinched bar anyway.

 

[sawmikaze]

The biggest advantage of the outboard clutch is that the bar and chain come closer to the center of the chainsaw.

This is why..I know...I sound like Niko. But I actually agreed with him about that.

 

[sawmikaze]

I want to hear more about the tiny stroke

Of course you do, you're homosexual.

 

[Tor R]

The fact that they came up with the 540 xp mk III indicates that Husqvarna has no intention of abandoning petrol-powered chainsaws anytime soon.

But they are probably fully aware that the demands from big cities are for emission-free technology.

We are already seeing it in Europe, when big cities are issuing contracts requiring battery technology. This applies not only to chainsaws, brushcutters and lawnmowers, but also larger ones.

I am glad that Husqvarna designed the 564 xpg, I see it as the most innovative chainsaw from them in the last 20 years.

I have already contacted my dealer and pre-ordered it. It is a winner in my book.

 

[Ketchup]

As usual.


They have.
It seems that, indeed, if they honestly state the displacement, this is the most likely pair of numbers. But here they are still far from 500i. For the 400.0, the cylinder diameter is 50mm, the piston stroke is 34mm, so the ratio is 1.4706, which is also quite a bit more. Unfortunately, I don't yet know what it looks like for the 400.1 (or 363).

I wrote about this (marketing or not) feature, because if the bore is indeed 48 mm, it still in relation to the stroke is not much compared to the 500i or 400.0. Even the 592 XP (or 288 you mentioned) has this ratio greater.
But here the most interesting comparison will be with the 400.1.


This is expected. This is what they also emphasize in the description of the "short stroke engine" (low disturbance forces).
A shorter crank length reduces the inertial force of the piston, with all other parameters unchanged, i.e. piston mass and RPM (still affected by the ratio of crank length to connecting rod length).

That is, for the same displacement, engines that are more oversquare should vibrate less. Of course, this involves some compromises.

EDIT:
Past examples:
272: 52/34 = 1.5294
394: 56/38 = 1.4737
246: 44/30 = 1.4667
And many others having the ratio greater than 1.4.
3120: 60/42 = 1.4286

Great discussion here.
One small thought is many 55-63cc saws run a 34mm stroke. Being 34.5mm would be a bit counter to their marketing and not a remarkable change. The marketing says “short stroke”, but maybe the truth is just “small displacement”.

Better vibration may also be related to rod length. I might be wrong about this, but I feel like rod length/stroke ratio would affect vibration more than bore/stroke. Relatively shorter rods will have more severe angles and create stronger outward forces on the piston. Longer rods should be minutely slower to transfer force as well.